When a recent patient described hearing an intense noise that woke him from sleep, it wasn’t clear to me at first what he was experiencing. He described the experience as terrifying, but not painful.

The patient underwent MRI, but nothing unusual had been found. He did have a history of selective serotonin reuptake inhibitor (SSRI) use and had recently been weaned from the medication.

Patients sometimes report feeling “brain zaps” or electrical sensations when being weaned from SSRIs. At first I thought he may be experiencing this side effect, but as he continued to describe his situation, I was not convinced SSRI use was to blame. He had no other withdrawal symptoms and said the episode occurred as he was trying to fall asleep.

Exploding head syndrome (EHS) is very rare. I can’t say for sure that my patient actually has it, as he has only experienced symptoms on one occasion. However, his description seems to fit the syndrome. EHS is named after the sound patients with the disorder perceive hearing. Patients with EHS will complain of a severe noise that usually occurs when transitioning from wakefulness to sleep, although it has been recorded by polysomnogram in all sleep stages.

Patients may describe EHS symptoms as hearing a gunshot, an explosion, a bomb going off, a clash of cymbals, or thunder that awakens them from sleep. It is often accompanied by shortness of breath and increased heart rate. The cause is unknown, but etiology appears benign.

EHS episodes last for seconds and have a random pattern. Some patients may experience the symptoms several times and then never experience the problem again. For others, episodes can be quite frequent.

EHS does not cause pain, but it does cause anxiety and fear, as patients often believe something so intense must be serious. Some patients have described seeing flashes of light when the sound occurs. One theory is that EHS could be a manifestation of seizure activity.

Because EHS is benign, treatment is mostly reassurance; however, any other potential cause of the symptoms should be ruled out. Some patients have reported benefiting from clomipramine or nifedipine, but EHS symptoms often decline after patients understand that the illness is benign.

In medicine we are often taught to think of horses not zebras. This case was a reminder that sometimes it is appropriate to look in the zoo. If you are making a diagnosis and you have lingering questions, follow your intuition and investigate further.

Sharon M. O’Brien, MPAS, PA-C, works at Presbyterian Sleep Health in Charlotte, N.C. Her main interest is helping patients understand the importance of sleep hygiene and the impact of sleep on health.