Headaches are a common chief complaint of patients seeking advice from a pharmacist. The three main categories of primary headache disorder are migraine, tension-type, and cluster headaches.
The pathophysiologic and etiologic mechanisms of migraine are not known. The sensory sensitivity may be due to a dysfunction of monoaminergic sensory control systems of the brainstem and thalamus. It is speculated that the trigeminovascular input from the meningeal vessels is a pathway for pain recognized in migraine headaches. There is a release of vasoactive neuropeptides, specifically calcitonin gene-related peptide (CGRP), when the cells in the trigeminal nucleus are activated. There is a deficiency of serotonin levels in the plasma during a migraine attack. The use of serotonin agonists, triptans, in migraine therapy has demonstrated the role of serotonin in treatment, being potent agonists of 5-HT1B, 5-HT1D, and 5-HT1F. Dopamine may also play a role in migraine headaches as dopamine receptor antagonists are effective treatments administered as monotherapy or with other antimigraine medications; however, there is a lack of clinical data to support this theory.
The pathophysiology behind tension headache also remains unknown, but one hypothesis is that stress is an important stimulus. Cluster headaches may be precipitated by hypothalamic-related changes in cortisol, prolactin, testosterone, growth hormone, luteinizing hormone, endorphins, or melatonin.
When considering the diagnosis of headaches, a comprehensive history of present illness and physical examination are critical. A thorough history will include time of onset, attack frequency, duration, aggravating and relieving factors, characteristics of pain, associated signs and symptoms, and treatment history. History and physical examination findings that may be suggestive of a secondary headache disorder include the worst headache ever, head pain with exercise, sneezing or coughing, headache that wakes patient from sleep, ataxia, history of head trauma, and changes in mental status. Headaches beginning after the age of 50 suggest underlying issues such as a mass lesion or cerebrovascular disease. Any of these findings are considered red flags that warrant a referral to the physician.
The types of headaches are differentiated based upon duration, location, frequency, severity, and quality of pain. Tension headaches last 30 minutes to 7 days and are located in the occipital or frontal region of the head with a band-like tightness. Pain associated with cluster headaches is unilateral and the headaches are vascular in nature, producing pain around the eye, temple, or forehead. Cluster headaches resolve within 3 hours and are accompanied with nasal congestion, watering eyes, eyelid edema, or ptosis. There is clinical variability among migraine headaches. Onset of migraine pain is gradual with the peak occurring in minutes to hours. In adults, pain lasts 4 to 72 hours and located in the frontal or temporal region of the head. Patients describe the headache as moderate to severe, pulsating, and aggravated by physical activity. A combination of nausea, vomiting, photophobia, and phonophobia accompany the headache. Migraine headaches ...