Hospital-acquired pneumonia is an infection of the lungs contracted during a hospital stay.

Pneumonia is a very common illness. It is caused by many different germs and can range in seriousness from mild to life-threatening.

Hospital-acquired pneumonia tends to be more serious, because a patient's defense mechanisms against infection are often impaired during a hospital stay. In addition, the types of germs present in a hospital are frequently more dangerous than those encountered in the community. Hospital-acquired pneumonia occurs more commonly in patients who require a respirator to help them breathe. It is also known as ventilator-associated pneumonia.

Risk factors for hospital-acquired pneumonia include:

• Alcoholism
• Being on a breathing machine
• Immunosuppression from medications or disease
• Inhaling material into the lungs (aspiration)
• Older age
• Recent illness

• Cough that may produce mucus-like, greenish, or pus-like sputum
• Chills
• Shortness of breath
• Fever
• Easy fatigue
• Sharp or stabbing chest pain that gets worse with deep breathing or coughing
• Headache
• Loss of appetite
• Nausea and vomiting
• General discomfort, uneasiness, or ill feeling (malaise)
• Joint stiffness and joint pain (rare)
• Muscle stiffness (rare)
• Excessive sweating (rare)

A physical examination reveals respiratory distress and crackles or decreased breath sounds when listening to the chest with a stethoscope.

Tests performed may include:

• Chest x-ray or CT scan
• Sputum gram stain
• Sputum culture
• Blood cultures
• CBC (complete blood cell count)
• Arterial blood gases

The objective of treatment is to cure the infection with antibiotics. An antibiotic is selected based on the specific germ detected by sputum culture. However, the organism cannot always be identified with tests, so antibiotic therapy is given to fight the most common bacterial organisms that infect hospitalized patients -- Staphylococcus aureus and gram-negative rods.

Supportive treatment includes supplemental oxygen and lung treatments to loosen and remove thick secretions from the lungs.

Most patients respond to the treatment and improve in 2 weeks. However, hospital-acquired pneumonia can be very severe and sometimes deadly.

Elderly or debilitated patients who fail to respond to treatment may die from acute respiratory failure.

Ongoing prevention programs to limit hospital-acquired infections are in place at most institutions.

American Thoracic Society. Guidelines for the management of adults with hospital-acquired, ventilator-associated, and healthcare-associated pneumonia. Am J Respir Crit Care Med. 2005 Feb 15;171(4):388-416.