A Hypnic headache is a rare, primary headache disorder that wakes people from sleep.
Hypnic headaches happen only during sleep and wake the sufferer, which is why they are sometimes referred to as alarm-clock headaches. These headaches tend to occur at the same time of night, usually between 1 and 3 a.m. and can last anywhere from 15 minutes to 4 hours after waking. They tend to affect people over the age of 50, although they may occur in younger people as well. They are frequently occurring headaches. Some people may have them several nights a week, while others experience them at least 10 times a month. The pain is often described as throbbing. It can range from mild to severe and is usually bilateral (on both sides of the head). Sometimes people may experience migraine-like symptoms including nausea, sensitivity to light and sensitivity to sounds.
There has been little research into the condition and what causes hypnic headaches. They seem to be a primary headache disorder, which means they aren’t caused by an underlying condition, such as a brain tumor. They commonly occur at the same time every night, possibly linking the headaches with circadian rhythm, but polysomnography has recently revealed that the onset of hypnic headaches may be associated with REM sleep.
Hypnic headaches are rare, and should be diagnosed only after other causes have been ruled out. Tests may include:
• Blood tests. Checking for infection, electrolyte imbalances, clotting problems, or high blood sugar levels.
• Blood pressure tests. high blood pressure, is a common cause of headaches, especially in older adults.
• Head CT scan. To examine the bones, blood vessels, and soft tissues in your head.
• Nocturnal polysomnography. Monitoring of breathing patterns, blood oxygen levels, movements, and brain activity while sleeping.
• Home sleep tests. To detect sleep apnea symptoms
• Brain MRI scan. This test that uses a magnetic field and radio waves to produce detailed images of the brain and the brain stem
• Carotid ultrasound. A painless imaging test that uses high-frequency sound waves to create images of the inside of your carotid arteries, which supply blood to your face, neck, and brain.
There are no treatments specifically designed to treat hypnic headaches. Recommended initial treatment is caffeine (in the form of cups of coffee at bedtime). For most patients, paradoxically, caffeine does not prevent patients from sleeping. Melatonin, flunarizine, topiramate, indomethacin and Lithium carbonate have been used effectively in some cases, but indomethacin is not safe for patients with a history of stomach ulcers and Lithium carbonate must be used with caution, especially in the presence of kidney disease, thyroid disease, dehydration, or use of diuretics.