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.A.D.A.M.

Causes, incidence, and risk factors

Normally, when the oxygen levels in the blood are low or the carbon dioxide levels are high, there is a signal from the brain to breathe more deeply or more quickly. In people with primary alveolar hypoventilation, this change in breathing does not happen.

The cause of primary alveolar hypoventilation is unknown. Some patients have a specific genetic defect.

The disease mainly affects men 20 to 50 years old, although it may also occur in children.

Symptoms

Symptoms are usually worse during sleep, and periods of apnea (episodes of stopped breathing) are usually present. Often patients themselves do not complain of shortness of breath during the day.

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

Persons with this disease are extremely sensitive to even small doses of sedatives or narcotics, which can make their already inadequate breathing much worse.

Signs and tests

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

Tests that may be done include:

• Blood gases
• Chest x-ray
• Hematocrit and hemoglobin blood tests
• Lung function tests
• Overnight oxygen level 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

The low blood oxygen level can cause high blood pressure in the lung blood vessels. This can lead to 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.

References

1. Duffin J, Phillipson EA. Hypoventilation and Hyperventilation Syndromes In: Mason RJ, Broaddus CV, Martin TR, et al. Murray & Nadel's Textbook of Respiratory Medicine. 5th ed. Philadelphia, Pa: Saunders Elsevier; 2010:chap 78.
2. Malhotra A. Disorders of ventilatory control. In: Goldman L, Schafer AI, eds. Cecil Medicine. 24th ed. Philadelphia, Pa: Saunders Elsevier;2011:chap 86.

Review Date: 8/30/2012.

Reviewed by: David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine. Denis Hadjiliadis, MD, Assistant Professor of Medicine, Division of Pulmonary, Allergy and Critical Care, University of Pennsylvania, Philadelphia, PA. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M. Health Solutions, Ebix, Inc.