Pneumonia is an acute inflammation of the lungs caused by infection. Pneumonia is a very common disease and cut across all ages. It could have a dramatic and bizarre presentation in the extreme of ages.
Pneumonia is the leading cause of death in children worldwide. Pneumonia kills an estimated 1.1 million children under the age of five annually. The respiratory tract is exposed to the atmosphere. To prevent infection, the airways have some inbuilt defence mechanism. The presence of some antibodies like IgA and IgG and anti-inflammatory effect of surfactant present in the respiratory tract protects the respiratory tract against infection.
A cough is a relax mechanism that helps to clear the airways of foreign body and secretions from the upper and the lower respiratory tract. The presence of cilia in the airways helps to filter the air as it goes through the airways into the lungs. Infection result when there is the breakdown in this defence mechanism.
The upper airway and oropharynx are colonized by some pathogens referred to as normal body flora rendered harmless by host defences. However, they can cause infection when the host immunity is compromised. Infection develops when the pathogen is inhaled or aspirated or reach the lungs via the bloodstream or contagious spread overcome the multiple host defence mechanism.
Pneumonia can be caused by bacteria, virus, fungi and parasite.
i. Bacteria: The following bacteria are common bacteria responsible for pneumonia: Streptococcus pneumonia, Staphylococcus Aureus, Hemophilus Influenza etc.
ii. Virus: Respiratory syncytia virus, Adenovirus, Influenza virus etc.
iii. Fungi: The common fungi pathogens include: Histoplasma Capsuslatum,
iv. Parasites: Paragonimus Westermani and Toxocera Canis are most Prominent.
2. Risk factors for pneumonia include:
i. Cigarette smoking
ii. Chronic Lung Disease
v. Brain injury
vi. Immune system problem HIV/AIDS
vii. Treatment for cancer.
viii. Other serious diseases like heart disease
ix. Diabetes mellitus
x. Prolonged bed rest
3. Signs and Symptoms:
The symptoms include:
iii. A cough
A cough is always dry in infants and usually dry at onset in adult, but later productive of rusty yellowish sputum, chest pain usually localized to the area of the lungs affected.
Pneumonia may manifest as upper abdominal pain especially when the lower lobe of the infected lungs irritates the diaphragm.
Symptoms become variable at the extreme of age. Infection in infants may manifest as non-specific irritability and restlessness; in the elderly, as confusion and obtundation. When sputum contains blood TB Pneumonia must be suspected.
The Sign includes:
ii. Fast heartbeat.
The chest will be dull to percussion over the area of the lungs affected, bronchial breath sounds and crackles are hard at auscultations during resolution. Cyanosis is common in the infant; fever may not be present in the elderly.
Diagnosis of Pneumonia is suspected based on clinical findings and confirmed by investigation. Chest X-ray, PVC, full blood count; sputum culture may not yield an organism in more than 50% of cases. Electrolyte and urea, blood culture especially patient who acquire the disease after prolonged hospital admission.
The treatment of pneumonia can be done on outpatient bases in mild cases. In the severe case, in the very young and the very old, hospital admission is required. The use of appropriate antibiotics, analgesic and other supportive therapy like intravenous infusion and oxygen may be necessary.
i. Pneumonia may result in pleura effusion (accumulation of fluid in the chest cavity).
ii. Lung accesses can also result especially when pneumonia complicates aspiration.
The outcome of treatment is usually very good. Patient on outpatient treatment should show appreciable improvement over 24-72 hours. Patients on admission always show signs of rapid improvement if there is no morbidity.
Death may occur from pneumonia itself, progress to septicemia or from co-morbidity. Aspiration is a major risk factor for death, especially in the older age group.