Parents are worried about the safety of vaccinations

Opponents of the measles, mumps and rubella (MMR) vaccine have set up a network of parents to help each other's children catch illnesses.

They believe that by exposing the youngsters to the diseases they will build up their own resistance to the bugs.

At least 500 sets of parents are said to be linked by the informal network - and each is ready to attend "measles parties" where families can meet those infected with the illnesses.

However the government has warned parents against shunning the vaccination scheme.

Mother-of-two Lesley Dove, from Harrow, Middlesex, is refusing to have her children treated with the MMR vaccine.

I think vaccines are bad for the immune system and it is better to let the body develop its own immunity

Mother-of-two Lesley Dove

Instead she lets her children mingle with youngsters who have come down with infections.

However so far Jonathan, eight, and Aurora, five, have failed to contract any of the illnesses.

Ms Dove said: "It is a matter of choice and letting parents make their own decisions.

"I think vaccines are bad for the immune system and it is better to let the body develop its own immunity.

"I would not say that all children should do this because there may be some who have weak immune systems.

"But I will not be letting my own children have the MMR vaccine."

Parents' network

Ms Dove is in contact with about 500 sets of parents and she lets them know if anyone in their area has children who are suffering from measles, mumps or German measles.

The children are then allowed to play with each other at the "parties".

Ms Dove, 36, added: "This is the way it was done until the days of MMR vaccine.

"When I was at school we all just caught these illnesses and got over them and developed our own immunity to them."

We are extremely concerned that any parent might put the health of their child deliberately at risk in this way

Department of Health

Their move is the latest development in the continuing debate over the MMR vaccine.

A spokeswoman for the Department of Health said: "We are extremely concerned that any parent might put the health of their child deliberately at risk in this way.

"The diseases these vaccines protect against are potentially very serious.

"It is every child's right to be protected against these diseases and mmunisation is the safest way for parents to protect their children."

Single vaccines

Other parents are campaigning for the right to give their children separate injections for the three illnesses.

However the British Medical Association recently rejected the idea of making single vaccines available.

They warned that parents who did not have their children vaccinated were threatening the health of other children.

Uptake of the MMR jab has fallen since concerns were first raised in 1998 that it was linked to a rise in autism and bowel disorders.

Immunisation rates have fallen to below recommended World Health Organisation levels, promoting fears that the immunity of the whole population could be threatened.

 

Source: http://news.bbc.co.uk/1/hi/in_depth/health/1448848.stm

Measles is one of the most contagious viral diseases. It is caused by paramyxovirus and is the most unpleasant and the most dangerous of the children's diseases that result in a rash. This is due to the complications of the disease.
It is a notifiable disease in the UK. This means that, by law, cases are required to be reported to a health officer or local government authority.
How is measles transmitted?

• Droplets transfer the infections. Although the sick person may be in isolation, the disease may still spread from room to room.
• Anybody who has not already had measles can be infected.
• Infants up to four months of age will not be infected if their mother has had measles herself because they will be protected by her antibodies.
• The incubation period - the time between infection and the outbreak of the condition - is usually one to two weeks.
• Patients are infectious from four days before the onset of the rash until five days after it appears.

What are the symptoms of measles?
After about 14 days the following symptoms start showing:

• a fever at about 39ºC.
• a cold.
• coughing, possibly with a barking cough.
• sore throat – the lymph nodes in the throat may swell.
• reddish eyes (conjunctivitis).
• sensitivity to light.
• greyish spots, the size of grains of sand may appear in the mucous membrane of the mouth just around the molar teeth. These are called Koplik's spots and can be seen before the rash appears.
• after three to four days the temperature may fall, although it can run high again when the rash appears.
• the rash usually begins around the ears and spreads to the body and the legs within a day or two.
• at first the spots are very small – a couple of millimetres – but they double in size quickly and begin to join together.
• the spots are a clear red colour.
• the temperature, which may run as high as 40ºC, may stay that high for a couple of days. Then it disappears together with the rash, which may leave some brown spots.
• after a week the child will be fit again.

Children who have had measles cannot return to school or childcare before they recover and the temperature is gone.
The doctor should give children under the age of one who are exposed to the disease an immunity injection within five days.
In the UK all children between the age of 12 and 15 months are offered the MMR vaccination, which will protect them from measles, mumps and rubella.
How is measles treated?
The treatment is to stay in bed in a cool room without any bright lights. Medicines for coughing and reducing the temperature should only be given after consulting a GP.
Future prospects
The doctor should be consulted immediately if the condition of the child gets worse or the temperature stays high.
The doctor must make sure there are no further complications such as:

• fitting associated with the high fever (febrile convulsions/febrile fits)
• pneumonia (due to secondary bacterial infection)
• inflammation of the middle ear (otitis media)
• inflammation of the nervous system, eg meningitis, encephalitis. Fortunately, these complications seldom happen and are the exception rather than the rule.

Once a person has had measles, they can never catch it again as the disease gives lifelong immunity.
Measles and pregnancy
If you are planning a pregnancy, you should make sure that you have a measles vaccination unless you have had the disease in the past
Contracting measles during pregnancy has not been reported to cause any subsequent congenital abnormalities in the baby concerned. However, it can result in an infection of the unborn child and may in the worst case result in the death of the baby from the disease.
If in doubt you should consult your GP in order to get the MMR vaccine. This vaccine cannot be given during pregnancy.
The recent large rise in the number of cases of measles in the UK has been directly linked to a fall in the number of children receiving the MMR vaccine.

Based on a text by Dr Per Grinsted

Last updated 24.11.2008

 

Source\; http://www.netdoctor.co.uk/diseases/facts/measles.htm

 

Measles, in spite of available vaccination, remains a heavy public health burden worldwide especially in developing countries with 30-40 million cases occuring annually. In 2002, there were an estimated 610 000 deaths due to measles worldwide, 540 000 of them in children under the age of five, representing 30-40% of the burden of vaccine-preventable diseases in childhood. Measles may be ultimately responsible for more child deaths than any other single agent because of complications from pneumonia, diarrhoea and malnutrition. Measles is also the major cause of preventable blindness in the world, affecting the same disadvantaged populations.

Of the deaths attributable to measles, 98% occur in developing countries, where vitamin A deficiency is common. Case-fatality rates in these countries are usually estimated to be in the range 1-5% but may reach 10-30% in some situations. Specific goals for reduction in measles mortality and morbidity were set by the World Heath Assembly in 1989 and the Word Summit for Children in 1990, as major steps towards the eventual eradication of the disease. Subsequently, target dates of 2000, 2007 and 2010 for its elimination were established for the Region of the Americas, the European Region and the Eastern Mediterranean Region respectively. The aim in the African Region, the South-East Asia Region and Western Pacific Region is to reduce measles mortality.

Several strategies are now developed to increase coverage of immunization including a two-dose schedule, mopping up strategies, supplementary immunization strategies such vitamin A supplementation, one-round national and regional mass immunizations, and development of high-quality case-based measles surveillance supported by regional measles laboratory.

Vaccine

Measles vaccination is one of the most cost effective health interventions available and one of the most powerful tools for providing health equity to poor children. It is cost-effective to improve routine measles vaccination, as preliminary estimates suggest that the cost per life-year gained for expanding measles coverage from 50% to 80% is US$ 2.53 in areas with high disease incidence and high measles case-fatality ratios. Measles vaccine is highly effective, safe and inexpensive. With US$ 0.15 for one measles vaccine dose, children in developing countries can survive exposure to measles without sequelae. However, coverage with measles vaccine is low in many countries due to limited resources. Coverage could be greatly enhanced if the method of administration could be simplified. Current measles vaccination requires injection with a needle and syringe. The drawbacks of the needle and syringe technology are as follows:

• it requires highly skilled personnel to administer the vaccine;
• it is associated with a risk of transmitting blood-borne diseases such as hepatitis and HIV if syringes and needles are re-used. This risk can be minimized if auto-disable syringes are used; and
• injection may be painful and present a risk of infection if a proper technique is not used.

As the natural route of infection for measles virus is the respiratory tract, administration of live attenuated measles vaccine through the respiratory tract has been investigated as an alternative to injection. Early studies have shown fewer acute adverse events following aerosol vaccination, as compared to conventional parenteral vaccine. Aerosolized vaccine is immunogenic and affective in seronegative and seropositive children. More than 4 million children were vaccinated with aerosolized measles vaccine in mass immunization campaigns in Mexico with good public acceptance. Aerosol vaccination can be performed by non-medical staff with some training. As aerosol vaccination uses the same vaccine formulation as parenteral vaccination, most cold chain procedures are identical. Now that the development of a respiratory route of administration is so promising for measles vaccine, WHO has convened a Product Development Group (PDG) to identify critical licensure steps, define clinical trials strategies and assist in protocol design, identify sites for clinical trials and ensure adequate implementation, monitoring and documentation of good practice. Following the current work plan aerosolized measles vaccine could be licensed in 2007 and introduced in practical use in 2009. This project is managed as a partnership between WHO, CDC and the American Red Cross, with funding from the Bill & Melinda Gates Foundation.

In addition, studies are in progress to develop new measles vaccine effective for immunization of infants before 6-months of age. Indeed, infants are refractory to conventional measles vaccines in the presence of maternal anti-measles antibodies. To reach this objective several technologies are currently being tested including DNA vaccines, bacterial vectors, viral vectors (e.g. adenoviruses, poxviruses, alpha viruses) or ISCOMS.

Respiratory syncytial virus (RSV) is a major cause of respiratory illness in young children. RSV causes infection of the lungs and breathing passages. In adults, it may only produce symptoms of a common cold, such as a stuffy or runny nose, sore throat, mild headache, cough, fever, and a general feeling of being ill. But RSV infections can lead to other more serious illnesses in premature babies and kids with diseases that affect the lungs, heart, or immune system.

RSV is highly contagious, and can be spread through droplets containing the virus when a person coughs or sneezes. The virus can also live on surfaces such as countertops or doorknobs, and on hands and clothing. RSV can be easily spread when a person touches an object or surface contaminated with the virus. The infection can spread rapidly through schools and child-care centers. Infants often get it when older kids carry the virus home from school and pass it to them. Almost all kids are infected with RSV at least once by the time they are 2 years old.

RSV infections often occur in epidemics that last from late fall through early spring. Respiratory illness caused by RSV — such as bronchiolitis or pneumonia — usually lasts about a week, but some cases may last several weeks. Doctors typically diagnose RSV by taking a medical history and doing a physical exam. Generally, in healthy kids, it's not necessary to distinguish RSV from a common cold. But in cases where a child has other health conditions, a doctor might want to make a specific diagnosis. RSV is typically identified in nasal secretions, which can be collected either with a cotton swab or by suction through a bulb syringe.

Preventing RSV

Because RSV can be easily spread by touching people or surfaces that are infected, frequent handwashing can go a long way toward preventing the virus from spreading around a household. It's best to wash your hands after having any contact with someone who has any cold symptoms. And keep your school-age child with a cold away from younger siblings — particularly infants — until the symptoms pass.

To prevent serious RSV-related respiratory disease, at-risk kids can be given a monthly injection of a medication consisting of RSV antibodies during peak RSV season (roughly November to April). Because its protection is short-lived, it has to be given in subsequent years until the child is no longer at high risk for severe RSV infection. Ask the doctor if your child is considered high risk.

Treating RSV

Fortunately, most cases of RSV are mild and require no specific treatment from doctors. Antibiotics aren't used because RSV is a virus and antibiotics are only effective against bacteria. Medication may sometimes be given to help open airways.

In an infant, however, an RSV infection can be more serious and may require hospitalization so that the baby can be watched closely, receive fluids, and, if necessary, be treated for breathing problems.

At home, make a child with an RSV infection as comfortable as possible, allow time for recovery, and provide plenty of fluids. The last part can be tricky, however, because babies may not feel like drinking. In that case, offer fluids in small amounts at more frequent intervals than usual.

To help your child breathe easier, use a cool-mist vaporizer during the winter months to keep the air moist — winter air can dry out airways and make the mucus stickier. Avoid hot-water and steam humidifiers, which can be hazardous and can cause scalding. If you use a cool-mist humidifier, clean it daily with household bleach to discourage mold.

If your child is uncomfortable and too young to blow his or her own nose, use a nasal aspirator (or bulb syringe) to remove sticky nasal fluids.

Treat fever using a nonaspirin fever medicine like acetaminophen. Aspirin should NOT be used in children with viral illnesses since its use in such cases has been associated with Reye syndrome, a life-threatening illness.

When to Call the Doctor

Call the doctor if your child has any of these symptoms:

• high fever with ill appearance
• thick nasal discharge that is yellow, green, or gray
• worsening cough or cough that produces yellow, green, or gray mucus

Call also if you think your child might be dehydrated.

In infants, besides the symptoms already mentioned, call the doctor if your baby is unusually irritable or inactive, or refuses to breastfeed or bottle-feed.

Seek immediate medical help if you feel your child is having difficulty breathing or is breathing very rapidly, is lethargic, or if his or her lips or fingernails appear blue.

Reviewed by: Elana Pearl Ben-Joseph, MD
Date reviewed: September 2006

 

Source\; http://kidshealth.org/parent/infections/lung/rsv.html

RSV is the single most important cause of severe LRIs in infants and young children. RSV disease spectrum includes a wide array of respiratory symptoms, from rhinitis and otitis media to pneumonia and bronchiolitis, the latter two diseases being associated with substantial morbidity and mortality. Humans are the only known reservoir for RSV. Spread of the virus from contaminated nasal secretions occurs via large respiratory droplets, so close contact with an infected individual or contaminated surface is required for transmission. RSV can persist for several hours on toys or other objects, which explains the high rate of nosocomial RSV infections, particularly in paediatric wards.

The global annual infection and mortality figures for RSV are estimated to be 64 million and 160 000 respectively. In temperate climates, RSV is well documented as a cause of yearly winter epidemics of acute LRI, including bronchiolitis and pneumonia. In the USA nearly all children, by two years of age, have been infected with RSV, is estimated to be responsible for 18 000 to 75 000 hospitalizations and 90 to 1900 deaths annually. The incidence rate of RSV-associated LRI in otherwise healthy children was calculated as 37 per 1000 child-year in the first two years of life (45 per 1000 child-year in infants less than 6 months old) and the risk of hospitalization as 6 per 1000 child-years (11 per 1000 child-years in the first six months of life). Incidence is higher in children with cardio-pulmonary disease and in those born prematurely, who constitute almost half of RSV-related hospital admissions in the USA. Children who experience a more severe LRI caused by RSV later have an increased incidence of childhood asthma. These studies serve as a basis for anticipating widespread use of RSV vaccines in industrialized countries, where the costs of caring for patients with severe LRI and their sequelae are substantial. RSV also is increasingly recognized as a important cause of morbidity from influenza-like illness in the elderly.

Few population-based estimates of the incidence of RSV disease in developing countries are available, although existing data clearly indicate that, there also, the virus accounts for a high proportion of LRIs in children. Studies in Brazil, Colombia and Thailand show that RSV causes 20–30% of LRI cases in children from 1–4 years of age, a proportion similar to that in industrialized countries. In addition to accurate incidence rates, other important data for developing countries are lacking, such as the severity and case–fatality rates for RSV infection at the community level and the median age of first infection. Preliminary data from community-based studies suggest that the median age of first infection may vary between communities. This information is important for vaccination programme planners, when considering the optimal schedule for vaccination. For example, maternal immunization against RSV would be a desirable strategy to adopt if rates of infection during the first two months of life were found to be high.

Another confusing aspect of the epidemiology of RSV infection that may have an impact on vaccine use is the seasonality of the disease. In Europe and North America, RSV disease occurs as well-defined seasonal outbreaks during the winter and spring months. Studies in developing countries with temperate climates, such as Argentina and Pakistan, have shown a similar seasonal pattern. On the other hand, studies in tropical countries often have reported an increase in RSV in the rainy season but this has not been a constant finding. Indeed, marked differences in the seasonal occurrence of RSV disease have been reported from geographically contiguous regions, e.g. Mozambique and South Africa, or Bangladesh and India. Cultural and behavioral patterns in the community might affect the acquisition and spread of RSV infection. A clear understanding of the local epidemiology of the disease will be critical for the implementation of a successful vaccine development and introduction programme.

Virology

RSV belongs to the family Paramyxoviridae, subfamily Pneumovirinae, genus Pneumovirus. The genome of RSV is a 15,222 nucleotide-long, single-stranded, negative-sense RNA molecule whose tight association with the viral N protein forms a nucleocapsid wrapped inside the viral envelope. The latter contains virally encoded F, G and SH glycoproteins. The F and G glycoproteins are the only two components that induce RSV neutralizing antibody and therefore are of prime importance for vaccine development. The sequence of the F protein, which is responsible for fusion of the virus envelope with the target cell membrane, is highly conserved among RSV isolates. In contrast, that of the G protein, which is responsible for virus attachment, is relatively variable; two groups of RSV strains have been described, the A and B groups, based on differences in the antigenicity of the G glycoprotein. Current efforts are directed towards the development of a vaccine that will incorporate strains in both groups, or will be directed against the F protein.

Vaccine

Development of vaccines to prevent RSV infection have been complicated by the fact that host immune responses appear to play a role in the pathogenesis of the disease. Early studies in the 1960s showed that children vaccinated with a formalin-inactivated RSV vaccine suffered from more severe disease on subsequent exposure to the virus as compared to unvaccinated controls. These early trials resulted in the hospitalization of 80% of vaccinees and two deaths. The enhanced severity of disease has been reproduced in animal models and is thought to result from inadequate levels of serum-neutralizing antibodies, lack of local immunity, and excessive induction of a type 2 helper T-cell-like (Th2) immune response with pulmonary eosinophilia and increased production of IL-4 and IL-5 cytokines.

In addition, naturally acquired immunity to RSV is neither complete nor durable and recurrent infections occur frequently. In a study performed in Houston, Texas, it was found that 83% of the children who acquired RSV infection during their first year of life were reinfected during their second year, and 46% were reinfected during their third year. At least two thirds of these children also were infected with PIV-3 in their first two years of life. Older children and adults, however, usually are protected against RSV-related LRIs, suggesting that protection against severe disease develops after primary infection.

Passive immunization in the form of RSV-neutralizing immune globulin or humanized monoclonal antibodies given prophylactically has been shown to prevent RSV infection in newborns with underlying cardiopulmonary disease, particularly small, premature infants. This demonstrates that humoral antibody plays a major role in protection against disease. In general, secretory IgAs and serum antibodies appear to protect against infection of the upper and lower respiratory tracts, respectively, while T-cell immunity targeted to internal viral proteins appears to terminate viral infections. Although live attenuated vaccines seem preferable for immunization of naive infants than inactivated or subunit vaccines, the latter may be useful for immunization of the elderly and high-risk children, as well as for maternal immunization. Candidate vaccines based on purified F protein (PFP-1, -2 and -3) have been found safe and immunogenic in healthy adults and in children over 12 months of age, with or without underlying pulmonary disease, as well as in elderly subjects and in pregnant women. A Phase I study of PFP-2 was conducted in 35 women in the 30th to 40th week of pregnancy; the vaccine was well tolerated and induced RSV anti-F antibody titres that were persistently fourfold higher in newborns to vaccinated mothers than to those who had received a placebo. No increase in the frequency or morbidity of respiratory disease was observed in infants from vaccinated mothers. Maternal immunization using a PFP subunit vaccine would be an interesting strategy to protect infants younger than six months of age who respond poorly to vaccination.

The efficacy of a subunit PFP-3 vaccine was tested in a Phase III trial on 298 children 1 to 12 years of age with cystic fibrosis. The vaccine was well tolerated and induced a four-fold increase in RSV neutralizing antibody titres, but this was not associated with significant protection against LRI episodes as compared to placebo recipients.

A subunit vaccine consisting of co-purified F, G, and M proteins from RSV A has been tested in healthy adult volunteers in the presence of either alum or polyphosphazene (PCPP) as an adjuvant. Neutralizing antibody responses to RSV A and RSV B were detected in 76–93% of the vaccinees, but titres waned after one year, suggesting that annual immunization with this vaccine will be necessary.

A subunit approach also was investigated using the conserved central domain of the G protein of an RSV-A strain, whose sequence is relatively conserved among groups A and B viruses. A recombinant vaccine candidate, BBG2Na (Pierre Fabre), was developed by fusing this domain (G2Na) to the albumin-binding region (BB) of streptococcal protein G. The candidate vaccine elicited a protective immune response in animals, but was moderately immunogenic in adult human volunteers and its clinical development was interrupted due to the appearance of unexpected side effects (purpura) in a few immunized volunteers. Another RSV candidate vaccine is a synthetic peptide of the conserved region of the G protein administered intranasally, either alone or in combination with cholera toxin. Protection was conferred to mice even without the cholera toxin.

Live, attenuated RSV vaccines that could be delivered to the respiratory mucosa through intranasal immunization have been in development for more than a decade, based on temperature-sensitive (ts), cold-adapted (ca) or cold-passaged (cp) mutant strains of the virus. Difficulties for such a vaccine arise from over- or under-attenuation of the virus and limited genetic stability. Most attenuated live RSV strains tested in humans to date caused mild to moderate congestion in the upper respiratory tract of infants one to two months old and, therefore, were considered as insufficiently attenuated for early infancy. Recombinant RSV vaccines with deletion mutations in nonessential genes (SH, NS1 or NS2), and both cp and ts mutations in essential genes, are currently being evaluated.

Recombinant DNA technology also has provided the possibility of engineering a chimeric virus containing the genes of human PIV-3 surface glycoproteins F and NH, together with those of RSV glycoproteins F and G, in a bovine PIV-3 genetic background. A first candidate vaccine was found to be attenuated and to induce an immune response to both human PIV-3 and RSV in rhesus monkeys and should presently enter clinical trials. Similarly, a bovine PIV-3 genome was engineered to express human PIV-3 F and HN proteins and either native or soluble RSV protein F. Resulting recombinants induced RSV neutralizing antibodies and protective immunity against RSV challenge in African Green monkeys. These b/h PIV3/RSV F vaccines will presently be tested for safety and efficacy in human clinivcal trials as bivalent vaccines to protect infants from both RSV and PIV-3 infection and disease.

Finally, a combination of a live-attenuated vaccine with a subunit vaccine also is being considered for protecting adults against RSV illness, although a preliminary test of this strategy in healthy young and elderly adults was inconclusive.

 

Source: http://www.who.int/vaccine_research/diseases/ari/en/index3.html

 

Infectious pneumonias

• Bacterial pneumonia
• Viral pneumonia
• Fungal pneumonia
• Parasitic pneumonia
• Atypical pneumonia
• Community-acquired pneumonia
• Healthcare-associated pneumonia
• Hospital-acquired pneumonia
• Ventilator-associated pneumonia
• Severe acute respiratory syndrome

Pneumonias caused by infectious or noninfectious agents

• Aspiration pneumonia
• Lipid pneumonia
• Eosinophilic pneumonia
• Bronchiolitis obliterans organizing pneumonia

Noninfectious pneumonia

• Chemical pneumonia

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Pneumonia is an inflammatory illness of the lung.^[1] Frequently, it is described as lung parenchyma/alveolar inflammation and abnormal alveolar filling with fluid (consolidation and exudation).^[2]

The alveoli are microscopic air-filled sacs in the lungs responsible for absorbing oxygen. Pneumonia can result from a variety of causes, including infection with bacteria, viruses, fungi, or parasites, and chemical or physical injury to the lungs. Its cause may also be officially described as idiopathic—that is, unknown—when infectious causes have been excluded.

Typical symptoms associated with pneumonia include cough, chest pain, fever, and difficulty in breathing. Diagnostic tools include x-rays and examination of the sputum. Treatment depends on the cause of pneumonia; bacterial pneumonia is treated with antibiotics.

Pneumonia is a common illness which occurs in all age groups, and is a leading cause of death among the elderly and people who are chronically and terminally ill. Vaccines to prevent certain types of pneumonia are available. The prognosis depends on the type of pneumonia, the appropriate treatment, any complications, and the person's underlying health.

Contents

[hide]

• 1 Signs and symptoms
• 2 Diagnosis
  • 2.1 Investigations
  • 2.2 Combining findings
  • 2.3 Differential diagnosis
• 3 Pathophysiology
  • 3.1 Viruses
  • 3.2 Bacteria
  • 3.3 Fungi
  • 3.4 Parasites
  • 3.5 Idiopathic
• 4 Classification
  • 4.1 Early classification schemes
  • 4.2 Combined clinical classification
    • 4.2.1 Community-acquired pneumonia
    • 4.2.2 Hospital-acquired pneumonia
  • 4.3 Other types of pneumonia
• 5 Treatment
• 6 Complications
  • 6.1 Respiratory and circulatory failure
  • 6.2 Pleural effusion, empyema, and abscess
• 7 Prognosis and mortality
  • 7.1 Clinical prediction rules
• 8 Prevention
• 9 Epidemiology
• 10 History
• 11 See also
• 12 Notes
• 13 External links

[edit] Signs and symptoms

Pneumonia fills the lung's alveoli with fluid, keeping oxygen from reaching the bloodstream. The alveolus on the left is normal, while the alveolus on the right is full of fluid from pneumonia.

People with infectious pneumonia often have a cough producing greenish or yellow sputum, or phlegm and a high fever that may be accompanied by shaking chills. Shortness of breath is also common, as is pleuritic chest pain, a sharp or stabbing pain, either experienced during deep breaths or coughs or worsened by them. People with pneumonia may cough up blood, experience headaches, or develop sweaty and clammy skin. Other possible symptoms are loss of appetite, fatigue, blueness of the skin, nausea, vomiting, mood swings, and joint pains or muscle aches. Less common forms of pneumonia can cause other symptoms; for instance, pneumonia caused by Legionella may cause abdominal pain and diarrhea, while pneumonia caused by tuberculosis or Pneumocystis may cause only weight loss and night sweats. In elderly people manifestations of pneumonia may not be typical. They may develop a new or worsening confusion or may experience unsteadiness, leading to falls. Infants with pneumonia may have many of the symptoms above, but in many cases they are simply sleepy or have a decreased appetite.^[3]

Symptoms of pneumonia need immediate medical evaluation. Physical examination by a health care provider may reveal fever or sometimes low body temperature, an increased respiratory rate, low blood pressure, a high heart rate, or a low oxygen saturation, which is the amount of oxygen in the blood as indicated by either pulse oximetry or blood gas analysis. People who are struggling to breathe, who are confused, or who have cyanosis (blue-tinged skin) require immediate attention.

Physical examination of the lungs may be normal, but often shows decreased expansion of the chest on the affected side, bronchial breathing on auscultation with a stethoscope (harsher sounds from the larger airways transmitted through the inflamed and consolidated lung), and rales (or crackles) heard over the affected area during inspiration. Percussion may be dulled over the affected lung, but increased rather than decreased vocal resonance (which distinguishes it from a pleural effusion).^[3] While these signs are relevant, they are insufficient to diagnose or rule out a pneumonia; moreover, in studies it has been shown that two doctors can arrive at different findings on the same patient.^{[4] [5]}

[edit] Diagnosis

If pneumonia is suspected on the basis of a patient's symptoms and findings from physical examination, further investigations are needed to confirm the diagnosis. Information from a chest X-ray and blood tests are helpful, and sputum cultures in some cases. The chest X-ray is typically used for diagnosis in hospitals and some clinics with X-ray facilities. However, in a community setting (general practice), pneumonia is usually diagnosed based on symptoms and physical examination alone. Diagnosing pneumonia can be difficult in some people, especially those who have other illnesses. Occasionally a chest CT scan or other tests may be needed to distinguish pneumonia from other illnesses.

[edit] Investigations

Pneumonia as seen on chest x-ray. A: Normal chest x-ray. B: Abnormal chest x-ray with shadowing from pneumonia in the right lung (white area, left side of image).

An important test for pneumonia in unclear situations is a chest x-ray. Chest x-rays can reveal areas of opacity (seen as white) which represent consolidation. Pneumonia is not always seen on x-rays, either because the disease is only in its initial stages, or because it involves a part of the lung not easily seen by x-ray. In some cases, chest CT (computed tomography) can reveal pneumonia that is not seen on chest x-ray. X-rays can be misleading, because other problems, like lung scarring and congestive heart failure, can mimic pneumonia on x-ray.^[6] Chest x-rays are also used to evaluate for complications of pneumonia (see below.)

If antibiotics fail to improve the patient's health, or if the health care provider has concerns about the diagnosis, a culture of the person's sputum may be requested. Sputum cultures generally take at least two to three days, so they are mainly used to confirm that the infection is sensitive to an antibiotic that has already been started. A blood sample may similarly be cultured to look for bacteria in the blood. Any bacteria identified are then tested to see which antibiotics will be most effective.

A complete blood count may show a high white blood cell count, indicating the presence of an infection or inflammation. In some people with immune system problems, the white blood cell count may appear deceptively normal. Blood tests may be used to evaluate kidney function (important when prescribing certain antibiotics) or to look for low blood sodium. Low blood sodium in pneumonia is thought to be due to extra anti-diuretic hormone produced when the lungs are diseased (SIADH). Specific blood serology tests for other bacteria (Mycoplasma, Legionella and Chlamydophila) and a urine test for Legionella antigen are available. Respiratory secretions can also be tested for the presence of viruses such as influenza, respiratory syncytial virus, and adenovirus. Liver function tests should be carried out to test for damage caused by sepsis.^[3]

[edit] Combining findings

One study created a prediction rule that found the five following signs best predicted infiltrates on the chest radiograph of 1134 patients presenting to an emergency room:^[7]

• Temperature > 100 degrees F (37.8 degrees C)
• Pulse > 100 beats/min
• Rales/crackles
• Decreased breath sounds
• Absence of asthma

The probability of an infiltrate in two separate validations was based on the number of findings:

• 5 findings - 84% to 91% probability
• 4 findings - 58% to 85%
• 3 findings - 35% to 51%
• 2 findings - 14% to 24%
• 1 findings - 5% to 9%
• 0 findings - 2% to 3%

A subsequent study^[8] comparing four prediction rules to physician judgment found that two rules, the one above^[7] and also^[9] were more accurate than physician judgment because of the increased specificity of the prediction rules.

[edit] Differential diagnosis

Several diseases and/or conditions can present with similar clinical features to pneumonia and as such care must be taken in the proper diagnosis of the disease. Chronic obstructive pulmonary disease (COPD) or asthma can present with a polyphonic wheeze, similar to that of pneumonia. Pulmonary edema can be mistaken for pneumonia due to its ability to show a third heart sound and present with an abnormal ECG. Other diseases to be taken into consideration include bronchiectasis, lung cancer and pulmonary emboli.^[3]

[edit] Pathophysiology

Upper panel shows a normal lung under a microscope. The white spaces are alveoli that contain air. Lower panel shows a lung with pneumonia under a microscope. The alveoli are filled with inflammation and debris.

Pneumonia can be caused by microorganisms, irritants and unknown causes. When pneumonias are grouped this way, infectious causes are the most common type.

The symptoms of infectious pneumonia are caused by the invasion of the lungs by microorganisms and by the immune system's response to the infection. Although more than one hundred strains of microorganism can cause pneumonia, only a few are responsible for most cases. The most common causes of pneumonia are viruses and bacteria. Less common causes of infectious pneumonia are fungi and parasites.

[edit] Viruses

Main article: Viral pneumonia

Viruses invade cells in order to reproduce. Typically, a virus reaches the lungs when airborne droplets are inhaled through the mouth and nose. Once in the lungs, the virus invades the cells lining the airways and alveoli. This invasion often leads to cell death, either when the virus directly kills the cells, or through a type of cell controlled self-destruction called apoptosis. When the immune system responds to the viral infection, even more lung damage occurs. White blood cells, mainly lymphocytes, activate certain chemical cytokines which allow fluid to leak into the alveoli. This combination of cell destruction and fluid-filled alveoli interrupts the normal transportation of oxygen into the bloodstream.

As well as damaging the lungs, many viruses affect other organs and thus disrupt many body functions. Viruses can also make the body more susceptible to bacterial infections; for which reason bacterial pneumonia often complicates viral pneumonia.

Viral pneumonia is commonly caused by viruses such as influenza virus, respiratory syncytial virus (RSV), adenovirus, and metapneumovirus. Herpes simplex virus is a rare cause of pneumonia except in newborns. People with weakened immune systems are also at risk of pneumonia caused by cytomegalovirus (CMV).

[edit] Bacteria

Main article: Bacterial pneumonia

Bacteria typically enter the lung when airborne droplets are inhaled, but can also reach the lung through the bloodstream when there is an infection in another part of the body. Many bacteria live in parts of the upper respiratory tract, such as the nose, mouth and sinuses, and can easily be inhaled into the alveoli. Once inside, bacteria may invade the spaces between cells and between alveoli through connecting pores. This invasion triggers the immune system to send neutrophils, a type of defensive white blood cell, to the lungs. The neutrophils engulf and kill the offending organisms, and also release cytokines, causing a general activation of the immune system. This leads to the fever, chills, and fatigue common in bacterial and fungal pneumonia. The neutrophils, bacteria, and fluid from surrounding blood vessels fill the alveoli and interrupt normal oxygen transportation.

The bacterium Streptococcus pneumoniae, a common cause of pneumonia, photographed through an electron microscope.

Bacteria often travel from an infected lung into the bloodstream, causing serious or even fatal illness such as septic shock, with low blood pressure and damage to multiple parts of the body including the brain, kidneys, and heart. Bacteria can also travel to the area between the lungs and the chest wall (the pleural cavity) causing a complication called an empyema.

The most common causes of bacterial pneumonia are Streptococcus pneumoniae, Gram-positive bacteria and "atypical" bacteria. The terms "Gram-positive" and "Gram-negative" refer to the bacteria's color (purple or red, respectively) when stained using a process called the Gram stain. The term "atypical" is used because atypical bacteria commonly affect healthier people, cause generally less severe pneumonia, and respond to different antibiotics than other bacteria.

The types of Gram-positive bacteria that cause pneumonia can be found in the nose or mouth of many healthy people. Streptococcus pneumoniae, often called "pneumococcus", is the most common bacterial cause of pneumonia in all age groups except newborn infants. Another important Gram-positive cause of pneumonia is Staphylococcus aureus, with Streptococcus agalactiae being an important cause of pneumonia in newborn babies. Gram-negative bacteria cause pneumonia less frequently than gram-positive bacteria. Some of the gram-negative bacteria that cause pneumonia include Haemophilus influenzae, Klebsiella pneumoniae, Escherichia coli, Pseudomonas aeruginosa and Moraxella catarrhalis. These bacteria often live in the stomach or intestines and may enter the lungs if vomit is inhaled. "Atypical" bacteria which cause pneumonia include Chlamydophila pneumoniae, Mycoplasma pneumoniae, and Legionella pneumophila.

[edit] Fungi

Main article: Fungal pneumonia

Fungal pneumonia is uncommon, but it may occur in individuals with immune system problems due to AIDS, immunosuppresive drugs, or other medical problems. The pathophysiology of pneumonia caused by fungi is similar to that of bacterial pneumonia. Fungal pneumonia is most often caused by Histoplasma capsulatum, blastomyces, Cryptococcus neoformans, Pneumocystis jiroveci, and Coccidioides immitis. Histoplasmosis is most common in the Mississippi River basin, and coccidioidomycosis in the southwestern United States.

[edit] Parasites

Main article: Parasitic pneumonia

A variety of parasites can affect the lungs. These parasites typically enter the body through the skin or by being swallowed. Once inside, they travel to the lungs, usually through the blood. There, as in other cases of pneumonia, a combination of cellular destruction and immune response causes disruption of oxygen transportation. One type of white blood cell, the eosinophil, responds vigorously to parasite infection. Eosinophils in the lungs can lead to eosinophilic pneumonia, thus complicating the underlying parasitic pneumonia. The most common parasites causing pneumonia are Toxoplasma gondii, Strongyloides stercoralis, and Ascariasis.

[edit] Idiopathic

Main article: Idiopathic interstitial pneumonia

Idiopathic interstitial pneumonias (IIP) are a class as diffuse lung diseases. In some types of IIP, e.g. some types of usual interstitial pneumonia, the cause, indeed, is unknown or idiopathic. In some types of IIP the cause of the pneumonia is known, e.g. desquamative interstitial pneumonia is caused by smoking, and the name is a misnomer.

[edit] Classification

Pneumonias can be classified in several ways. Pathologists originally classified them according to the anatomic changes that were found in the lungs during autopsies. As more became known about the microorganisms causing pneumonia, a microbiologic classification arose, and with the advent of x-rays, a radiological classification. Another important system of classification is the combined clinical classification, which combines factors such as age, risk factors for certain microorganisms, the presence of underlying lung disease and underlying systemic disease, and whether the person has recently been hospitalized.

[edit] Early classification schemes

Initial descriptions of pneumonia focused on the anatomic or pathologic appearance of the lung, either by direct inspection at autopsy or by its appearance under a microscope.

• A lobar pneumonia is an infection that only involves a single lobe, or section, of a lung. Lobar pneumonia is often due to Streptococcus pneumoniae (though Klebsiella pneumoniae is also possible.)^[10]
• Multilobar pneumonia involves more than one lobe, and it often causes a more severe illness.
• Interstitial pneumonia involves the areas in between the alveoli, and it may be called "interstitial pneumonitis." It is more likely to be caused by viruses or by atypical bacteria.

The discovery of x-rays made it possible to determine the anatomic type of pneumonia without direct examination of the lungs at autopsy and led to the development of a radiological classification. Early investigators distinguished between typical lobar pneumonia and atypical (e.g. Chlamydophila) or viral pneumonia using the location, distribution, and appearance of the opacities they saw on chest x-rays. Certain x-ray findings can be used to help predict the course of illness, although it is not possible to clearly determine the microbiologic cause of a pneumonia with x-rays alone.

With the advent of modern microbiology, classification based upon the causative microorganism became possible. Determining which microorganism is causing an individual's pneumonia is an important step in deciding treatment type and length. Sputum cultures, blood cultures, tests on respiratory secretions, and specific blood tests are used to determine the microbiologic classification. Because such laboratory testing typically takes several days, microbiologic classification is usually not possible at the time of initial diagnosis.

[edit] Combined clinical classification

Traditionally, clinicians have classified pneumonia by clinical characteristics, dividing them into "acute" (less than three weeks duration) and "chronic" pneumonias. This is useful because chronic pneumonias tend to be either non-infectious, or mycobacterial, fungal, or mixed bacterial infections caused by airway obstruction. Acute pneumonias are further divided into the classic bacterial bronchopneumonias (such as Streptococcus pneumoniae), the atypical pneumonias (such as the interstitial pneumonitis of Mycoplasma pneumoniae or Chlamydia pneumoniae), and the aspiration pneumonia syndromes.

Chronic pneumonias, on the other hand, mainly include those of Nocardia, Actinomyces and Blastomyces dermatitidis, as well as the granulomatous pneumonias (Mycobacterium tuberculosis and atypical mycobacteria, Histoplasma capsulatum and Coccidioides immitis).^[11]

The combined clinical classification, now the most commonly used classification scheme, attempts to identify a person's risk factors when he or she first comes to medical attention. The advantage of this classification scheme over previous systems is that it can help guide the selection of appropriate initial treatments even before the microbiologic cause of the pneumonia is known. There are two broad categories of pneumonia in this scheme: community-acquired pneumonia and hospital-acquired pneumonia. A recently introduced type of healthcare-associated pneumonia (in patients living outside the hospital who have recently been in close contact with the health care system) lies between these two categories.

[edit] Community-acquired pneumonia

Main article: Community-acquired pneumonia

Community-acquired pneumonia (CAP) is infectious pneumonia in a person who has not recently been hospitalized. CAP is the most common type of pneumonia. The most common causes of CAP vary depending on a person's age, but they include Streptococcus pneumoniae, viruses, the atypical bacteria, and Haemophilus influenzae. Overall, Streptococcus pneumoniae is the most common cause of community-acquired pneumonia worldwide. Gram-negative bacteria cause CAP in certain at-risk populations. CAP is the fourth most common cause of death in the United Kingdom and the sixth in the United States. An outdated term, "walking pneumonia", has been used to describe a type of community-acquired pneumonia of less severity (hence the fact that the patient can continue to "walk" rather than require hospitalization). Walking pneumonia is usually caused by a virus or by atypical bacteria.

[edit] Hospital-acquired pneumonia

Main article: Hospital-acquired pneumonia

Hospital-acquired pneumonia, also called nosocomial pneumonia, is pneumonia acquired during or after hospitalization for another illness or procedure with onset at least 72 hrs after admission. The causes, microbiology, treatment and prognosis are different from those of community-acquired pneumonia. Up to 5% of patients admitted to a hospital for other causes subsequently develop pneumonia. Hospitalized patients may have many risk factors for pneumonia, including mechanical ventilation, prolonged malnutrition, underlying heart and lung diseases, decreased amounts of stomach acid, and immune disturbances. Additionally, the microorganisms a person is exposed to in a hospital are often different from those at home . Hospital-acquired microorganisms may include resistant bacteria such as MRSA, Pseudomonas, Enterobacter, and Serratia. Because individuals with hospital-acquired pneumonia usually have underlying illnesses and are exposed to more dangerous bacteria, it tends to be more deadly than community-acquired pneumonia. Ventilator-associated pneumonia (VAP) is a subset of hospital-acquired pneumonia. VAP is pneumonia which occurs after at least 48 hours of intubation and mechanical ventilation.

[edit] Other types of pneumonia

• Severe acute respiratory syndrome (SARS)

SARS is a highly contagious and deadly type of pneumonia which first occurred in 2002 after initial outbreaks in China. SARS is caused by the SARS coronavirus, a previously unknown pathogen.

• Bronchiolitis obliterans organizing pneumonia (BOOP)

BOOP is caused by inflammation of the small airways of the lungs. It is also known as cryptogenic organizing pneumonitis (COP).

• Eosinophilic pneumonia

Eosinophilic pneumonia is invasion of the lung by eosinophils, a particular kind of white blood cell. Eosinophilic pneumonia often occurs in response to infection with a parasite or after exposure to certain types of environmental factors.

• Chemical pneumonia

Chemical pneumonia (usually called chemical pneumonitis) is caused by chemical toxicants such as pesticides, which may enter the body by inhalation or by skin contact. When the toxic substance is an oil, the pneumonia may be called lipoid pneumonia.

• Aspiration pneumonia

Aspiration pneumonia (or aspiration pneumonitis) is caused by aspirating foreign objects which are usually oral or gastric contents, either while eating, or after reflux or vomiting which results in bronchopneumonia. The resulting lung inflammation is not an infection but can contribute to one, since the material aspirated may contain anaerobic bacteria or other unusual causes of pneumonia. Aspiration is a leading cause of death among hospital and nursing home patients, since they often cannot adequately protect their airways and may have otherwise impaired defenses.

• Dust pneumonia

Dust pneumonia describes disorders caused by excessive exposure to dust storms, particularly during the Dust Bowl in the United States. With dust pneumonia, dust settles all the way into the alveoli of the lungs, stopping the cilia from moving and preventing the lungs from ever clearing themselves.

• Necrotizing pneumonia, although overlapping with many other classifications, includes pneumonias that cause substantial necrosis of lung cells, and sometimes even lung abscess. Implicated bacteria are extremely commonly anaerobic bacteria, with or without additional facultatively anaerobic ones like Staphylococcus aureus, Klebsiella pneumoniae and Streptococcus pyogenes.^[11] Type 3 pneumococcus is uncommonly implicated.^[11]
• Opportunistic pneumonia includes those that frequently strike immunocompromised victims. Main pathogens are cytomegalovirus, Pneumocystis jiroveci, Mycobacterium avium-intracellulare, invasive aspergillosis, invasive candidiasis, as well as the "usual bacteria" that strike immunocompetent people as well.^[11]

[edit] Treatment

Most cases of pneumonia can be treated without hospitalization. Typically, oral antibiotics, rest, fluids, and home care are sufficient for complete resolution. However, people with pneumonia who are having trouble breathing, people with other medical problems, and the elderly may need more advanced treatment. If the symptoms get worse, the pneumonia does not improve with home treatment, or complications occur, the person will often have to be hospitalized.

Antibiotics are used to treat bacterial pneumonia. In contrast, antibiotics are not useful for viral pneumonia, although they sometimes are used to treat or prevent bacterial infections that can occur in lungs damaged by a viral pneumonia. The antibiotic choice depends on the nature of the pneumonia, the most common microorganisms causing pneumonia in the local geographic area, and the immune status and underlying health of the individual. Treatment for pneumonia should ideally be based on the causative microorganism and its known antibiotic sensitivity. However, a specific cause for pneumonia is identified in only 50% of people, even after extensive evaluation. Because treatment should generally not be delayed in any person with a serious pneumonia, empiric treatment is usually started well before laboratory reports are available. In the United Kingdom, amoxicillin and clarithromycin or erythromycin are the antibiotics selected for most patients with community-acquired pneumonia; patients allergic to penicillins are given erythromycin instead of amoxicillin. In North America, where the "atypical" forms of community-acquired pneumonia are becoming more common, azithromycin, clarithromycin, and the fluoroquinolones have displaced amoxicillin as first-line treatment. The duration of treatment has traditionally been seven to ten days, but there is increasing evidence that shorter courses (as short as three days) are sufficient.^[12][13][14]

Antibiotics for hospital-acquired pneumonia include vancomycin, third- and fourth-generation cephalosporins, carbapenems, fluoroquinolones, and aminoglycosides. These antibiotics are usually given intravenously. Multiple antibiotics may be administered in combination in an attempt to treat all of the possible causative microorganisms. Antibiotic choices vary from hospital to hospital because of regional differences in the most likely microorganisms, and because of differences in the microorganisms' abilities to resist various antibiotic treatments.

People who have difficulty breathing due to pneumonia may require extra oxygen. Extremely sick individuals may require intensive care treatment, often including intubation and artificial ventilation.

Viral pneumonia caused by influenza A may be treated with rimantadine or amantadine, while viral pneumonia caused by influenza A or B may be treated with oseltamivir or zanamivir. These treatments are beneficial only if they are started within 48 hours of the onset of symptoms. Many strains of H5N1 influenza A, also known as avian influenza or "bird flu," have shown resistance to rimantadine and amantadine. There are no known effective treatments for viral pneumonias caused by the SARS coronavirus, adenovirus, hantavirus, or parainfluenza virus.

[edit] Complications

Sometimes pneumonia can lead to additional complications. Complications are more frequently associated with bacterial pneumonia than with viral pneumonia. The most important complications include:

[edit] Respiratory and circulatory failure

Because pneumonia affects the lungs, often people with pneumonia have difficulty breathing, and it may not be possible for them to breathe well enough to stay alive without support. Non-invasive breathing assistance may be helpful, such as with a bi-level positive airway pressure machine. In other cases, placement of an endotracheal tube (breathing tube) may be necessary, and a ventilator may be used to help the person breathe.

Pneumonia can also cause respiratory failure by triggering acute respiratory distress syndrome (ARDS), which results from a combination of infection and inflammatory response. The lungs quickly fill with fluid and become very stiff. This stiffness, combined with severe difficulties extracting oxygen due to the alveolar fluid, create a need for mechanical ventilation.

Pleural effusion. Chest x-ray showing a pleural effusion. The A arrow indicates "fluid layering" in the right chest. The B arrow indicates the width of the right lung. The volume of useful lung is reduced because of the collection of fluid around the lung.

Sepsis and septic shock are potential complications of pneumonia. Sepsis occurs when microorganisms enter the bloodstream and the immune system responds by secreting cytokines. Sepsis most often occurs with bacterial pneumonia; Streptococcus pneumoniae is the most common cause. Individuals with sepsis or septic shock need hospitalization in an intensive care unit. They often require intravenous fluids and medications to help keep their blood pressure from dropping too low. Sepsis can cause liver, kidney, and heart damage, among other problems, and it often causes death.

[edit] Pleural effusion, empyema, and abscess

Occasionally, microorganisms infecting the lung will cause fluid (a pleural effusion) to build up in the space that surrounds the lung (the pleural cavity). If the microorganisms themselves are present in the pleural cavity, the fluid collection is called an empyema. When pleural fluid is present in a person with pneumonia, the fluid can often be collected with a needle (thoracentesis) and examined. Depending on the results of this examination, complete drainage of the fluid may be necessary, often requiring a chest tube. In severe cases of empyema, surgery may be needed. If the fluid is not drained, the infection may persist, because antibiotics do not penetrate well into the pleural cavity.

Rarely, bacteria in the lung will form a pocket of infected fluid called an abscess. Lung abscesses can usually be seen with a chest x-ray or chest CT scan. Abscesses typically occur in aspiration pneumonia and often contain several types of bacteria. Antibiotics are usually adequate to treat a lung abscess, but sometimes the abscess must be drained by a surgeon or radiologist.

[edit] Prognosis and mortality

With treatment, most types of bacterial pneumonia can be cleared within two to four weeks.^[15] Viral pneumonia may last longer, and mycoplasmal pneumonia may take four to six weeks to resolve completely.^[15] The eventual outcome of an episode of pneumonia depends on how ill the person is when he or she is first diagnosed.^[15]

In the United States, about one of every twenty people with pneumococcal pneumonia die.^[16] In cases where the pneumonia progresses to blood poisoning (bacteremia), just over 20% of sufferers die.^[17]

The death rate (or mortality) also depends on the underlying cause of the pneumonia. Pneumonia caused by Mycoplasma, for instance, is associated with little mortality. However, about half of the people who develop methicillin-resistant Staphylococcus aureus (MRSA) pneumonia while on a ventilator will die.^[18] In regions of the world without advanced health care systems, pneumonia is even deadlier. Limited access to clinics and hospitals, limited access to x-rays, limited antibiotic choices, and inability to treat underlying conditions inevitably leads to higher rates of death from pneumonia.

[edit] Clinical prediction rules

Clinical prediction rules have been developed to more objectively prognosticate outcomes in pneumonia. These rules can be helpful in deciding whether or not to hospitalize the person.

• Pneumonia severity index (or PORT Score)^[19] - online calculator
• CURB-65 score, which takes into account the severity of symptoms, any underlying diseases, and age^[20] - online calculator

[edit] Prevention

There are several ways to prevent infectious pneumonia. Appropriately treating underlying illnesses (such as AIDS) can decrease a person's risk of pneumonia. Smoking cessation is important not only because it helps to limit lung damage, but also because cigarette smoke interferes with many of the body's natural defenses against pneumonia.

Research shows that there are several ways to prevent pneumonia in newborn infants. Testing pregnant women for Group B Streptococcus and Chlamydia trachomatis, and then giving antibiotic treatment if needed, reduces pneumonia in infants. Suctioning the mouth and throat of infants with meconium-stained amniotic fluid decreases the rate of aspiration pneumonia.

Vaccination is important for preventing pneumonia in both children and adults. Vaccinations against Haemophilus influenzae and Streptococcus pneumoniae in the first year of life have greatly reduced their role in pneumonia in children. Vaccinating children against Streptococcus pneumoniae has also led to a decreased incidence of these infections in adults because many adults acquire infections from children. A vaccine against Streptococcus pneumoniae is also available for adults. In the U.S., it is currently recommended for all healthy individuals older than 65 and any adults with emphysema, congestive heart failure, diabetes mellitus, cirrhosis of the liver, alcoholism, cerebrospinal fluid leaks, or those who do not have a spleen. A repeat vaccination may also be required after five or ten years.^[21]

Influenza vaccines should be given yearly to the same individuals who receive vaccination against Streptococcus pneumoniae. In addition, health care workers, nursing home residents, and pregnant women should receive the vaccine.^[22] When an influenza outbreak is occurring, medications such as amantadine, rimantadine, zanamivir, and oseltamivir can help prevent influenza.^[23][24]

[edit] Epidemiology

Pneumonia is a common illness in all parts of the world. It is a major cause of death among all age groups. In children, the majority of deaths occur in the newborn period, with over two million deaths a year worldwide. The World Health Organization estimates that one in three newborn infant deaths are due to pneumonia^[25] and WHO also estimates that up to 1 million of these (vaccine preventable) deaths are caused by the bacteria Streptococcus pneumoniae, and 90% of these deaths take place in developing countries.^[26] Mortality from pneumonia generally decreases with age until late adulthood. Elderly individuals, however, are at particular risk for pneumonia and associated mortality.

In the United Kingdom, the annual incidence of pneumonia is approximately 6 cases for every 1000 people for the 18–39 age group. For those over 75 years of age, this rises to 75 cases for every 1000 people. Roughly 20–40% of individuals who contract pneumonia require hospital admission of which between 5–10% are admitted to a critical care unit. Similarly, the mortality rate in the UK is around 5–10%.^[3]

More cases of pneumonia occur during the winter months than during other times of the year. Pneumonia occurs more commonly in males than females, and more often in Blacks than Caucasians due to differences in synthesizing Vitamin D from sunlight. Individuals with underlying illnesses such as Alzheimer's disease, cystic fibrosis, emphysema, tobacco smoking, alcoholism, or immune system problems are at increased risk for pneumonia.^[27] These individuals are also more likely to have repeated episodes of pneumonia. People who are hospitalized for any reason are also at high risk for pneumonia.

[edit] History

Hippocrates, the ancient Greek physician known as the "father of medicine."

The symptoms of pneumonia were described by Hippocrates (c. 460 BC – 370 BC):

Peripneumonia, and pleuritic affections, are to be thus observed: If the fever be acute, and if there be pains on either side, or in both, and if expiration be if cough be present, and the sputa expectorated be of a blond or livid color, or likewise thin, frothy, and florid, or having any other character different from the common... When pneumonia is at its height, the case is beyond remedy if he is not purged, and it is bad if he has dyspnoea, and urine that is thin and acrid, and if sweats come out about the neck and head, for such sweats are bad, as proceeding from the suffocation, rales, and the violence of the disease which is obtaining the upper hand.^[28]

However, Hippocrates referred to pneumonia as a disease "named by the ancients." He also reported the results of surgical drainage of empyemas. Maimonides (1138–1204 AD) observed "The basic symptoms which occur in pneumonia and which are never lacking are as follows: acute fever, sticking [pleuritic] pain in the side, short rapid breaths, serrated pulse and cough."^[29] This clinical description is quite similar to those found in modern textbooks, and it reflected the extent of medical knowledge through the Middle Ages into the 19th century.

Bacteria were first seen in the airways of individuals who died from pneumonia by Edwin Klebs in 1875.^[30] Initial work identifying the two common bacterial causes Streptococcus pneumoniae and Klebsiella pneumoniae was performed by Carl Friedländer^[31] and Albert Fränkel^[32] in 1882 and 1884, respectively. Friedländer's initial work introduced the Gram stain, a fundamental laboratory test still used to identify and categorize bacteria. Christian Gram's paper describing the procedure in 1884 helped differentiate the two different bacteria and showed that pneumonia could be caused by more than one microorganism.^[33]

Sir William Osler, known as "the father of modern medicine," appreciated the morbidity and mortality of pneumonia, describing it as the "captain of the men of death" in 1918. However, several key developments in the 1900s improved the outcome for those with pneumonia. With the advent of penicillin and other antibiotics, modern surgical techniques, and intensive care in the twentieth century, mortality from pneumonia dropped precipitously in the developed world. Vaccination of infants against Haemophilus influenzae type b began in 1988 and led to a dramatic decline in cases shortly thereafter.^[34] Vaccination against Streptococcus pneumoniae in adults began in 1977 and in children began in 2000, resulting in a similar decline.^[35]

Sir Osler applied the phrase "Captain of the Men of Death" to pneumonia, as it had overtaken tuberculosis as one of the leading causes of death in his time. The phrase was originally coined by John Bunyan with regard to consumption, or tuberculosis. ^[36]

^{Source: http://en.wikipedia.org/wiki/Pneumonia}