Hyperventilation syndrome

In psychiatry, hyperventilation syndrome (HVS) is an episodic disorder that often presents with chest pain and a tingling sensation of the fingertips (paresthesia) and around the mouth, as well as deep and labored breathing (causing hyperventilation), although chronic but subtle hyperventilation can cause these symptoms too.

HVS can be part of a panic attack but, despite all the stigma, most people are not putting on a show but are in true distress.

People with HVS feel like they can't get enough air, but the opposite is actually true: they have too much oxygen and too little carbon dioxide in their blood. The hyperventilation is self-promulgating as rapid breathing causes carbon dioxide (CO₂) levels to fall, and respiratory alkalosis (high blood pH) develops. This makes the symptoms worse, which causes the person to try breathing even faster, which further exacerbates the problem.

The respiratory alkalosis leads to changes in the way the nervous system fires and leads to the paresthesia, dizziness, and perceptual changes that often accompany this condition.

Other mechanisms may also be at work, and some people are physiologically more susceptible to this phenomenon than others.^[1]

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Risk factors

Many people with panic disorder or agorophobia will experience HVS. However, most people with HVS do not have these disorders.^[1]

Diagnosis

Hyperventilation syndrome is a remarkably common cause of dizziness complaints. About 25% of patients who complain about dizziness are diagnosed with HVS.^[2] The gold-standard diagnostic technique is to have the patient breathe rapidly for two minutes. This will trigger the symptoms and convince the patient that overbreathing is responsible for the symptoms. This test can only be performed at a time when the patient is not already experiencing symptoms.

Treatment

A rapid traditional intervention is to have the patient breathe into a paper bag, causing rebreathing and restoration of CO₂ levels. Some physicians do not advise the paper bag rebreathing method (or limiting its use to one or two minutes) due to the possibility of inhaling too much carbon dioxide.

The same benefits can be obtained more safely from deliberately slowing down the breathing rate by counting or looking at a the second hand on a watch. This is often referred to as "7-11 breathing", because a gentle inhalation is stretched out to take 7 seconds (or counts), and the exhalation is slowed to take 11 seconds.

Most patients benefit from carefully, deliberately slowing down their breathing twice a day for five minutes at a time.^[2] The goal is to reduce breathing to no more than five breaths per minute. This helps retrain their habits and convince them that faster breathing is unnecessary.

Acupuncture has recently been proposed as a treatment.^[3]

Causes

Most cases are caused by anxiety or stress. However, medical conditions such as infection, blood loss, heart attack,^[4] hypocapnia or alkalosis due to chemical imbalances, decreased cerebral blood flow, and increased nerve sensitivity may also underlie this symptom.^[2]

See also

• Da Costa's syndrome

References