Pneumonia - Diagnosis

Highlights	Risk Factors	Prevention
Introduction	Diagnosis	Resources
Causes	Treatment	References
Symptoms	Medications
Prognosis	Surgery

Diagnosis

Diagnostic Difficulties in Community-Acquired Pneumonia (CAP). It is important to determine if the cause of CAP is bacteria, atypical bacteria, or a virus, since they all require different treatments. In children, for example, S. pneumonia is the most common cause, but respiratory syncytial virus may also cause the disease. Although symptoms may differ, they often overlap, which can mak it difficult to identify the organism by symptoms alone.

Nevertheless, in many cases of mild-to-moderate community-acquired pneumonia, the physician is able to diagnose and treat pneumonia based solely on a history and physical examination.

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Diagnostic Difficulties in Hospital-Acquired (Nosocomial) Pneumonia. Diagnosing pneumonia is particularly difficult in hospitalized patients for a number of reasons:

Many hospitalized patients have similar symptoms, including fever or signs of lung infiltration on x-rays.
In hospitalized patients, sputum or blood tests often indicate the presence of bacteria or other organisms, but such agents do not necessarily indicate pneumonia.

Doctors making a diagnosis of pneumoniashould rule out other conditions, using a chest x-ray, two sets of blood cultures, a urine analysis for Legionella, and a lung fluid sample, among other tests.

Medical and Personal History

The patient's history is an important part of the diagnosis of pneumonia. The patient should be sure to report any of the following:

Recent or chronic respiratory infection
Exposure to people with pneumonia or other respiratory illnesses (such as tuberculosis)
History of smoking
Alcohol or drug abuse
Recent travel
Occupational risks

Physical Examination

Use of the Stethoscope. The most important diagnostic tool for pneumonia is the stethoscope. Sounds in the chest that may indicate pneumonia are the following:

Rales (a bubbling or crackling sound). Rales on one side of the chest and rales heard while the patient is lying down are strongly suggestive of pneumonia.
Rhonchi (abnormal rumblings indicating the presence of thick fluid).
Percussion. The physician will also use a test called percussion, in which he or she taps the chest lightly. A dull thud, instead of a healthy hollow-drum-like sound, indicates certain conditions that suggest pneumonia. These conditions include including consolidation (a condition in which the lung becomes firm and inelastic), and pleural effusion (fluid build-up in the space between the lungs and the lining around it).