Clinical features:
(1) The age of onset is usually after 50 years of age.
(2) The syndrome tends to be more common in women.
(3) The headaches occur only during sleep and can occur during naps.
(4) The headaches tend to occur at a consistent time.
(5) The headaches can occur up to 3 times in a single night.
(6) The headaches tend to occur >= 15 times a month.
(7) The pain will waken the person.
(8) The pain persists >= 15 minutes after waking, and can last up to 3 hours.
(9)The pain resolves spontaneously.
(10) The pain may be localized or generalized.
(11) Autonomic signs are usually absent (but may occur with severe headaches).
(12) The patient may experience nausea, photophobic and phonophobia but these are usually absent.
Differential diagnosis: cluster headaches
The headaches may respond to
(1) lithium
(2) caffeine at bedtime
(3) verapamil
(4) indomethacin
(5) flunarizine
