Pneumonia

PneumonisWedge09[1]

Pneumonia is an acute or chronic inflammation of the parenchyma of the lung. Most cases are due to infection by bacteria or viruses, a few to inhalation of chemicals, fungi, parasites or trauma. Pneumonia is most commonly classified by the area of lung affected: lobar pneumonia, bronchial pneumonia and interstitial pneumonia. The signs and symptoms of pneumonia vary from mild to severe. The most common symptoms of pneumonia include productive cough, fever, dyspnea and chest pain.


Presentation

Individuals with infectious pneumonia generally have a productive cough, sharp pain in between breaths, fever accompanied with shaking chills and an increased respiratory rate. For the elderly, confusion is often the most prominent sign [6]. In children under 5, the typical signs and symptoms are fever, fast or difficult breathing and cough.

Fever is not a specific symptom because it occurs in many other illnesses and may be absent in with more severe conditions or malnutrition. Again, children less than two months old do not present with cough. In severe cases, other symptoms to expect include a blue-tinged skin, decreased thirst, convulsions, constant vomiting, decreased levels of consciousness and temperature always at the extremes.

Both bacterial and viral cases of pneumonia have similar symptoms.

Some causative agents are linked with classic but often non-specific characteristics. For instance pneumonia caused by Klebsiella may have the “currant jelly” symptom or bloody sputum, pneumonia caused by Streptococcus pneumonia is linked with rusty and coloured sputum while Legionella-cuased pneumonia is associated with abdominal pain, diarrhea or confusion.

Workup

Physical examinations and imaging studies are the chief methods of diagnosis [7].

Diagnosis for pneumonia is often based on a combination of physical signs and a chest X-ray. The underlying cause however can be difficult to confirm as there is often no definitive test for distinguishing between pneumonia of bacterial origin and pneumonia of other origins. In children, the WHO guideline defines pneumonia clinically as decreased level of consciousness, chest indrawing, rapid respiratory rate, difficulty in breathing and/or cough.

Treatment

Pneumonia is often treated with antibiotics. Most of the cases require the intake of oral antibiotics and these are often prescribed at any health care centre [8]. The average case of pneumonia can be treated with inexpensive oral antibiotics at the community level by trained community health workers. Hospitalisation is only recommended for severe cases of pneumonia and for cases of pneumonia in infants younger than 2 months of age.

Prognosis

The prognosis is generally positive as most kinds of bacterial pneumonia stabilises with a week. Most symptoms get resolved within a week. Findings in X-ray clear within four weeks and mortality is generally low [5]. People with other lung conditions and the elderly may recover after a longer period of time (as long as 3 months).

Etiology

Pneumonia arises due to infections caused primarily by bacteria or viruses. In less common cases, fungi and parasites can bring about pneumonia. Even though over 100 types of infectious agents have been recorded, only a few of these cause the majority of pneumonia cases [2]. In 45% of infections in children, both viruses and bacteria may be responsible for the condition. In adult pneumonia infections, the figure is placed at 15%. Despite careful testing, it is possible to not isolate any causative agent in 50% of pneumonia cases.

Epidemiology

Pneumonia is a very common condition that affects around 450 million people around the world. It is equally a major cause of death amongst people of all age groups as it results in over 4 million deaths. This accounts for more than 7% of the total deaths recorded around the world each year. The rates are at their peak in children who are less than five years old and in adults who are older than the age of 75. Every year, more than 1.1 million children with the condition die every year [3]. The occurrence is 5 times lower in the developed world when compared to the developing world. In the United States for example, pneumonia is the 8th leading cause of deaths.

Sex distribution
Age distribution

Pathophysiology

Viral cases

The Viruses can enter the lung via different routes. For instance, respiratory syncytial virus is often contacted when individuals touch contaminated objects before touching their eyes or nose while other forms of viral infections occur when contaminated airborne droplets get inhaled through the mouth or nose. As soon as they get into the upper airway, the viruses will move to the lungs where the cells lining the airways, lung parenchyma and the alveoli get invaded [4].

Bacterial cases

The bacteria get into the lungs through small aspirations of organisms that reside in the throat or nose. Most normal people have these aspirations while asleep. Although the throat contains bacteria always, the potentially infectious ones are found there only at certain periods and under specific conditions. Contaminated airborne droplets are responsible for the deposition of Mycobacterium tuberculosis and Legionella pneumophilia. The bacteria can also spread via the blood. As soon as the bacteria is in the lungs, the spaces between cells and alveoli are invaded and the neutrophils and macrophages attempt to get rid of the bacteria. The resultant combination brings about the image seen in X-ray.

Prevention

The prevention of pneumonia is one of the most important strategies to reduce the incidence of child mortality. The most effective way to prevent pneumonia is immunization against measles,pertussis, Pneumococcus and Haemophilus influenzae type B.

Adequate nutrition is also important in improving the natural defences of a child beginning with exclusive breastfeeding for the first six months of life. In addition to being effective in the prevention of pneumonia, the length of periods of illness in a child is reduced greatly [9].

The number of people who fall ill with pneumonia can also be prevented by encouraging good hygiene in crowded homes and addressing of environmental factors such as indoor pollution.

For children who are infected with HIV, daily intake of cotrimoxazole is required so as to decrease the risk of contracting pneumonia.

Summary

Pneumonia is an acute respiratory infection of the lungs [1]. The lungs are filled with small sacs called alveoli. These fill when a healthy individual breathes in. In an individual with any form of pneumonia, the sac get s filled with pus and fluid and this makes breathing painful, thereby limiting the individual’s ability to take in oxygen.

Patient Information

Pneumonia is a condition that affects the air sacs in either one lung or both. Cough producing phlegm or pus, difficulty in breathing, chills and fever are common symptoms of this condition and this happens when the affected air sac gets filled with fluid or pus. 

There are different types of organisms that can cause pneumonia. This includes bacteria, viruses and fungi. 

The level of seriousness of this condition varies greatly but it is the most serious amongst infants, young children and people older than 65 years of age. People with underlying health conditions or weakened immune systems also get more serious cases of pneumonia. 

The chances of recovery from pneumonia is high though as there are several antiviral medications for treating it. 

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References

  1. Guidelines for the management of community acquired pneumonia in adults; British Thoracic Society (2009), Thorax Vol 64 Sup III
  2. Durrington HJ, Summers C; Recent changes in the management of community acquired pneumonia in adults. BMJ. 2008 Jun 21;336(7658):1429-33.
  3. Guidelines for the management of adult lower respiratory tract infections, European Respiratory Society and European Society of Clinical Microbiology and Infectious Diseases (September 2011)
  4. Chest infections - adult, Prodigy (August 2007)
  5. Bartlett JG; Is activity against "atypical" pathogens necessary in the treatment protocols for Clin Infect Dis. 2008 Dec 1;47 Suppl 3:S232-6.
  6. Rudan I, Boschi-Pinto C, Biloglav Z, et al. Epidemiology and etiology of childhood pneumonia. Bull World Health Organ 2008; 86:408.
  7. Harris M, Clark J, Coote N, et al. British Thoracic Society guidelines for the management of community acquired pneumonia in children: update 2011. Thorax 2011; 66 Suppl 2:ii1.
  8. Margolis P, Gadomski A. The rational clinical examination. Does this infant have pneumonia? JAMA 1998; 279:308.
  9. Fiore AE, Shay DK, Broder K, et al. Prevention and control of seasonal influenza with vaccines: recommendations of the Advisory Committee on Immunization Practices (ACIP), 2009. MMWR Recomm Rep 2009; 58:1.
  10. Jokinen C, Heiskanen L, Juvonen H, et al. Incidence of community-acquired pneumonia in the population of four municipalities in eastern Finland. Am J Epidemiol 1993; 137:977.

Media References

  1. PneumonisWedge09, CC BY-SA 3.0

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