Definition of Primary alveolar hypoventilation:

Primary alveolar hypoventilation is a rare disorder of unknown cause in which a person does not take enough breaths per minute. The lungs and airways are normal.

Causes, incidence, and risk factors:

The cause is unknown. Current research is looking at how the brains of persons with this disease may be less responsive to carbon dioxide.

The disease primarily affects men 20 to 50 years old. It can also be present in male children.

Symptoms:

Often patients themselves do not complain of being short of breath during the day. Symptoms are usually worse during sleep, and periods of apnea (episodes of stopped breathing) are usually present. Patients with this disease are extremely sensitive to even small doses of sedatives or narcotics, which can make their already inadequate breathing much worse.

Symptoms include:

• Bluish coloration of the skin caused by lack of oxygen
• Daytime drowsiness
• Fatigue
• Lethargy
• Morning headaches
• Swelling of the ankles
• Waking up from sleep unrested
• Waking up many times at night

Signs and tests:

The health care provider will perform a physical exam. Tests will be done to rulle out other causes. For example, muscular dystrophy can make the rib muscles weak, and emphysema damages damaging the lung tissue itself. A a small stroke can affect the breathing center in the brain.

Tests that may be done include:

• Blood gases
• Chest x-ray
• Hematocrit
• Lung function tests
• Overnight oxygen leven measurements (oximetry)
• Serum bicarbonate
• Sleep study (polysomnography)

Treatment:

Medications that stimulate the respiratory system may be used but do not always work. Mechanical devices that assist breathing, particularly at night, may be helpful in some patients. Oxygen therapy may be helpful in a few patients, but may cause worse night symptoms in others.

Expectations (prognosis):

Response to treatment varies.

Complications:

A possible complication is cor pulmonale (right-sided heart failure).

Calling your health care provider:

Call for an appointment with your health care provider if symptoms of this disorder develop. Seek urgent medical care if bluish skin (cyanosis) occurs.

Prevention:

There is no known prevention. Patients should avoid using sleeping medications or other medications that may cause drowsiness.