PNEUMONIA Definition of the Disease Pneumonia is a form of acute respiratory infection that affects the lungs.

The lungs are made up of small sacs called alveoli, which fill with air when a healthy person breathes. When an individual has pneumonia, the alveoli are filled with pus and fluid, which makes breathing painful and limits oxygen intake. Causes Pneumonia is caused by a number of infectious agents, including viruses, bacteria and fungi. The most common are:

Streptococcus pneumoniae the most common cause of bacterial pneumonia in children; Haemophilus influenzae type b (Hib) the second most common cause of bacterial pneumonia; respiratory syncytial virus is the most common viral cause of pneumonia; in infants infected with HIV, Pneumocystis jiroveci is one of the commonest causes of pneumonia, responsible for at least one quarter of all pneumonia deaths in HIV-infected infants.

Risk Factors While most healthy children can fight the infection with their natural defences, children whose immune systems are compromised are at higher risk of developing pneumonia. A child's immune system may be weakened by malnutrition or undernourishment, especially in infants who are not exclusively breastfed. Pre-existing illnesses, such as symptomatic HIV infections and measles, also increase a child's risk of contracting pneumonia. The following environmental factors also increase a child's susceptibility to pneumonia: indoor air pollution caused by cooking and heating with biomass fuels (such as wood or dung) living in crowded homes parental smoking.

Signs and Symptoms Most people who develop pneumonia initially have symptoms of a cold (upper respiratory infection, for example, sneezing, sore throat, cough), which are then followed by a high fever (sometimes as high as 104 F), shaking chills, and a cough with sputum production. The sputum is usually discolored and sometimes bloody. Depending on the location of the infection, certain symptoms are more likely to develop. When the infection settles in the air passages, cough and sputum tend to predominate the symptoms. In some, the spongy tissue of the lungs that contain the air sacs is more involved. In this case, oxygenation of the blood can be impaired, along with stiffening of the lung, which results in shortness of breath. At times, the individual's skin color may change and become dusky or purplish (a condition known as "cyanosis") due to their blood being poorly oxygenated. When pneumonia becomes severe, children may experience lower chest wall indrawing, where their chests move in or retract during inhalation (in a healthy person, the chest expands during inhalation). Very severely ill infants may be unable to feed or drink and may also experience unconsciousness, hypothermia and convulsions. Diagnostic and Laboratory Procedures Pneumonia may be suspected when the doctor examines the patient and hears coarse breathing or crackling sounds when listening to a portion of the chest with a stethoscope. There may be wheezing or the sounds of breathing may be faint in a particular area of the chest. A chest X-ray is usually ordered to confirm the diagnosis of pneumonia. The lungs have several segments referred to as lobes, usually two on the left and three on the right. When the pneumonia affects one of these lobes, it is often referred to as lobar pneumonia. Sputum samples can be collected and examined under the microscope. Pneumonia caused by bacteria or fungi can be detected by this examination. A sample of the sputum can be grown in special incubators, and the offending organism can be subsequently identified. It is important to understand that the sputum specimen must contain little saliva from the mouth and be delivered to the laboratory fairly quickly. Otherwise, overgrowth of noninfecting bacteria from the mouth may predominate. As we have used antibiotics in a broader uncontrolled

fashion, more organisms are becoming resistant to the commonly used antibiotics. These types of cultures can help in directing more appropriate therapy. A blood test that measures white blood cell count (WBC) may be performed. An individual's white blood cell count can often give a hint as to the severity of the pneumonia and whether it is caused by bacteria or a virus. An increased number of neutrophils, one type of WBC, is seen in most bacterial infections, whereas an increase in lymphocytes, another type of WBC, is seen in viral infections, fungal infections, and some bacterial infections (like tuberculosis). Bronchoscopy is a procedure in which a thin, flexible, lighted viewing tube is inserted into the nose or mouth after a local anesthetic is administered. Using this device, the doctor can directly examine the breathing passages (trachea and bronchi). Simultaneously, samples of sputum or tissue from the infected part of the lung can be obtained. Medical Managament Antibiotics often used in the treatment of this type of pneumonia include penicillin, amoxicillin and clavulanic acid (Augmentin, Augmentin XR), and macrolide antibiotics including erythromycin (E-Mycin, Eryc, Ery-Tab, PCE, Pediazole, Ilosone), azithromycin (Zithromax, Z-Max), and clarithromycin(Biaxin). Penicillin was formerly the antibiotic of choice in treating this infection. With the advent and widespread use of broader-spectrum antibiotics, significant drug resistance has developed. Fungal infections that can lead to pneumonia include histoplasmosis, coccidiomycosis, blastomycosis, aspergillosis, and cryptococcosis. These are responsible for a relatively small percentage of pneumonias in the United States. Each fungus has specific antibiotic treatments, among which are amphotericin B, fluconazole (Diflucan), penicillin, and sulfonamides. Health Teachings

Sources

WHO. (2012). Pneumonia. Retrieved September 22, 2012, from http://www.who.int/mediacentre/factsheets/fs331/en/index.html Schiffman, G. (2011). Pneumonia. Retrieved September 22, 2012, from http://www.medicinenet.com/pneumonia/page4.htm