Migraine

Migraine is subclassified as migraine without aura ( Table 103.1 ) and migraine with aura ( Table 103.2 ). Under ICHD-3, “chronic migraine,” which was previously classified as a migraine complication, is now also included as a migraine subtype. Individuals with headaches occurring 15+ days per month for 3 or more months and who report migraine symptoms for 8 or more days per month would qualify for a chronic migraine diagnosis. According to ICHD-3 , chronic migraine was included as a subtype because “it is impossible to distinguish the individual episodes of headache in patients with such frequent or continuous headaches,” (p. 650). About 20% of patients have aura, usually preceding the headache, which consists of focal neurologic signs or symptoms that begin gradually and fade away within 30 to 60 minutes as the headache begins. The most common type of aura involves visual disturbances, typically an enlarging scotoma, but patients can also see shapes such as stars, zigzag lines, or other visual distortions, including field cuts and photopsias. However, blurred vision is usually not considered a part of aura. Sensory or motor problems occur far less frequently. Migraine can also be classified as episodic or chronic (15 or more migraine headache days per month). With diligent record tracking, some patients are able to identify triggers for their headache, including exertion, certain foods, scents, and hormonal influences. Three gene mutations have been identified that are associated with a particular subtype of migraine with aura known as familial hemiplegic migraine. These genes influence the stability of neuronal cell membranes.

Many patients with migraine report prodromal symptoms: yawning; neck and shoulder muscle discomfort; excessive salivation; and changes in appetite, mood, sleep, gastrointestinal function, and urination. Some of these can start days before the actual headache. Postdromal symptoms in migraine include fatigue, exercise intolerance, and neck and shoulder muscle discomfort. If headaches progress untreated, 80% of patients eventually develop allodynia, defined as pain in response to stimuli that normally are nonpainful. Once allodynia develops, treatment may be less successful. In addition, there is increasing attention on cognitive symptoms of migraine that likely contribute to disability. Pain-related disability is a well-recognized target of migraine treatment, so the assessment of migraine-related cognitive symptoms is recommended.

Cluster

Cluster headaches are strictly unilateral headaches that are far more common in men than in women, but the prevalence in the general population overall is approximately 0.1%. The pain is sharp and steady, in contrast to the throbbing pain of migraine, and localized to the orbital area. Diagnostic criteria require the presence of at least one autonomic sign or symptom during the headache, such as ipsilateral conjunctival injection, lacrimation, rhinorrhea, ptosis, or miosis.

Cluster headache is so called because the headaches occur regularly in most cases, from one to eight times a day, during a period of 2 weeks to 3 months that is referred to as a cluster episode. The headaches then completely remit for months or years. In chronic cluster headache, there are no headache-free periods or remissions, or they are less than 2 weeks in duration. Patients with cluster headache usually describe alcohol intolerance during the cluster episode and generally note intense restlessness during the headache.

Tension Type

Tension-type headaches can vary in length from 30 minutes to 7 days. Diagnostic criteria for tension-type headaches are largely unchanged under ICHD-3. They are typically bilateral, moderate in intensity, and described as a pressing, squeezing sensation that is not affected by physical activity. Associated symptoms, such as nausea, vomiting, photophobia, and phonophobia, are generally not present or are mild. Tension-type headache is subclassified as infrequent episodic if it occurs less than 1 day per month, frequent episodic if it occurs from 1 day to 14 days per month, and chronic with attacks occurring 15 days or more per month for at least 6 months. Patients with tension-type headache typically do not spontaneously report symptoms other than headache. A diagnosis of migraine should be reexamined if multiple associated symptoms are reported, like nausea and photophobia, which are thought to be a part of the sympathetic activation that occurs with migraines.