Belching, Air Swallowing, and Hiccups

Slide 5.

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Hiccups (singultus) can be the tip of the iceberg of pathophysiology that might be causing this symptom, so hiccups should alert you that something might be awry.

Hiccups are a common reflex caused by a spasm of the diaphragm and intercostal muscles, typically a unilateral spasm of the diaphragm on the left side, but it can be bilateral. The spasm is triggered anywhere along the reflex arch that includes the afferent vagal, phrenic, and sympathetic nerves, with central processing in the brainstem and efferent signaling to the respiratory muscles. Therefore, anything that creates an irritation along this pathway can result in hiccups.

Hiccups are considered persistent if they last for 48 hours and intractable if they last longer than 1 month. In a patient with persistent or intractable hiccups, think about cardiac, thyroid, gastrointestinal, or gastroesophageal reflux disease. We see hiccups in the intensive care unit in patients with prolonged recumbency and reflux disease. Many factors can cause inflammation or compression of the phrenic nerve, and all of these factors should be considered, along with a central nervous system evaluation.

The work-up of patients with hiccups should include a good history and consideration of signs and symptoms that may point you in a certain direction if there was a precipitating event. Sometimes people will experience hiccups after anesthesia induction or another intervention. Those tend to be transient and not intractable or persistent.

From a gastrointestinal perspective, endoscopy might be indicated. Impedance pH monitoring may be helpful in looking for reflux disease. In a focused central nervous system evaluation, MRI of the brainstem helps to rule out central nervous system lesions that could trigger hiccups.