Several types of headaches are unique to sleep and its disorders. Thus, evaluation of headache should also include temporal information during the 24-hour cycle, which may offer clues to the diagnosis. Key headaches that are classically associated with sleep include cluster headaches, migraines, chronic paroxysmal hemicrania, and hypnic headaches. Additionally, sleep apnea can help trigger headaches, in particular.
Description of Headaches
Cluster headaches are characterized by unilateral severe headache of rapid onset (5-15 minutes) and short duration (30-45 minutes) with autonomic changes in 97% of the cases. Autonomic changes are attributed to involvement of the carotid sympathetic plexus in the cavernous sinus. Symptoms include a unilateral Horner’s syndrome, lacrimation, and injection of the conjunctiva of one eye. A link to rapid eye movement sleep is considered characteristic. More recent studies suggest a link to obstructive sleep apnea and hypoxemia and raise the possibility that the sleep disordered breathing, which is often worse during rapid eye movement sleep, may be the etiology of the association with rapid eye movement sleep (rather than rapid eye movement sleep itself).
More recent studies suggest a link to obstructive sleep apnea and hypoxemia and raise the possibility that the sleep disordered breathing, which is often worse during rapid eye movement, may be the etiology of the association with rapid eye movement sleep (rather than rapid eye movement itself).
Migraine headaches are neurovascular headaches that may result from inflammation of the trigeminovascular system with secondary vasodilatation and throbbing pain. Headaches are more often unilateral than bilateral. Nausea and photophobia is common. Aura occurs in 20% and, when present, results from a slow march of neurologic symptoms across the affected region due to vasodilatation and secondary vasoconstriction. Common triggers include stress, sleep deprivation, excess sleep, menses, weather changes, chocolate, and alcohol. Exercise is exacerbating. Fifty percent occur during sleep, from 4 a.m. to 9 a.m. An association with rapid eye movement and stage non-rapid eye movement N3 (stages 3 and 4) sleep is reported. One must be careful to check for the presence of sleep-disordered breathing as the initial cause as obstructive sleep apnea may lead to “pseudo sleep-related migraine” that becomes repetitive due to inappropriate prescription of an antimigraneous treatment.
Chronic paroxysmal hemicrania is rare and more common in females than males. Similar to cluster headaches, pain is unilateral and can be stabbing, pulsatile, or throbbing in nature. Autonomic symptoms such as lacrimation, ptosis, conjunctival injection, and nasal congestion are common. Headaches are more frequent than in cluster headaches, occurring from 1 to 40 times per day with duration on the order of minutes to two hours. A strong association with rapid eye movement sleep is evident.
Hypnic headaches are strictly related to sleep and cause awakening at the same time each night. Pain is more often bilateral than unilateral. The duration is typically 5 to 15 minutes, and the frequency is at least 15 times in one month. They tend to occur during rapid eye movement sleep.
Headaches associated with obstructive sleep apnea commonly occur in the morning on awakening and are distinct from migraine headaches. Some debate exists on whether or not the actual association is to disrupted sleep, rather than sleep apnea itself [reviewed in]. Assuming the latter association, mechanisms proposed for headache in obstructive sleep apnea include vasodilatation secondary to hypoxemia and hypercapneic vasodilatation, autonomic and blood pressure surges, and increased intracranial pressure during the apneas (see above for issues with migraine).
Evaluation of Headaches
Evaluation should begin with a neurologic diagnosis of the headache syndrome. Once diagnosed, standard neurologic interventions are implemented according to the latest clinical guidelines for the type of headache. A sleep and headache diary may be helpful if the above headache disorders are suspected. Once one of the above types of headaches is diagnosed, given the increased association with sleep apnea, a polysomnogram is warranted.
Treatment of Headaches
Nonpharmacologic treatments include standard methods to treat any underlying sleep disorder determined on polysomnogram. If the sleep diary and headache logs reveal a pattern associated with excess sleep or sleep deprivation, modifying the patient’s sleep schedule may be used to decrease occurrence. If sleep apnea is present, a headache diary and sleep may be helpful to monitor response to treatment and enable reduction of medications. If certain foods or beverages are triggers in an individual patient, they should be avoided as well. Withdrawal from inappropriate headache treatment may be needed.
Pharmacologic treatments are directed to the standard treatments currently available for each type of headache. In this regard, cluster headaches respond well to oxygen, triptans, dihydroergotamine (DHE), lidocaine, and butorphanol, acutely. Prophylactic treatments include verapamil, methysergide, divalproex sodium, lithium, topiramate, and baclofen. Migraines are treated with preventive as well as abortive agents. Abortive treatments include aspirin, acetaminophen, aspirin plus caffeine, non-steroidal anti-inflammatory drugs (NSAIDS), triptans, DHE, opioid nasal sprays and ergotamine. Prophylactic agents include tricyclic antidepressants, β-blockers, and anticonvulsants. Chronic paroxysmal hemicrania is very responsive to indomethacin. Alternative treatments may include aspirin, verapamil, steroids, and naproxen. Treatments for hypnic headaches include caffeine, lithium, indomethacin, atenolol, cyclobenzaprine, melatonin, prednisone, and flunarizine.