Nighttime Headaches after Age 50

In April 2016, Headache: The Journal of Head and Face Pain published the results of the largest study to date on a rare primary headache disorder called Hypnic Headache. Initial onset begins late in life, usually after age 50. It is characterized by headache pain that wakes the patient in the middle of the night, typically between 1:00 am and 5:30 am. The attack lasts for at least 15 minutes. Although the ICHD-3 criteria limit duration to not more than 4 hours, the recent study found that attacks can last up to 8 hours. Most often the pain resembles that of a tension-type headache, but migraine-like symptoms do occur in 22% of patients.

Differential Diagnosis

Nighttime headaches can occur for several reasons, so imaging studies and other medical tests are required to rule out secondary causes such as sleep apnea, hypertension, hypoglycemia, medication overuse, intracranial disorders, or even cervicogenic headaches.  Other primary headache disorders can cause nighttime headaches, too.

Sleep apnea often causes headaches upon waking that resemble tension-type headaches. Untreated sleep apnea can also be a migraine trigger. A sleep study is required to confirm a suspected case of sleep apnea. Treatment with CPAP resolves this symptom.

Cervicogenic headaches are common in older patients due to cervical degenerative disc disease. Poor neck position while sleeping can create added pressure that triggers referred pain from the neck up into the head. Nerve blocks frequently resolve referred headache pain due to this problem.

Cluster headaches often wake patients several times each night. For this reason both Hypnic Headache and Cluster Headache have been referred to as “alarm-clock headaches”. However, Hypnic Headache does not usually involve autonomic symptoms such as tearing, redness, or swelling of the eye or nasal congestion. These symptoms have been reported in only 5% of patients studied. Age of onset and location of the pain are key differentiators. Cluster Headache usually begins prior to age 30, where Hypnic Headache starts after age 50. Plus, the pain of Hypnic Headache is typically felt on both sides of the head. In contrast, cluster headache occurs only on one side of the head. Another similarity is that the attacks of both headache disorders are improved by movement. It has been hypothesized that Hypnic Headache may eventually prove to be a Trigeminal Autonomic Cephalalgia, along with Cluster Headache, Hemicrania Continua, Paroxysmal Hemicrania, SUNCT, and SUNA.

Migraine is often triggered by sleep disorders and disturbances, so it’s not unusual for patients with Migraine to experience nighttime attacks. Researchers acknowledged that differentiating Migraine from Hypnic Headache can be very difficult. Often a trial of medication is necessary to confirm or rule out the diagnosis. When nighttime headaches do not respond to typical Migraine prophylactics and the patient presents with initial onset after age 50, it is reasonable to suspect Hypnic Headache.

Treatment

Although rare, Hypnic Headache can seriously impact quality of life. It is often prolonged for many years and can result in frequent attacks. Most of the time, attack frequency resembles that of Chronic Migraine, occurring nearly every day. Preventive treatment is essential to reduce the pain and suffering brought on by Hypnic Headache.

The most effective treatment for Hypnic Headache is lithium, most commonly prescribed at 300 mg before bedtime. 70% of patients studied using this preventive saw total remission within 2 months. Another 20% experienced significant reduction in frequency and severity. Unfortunately, lithium can cause some pretty serious side effects so patients must be monitored carefully with regular blood tests to check for possible lithium toxicity.

The second most effective treatment is caffeine. While it seems illogical, patients with Hypnic Headache actually report improved sleep quality when taking caffeine before bedtime. They also report no difficulty falling asleep after consuming caffeine at the onset of an attack. Most patients using this treatment drink a caffeinated beverage, while fewer took a caffeine-containing medication such as No-Doz.

Other treatments that may be tried are Botox, lamotrigine, and hypnotics such as diphenhydramine.

ICHD-3 Diagnostic Criteria

Previously used terms: Hypnic headache syndrome; ‘alarm clock’ headache'.

Description:  Frequently recurring headache attacks developing only during sleep, causing wakening and lasting for up to 4 hours, without characteristic associated symptoms and not attributed to other pathology.

Diagnostic criteria:

1. Recurrent headache attacks fulfilling criteria B-E
2. Developing only during sleep, and causing wakening
3. Occurring on ≥10 days per month for >3 months
4. Lasting ≥15 minutes and for up to 4 hours after waking
5. No cranial autonomic symptoms or restlessness
6. Not better accounted for by another ICHD-3 diagnosis.

Comments: Hypnic Headache usually begins after age 50 years, but may occur in younger people. The pain is usually mild to moderate, but severe pain is reported by one-fifth of patients. Pain is bilateral in about two-thirds of cases. Attacks usually last from 15 to 180 minutes, but longer durations have been described. Most cases are persistent, with daily or near daily headaches, but an episodic subform (on less than 15 days per month) may occur. Although it was thought that the features of Hypnic Headache were generally tension-type-like, recent studies found that patients could present with Migraine-like features and some patients had nausea during attacks.

Onset of Hypnic Headache is probably not related to sleep stage. A recent MRI study showed grey matter volume reduction in the hypothalamus in patients with Hypnic Headache. Lithium, caffeine, melatonin and indomethacin have been effective treatments in several reported cases. Distinction from one of the subtypes of Trigeminal Autonomic Cephalalgias, especially Cluster Headache, is necessary for effective management. Other possible causes of headache developing during and causing wakening from sleep should be ruled out, with particular attention given to sleep apnoea, nocturnal hypertension, hypoglycaemia and medication overuse; intracranial disorders must also be excluded. However, the presence of sleep apnoea syndrome does not necessarily exclude the diagnosis of Hypnic Headache.