Pneumonia

An acute infection of the lung parenchyma, pneumonia often impairs gas exchange. The prognosis is generally good for people who have normal lungs and adequate host defenses before the onset of pneumonia; however, pneumonia is the sixth leading cause of death in the United States.

Often pneumonia begins after an upper respiratory tract infection (an infection of the nose and throat). When this happens, symptoms of pneumonia begin after 2 or 3 days of a cold or sore throat.

Every year, more than 60,000 Americans die of pneumonia - an inflammation of the lungs usually caused by infection with bacteria, viruses, fungi or other organisms. Pneumonia is a particular concern for older adults and people with chronic illnesses or impaired immune systems, but it also can strike young, healthy people. Worldwide, it's a leading cause of death in children, many of them younger than a year old.

What are the different types of pneumonia?

The main types of pneumonia are:

• bacterial pneumonia
• viral pneumonia
• mycoplasma pneumonia

Causes

Pneumonia can be classified in several ways:

• Microbiologic etiology - Pneumonia can be viral, bacterial, fungal, protozoal, mycobacterial, mycoplasmal, or rickettsial in origin.
• Location - Bronchopneumonia involves distal airways and alveoli; lobular pneumonia, part of a lobe; and lobar pneumonia, an entire lobe.
• Type - Primary pneumonia results from inhalation or aspiration of a pathogen; it includes pneumococcal and viral pneumonia. Secondary pneumonia may follow initial lung damage from a noxious chemical or other insult (super infection), or may result from hematogenous spread of bacteria from a distant focus.

Predisposing factors

Predisposing factors for bacterial and viral pneumonia include chronic illness and debilitation, cancer (particularly lung cancer), abdominal and thoracic surgery, atelectasis, common colds or other viral respiratory infections, chronic respiratory disease (chronic obstructive pulmonary disease [COPD], asthma, bronchiectasis, cystic fibrosis), influenza, smoking, malnutrition, alcoholism, sickle cell disease, tracheostomy, exposure to noxious gases, aspiration, and immunosuppressant therapy.

Predisposing factors for aspiration pneumonia include old age, debilitation, nasogastric tube feedings, impaired gag reflex, poor oral hygiene, and decreased level of consciousness.

Signs and symptoms

In addition to the symptoms listed above, all pneumonias share the following symptoms. However, each child may experience symptoms differently. Symptoms may include:

• fever
• chest or stomach pain
• decrease in appetite
• chills
• breathing fast or hard
• vomiting
• headache
• not feeling well
• fussiness

The symptoms of pneumonia may resemble other problems or medical conditions. Always consult your child's physician for a diagnosis.

Diagnosis

Your doctor will perform a thorough physical examination, looking specifically for the telltale symptoms of pneumonia. He or she will also look at your medical history to check whether you have any underlying condition that puts you at greater risk for pneumonia. Your doctor will listen carefully to your lungs, listening for the breath sounds that indicate pneumonia. Pneumonia can be diagnosed by a number of laboratory tests, including chest x-rays, complete blood counts, blood cultures, and sputum samples. These tests can help determine what type of infection is causing the pneumonia so your doctor can plan the most effective course of treatment.

Is pneumonia contagious?

The viruses and bacteria that cause pneumonia are contagious and are usually found in fluid from the mouth or nose of an infected person. Illness can spread when an infected person coughs or sneezes on a person, by sharing drinking glasses and eating utensils, and when a person touches the used tissues or handkerchiefs of an infected person.

Treatment

Antimicrobial therapy varies with the causative agent. Therapy should be reevaluated early in the course of treatment.

Supportive measures include humidified oxygen therapy for hypoxia, mechanical ventilation for respiratory failure, a high-calorie diet and adequate fluid intake, bed rest, and an analgesic to relieve pleuritic chest pain. Patients with severe pneumonia on mechanical ventilation may require positive end­expiratory pressure to facilitate adequate oxygenation.

Prevention

You usually don't "catch" pneumonia from someone else. Instead, you develop the disease because your immune system is temporarily weakened, often for no known reason. The following suggestions can help keep you healthy:

• Don't smoke. Tobacco damages your lung's ability to ward off infection.
• Take care of yourself. Proper rest and a diet rich in fruits, vegetables and whole grains along with moderate exercise can help keep your immune system strong.
• Protect others from infection. If you have pneumonia, try to stay away from anyone with a compromised immune system. When that isn't possible, you can help protect others by wearing a face mask and always coughing into a tissue.
• Wear a mask when cleaning dusty or moldy areas.