Pneumonia (cont.)

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How is pneumonia diagnosed?

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. Some pneumonias have a more patchy distribution that does not involve specific lobes. In the past, when both lungs were involved in the infection, the term "double pneumonia" was used. This term is rarely used today.

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 (cultured), 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.

Sometimes, fluid collects in the pleural space around the lung as a result of the inflammation from pneumonia. This fluid is called a pleural effusion. If a significant amount of fluid develops, it can be removed in a procedure known as a thoracentesis. After numbing the skin with local anesthetic a needle is inserted into the chest cavity and fluid can be withdrawn and examined under the microscope by a pathologist. Often ultrasound is used to prevent complications from this procedure. In some cases, this fluid can become severely inflamed (parapneumonic effusion) or infected (empyema) and may need to be removed by more aggressive surgical procedures. Today, most often, this involves surgery through a tube or thoracoscope. This is referred to as video-assisted thoracoscopic surgery or VATS.

Medically Reviewed by a Doctor on 3/22/2013

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