Neuro Disorders: Hypnic Headache

Hypnic Headache is a type of primary headache condition and it occurs when somebody is sleeping.

A primary headache is one that occurs without any known structural brain pathologies as well as any type of systemic causes. What exactly triggers this headache or what neuro chemicals are involved is still unknown.

Sleep studies indicate that this headache is somehow related with the REM (rapid eye movement) sleep dysfunction.

The episodes typically occur during sleep and wake the patient up. The duration ranges from about 15 minutes to few hours. The nature of the headache varies including throbbing, stabbing, dull pressure like etc. The severity varies too, from mild to moderate to intense. Usually it involves the fronto-temporal region. These attacks generally occur around the same time in the night for a particular patient, and between one and three am pattern is seen for may patients.

Symptoms common with migraine type headache like nausea, vomiting, light and sound bothering, auras etc are not seen with this headache. Also autonomic manifestations like reddening of the eye, eye lid swelling, forehead flushing, pupil size changes, abnormal tear and nasal secretions that are seen for example with cluster headache are not seen with this one.

It is mostly seen in older people (around age 60) although there are variants that tend to occur at younger people too. Women are generally affected more than men and this is usual for majority of the primary headache syndromes.

This is a primary headache as mentioned above so we do not expect to see any abnormalities to explain the headache. Having said that investigations like a CT or MRI of the brain with and without contrast are generally required since night time headache can occur in many other settings including structural brain problems like tumor etc.

Another headache common to older people is temporal arteritis, so along with a clinical evaluation ESR/CRP may also be required.

The acute headache episodes may be treated with some NSAID like indomethacin, Tylenol etc. If episodes are frequent then a preventive agent is required and medications like lithium, verapamil, flunarizine etc can be tried.

Lithium can be started at low doses like 100 to 300 mg, at this dose generally this medication is tolerated well.

Some studies have shown that caffeine taken prior to sleep may also be effective for this type of headache however the beneficial effect may be countered by the insomnia it generally causes.

A neurologist is frequently involved in the care of patients with Hypnic Headache.