Hyperventilation syndrome is anxiety-related dyspnea and tachypnea often accompanied by systemic symptoms.
Hyperventilation syndrome most commonly occurs among young women but can affect either sex at any age. It is sometimes precipitated by emotionally stressful events. Hyperventilation syndrome is separate from panic disorder (see Anxiety Disorders: Panic Attacks and Panic Disorder), although the 2 conditions overlap; about half of patients with panic disorder have hyperventilation syndrome and one quarter of patients with hyperventilation syndrome have panic disorder. It occurs in both acute and chronic forms. Chronic hyperventilation is more common; however, the acute form is easier to recognize.
Symptoms and Signs
Patients with acute hyperventilation syndrome present with dyspnea sometimes so severe that they liken it to suffocation. It is accompanied by agitation and a sense of terror or by symptoms of chest pain, paresthesias (peripheral and perioral), peripheral tetany (eg, stiffness of fingers or arms), and presyncope or syncope or sometimes by a combination of all of these findings. Tetany occurs because respiratory alkalosis causes both hypophosphatemia and hypocalcemia. On examination, patients may appear anxious, tachypneic, or both; lung examination is unremarkable.
Patients with chronic hyperventilation syndrome present far less dramatically and often escape detection; they sigh deeply and frequently and often have nonspecific somatic symptoms in the context of mood and anxiety disorders and emotional stress.
Hyperventilation syndrome is a diagnosis of exclusion; the challenge is to use tests and resources judiciously to distinguish this syndrome from more serious diagnoses. Basic testing includes pulse oximetry, chest x-ray, and ECG. Pulse oximetry in hyperventilation syndrome shows O2 saturation at or close to 100%. Chest x-ray is normal. ECG is done to detect cardiac ischemia, although hyperventilation syndrome itself can cause ST-segment depressions, T-wave inversions, and prolonged QT intervals. ABGs are needed when other causes of hyperventilation are suspected, such as metabolic acidosis. Occasionally, acute hyperventilation syndrome is indistinguishable from acute pulmonary embolism, and tests for pulmonary embolism (eg, d-dimer, ventilation/perfusion scanning, CT angiography) may be necessary.
Treatment is reassurance. Some physicians advocate teaching the patient maximal exhalation and diaphragmatic breathing. Most patients require treatment for underlying mood or anxiety disorders; such treatment includes cognitive therapy, stress reduction techniques, drugs (eg, anxiolytics, antidepressants, lithium), or a combination of these techniques.
Last full review/revision July 2012 by Noah Lechtzin, MD, MHS