Headache is a common presentation to the emergency department, and the diagnosis is often relatively straightforward. It's not that difficult to make a diagnosis of headache caused by meningitis, intracranial hemorrhage, or brain tumor—tests can readily substantiate these diagnoses.
Most causes of headache are benign and only vaguely understood or accurately diagnosed in the ED. Many patients are treated and released without a definitive diagnosis because clinicians usually label them tension headaches or sinusitis. Migraine headaches are actually quite common and the leading cause of time spent disabled. Migraines are often relatively classic in their presentation, and can usually be handled with simple attempts at pain relief, but the first-time migraine headache is a challenge to emergency physicians. Migraines also have multiple treatment regimens, many with reasonable results, though the specific treatment is often based on the preference of the individual provider. The most specific way to confirm the diagnosis of migraine headache includes a careful history and exam, clinical gestalt, and a few simple tests.
New Engl J Med
This good review of migraine headaches looks at the clinical problems involved in diagnosing and evaluating specific treatments. The article begins with a case history, and then discusses how this patient would be evaluated and treated. The scenario is apparently in an office setting, but the same principles apply to the ED.
The author noted that migraine headache is a major public health issue, one that can begin in childhood. It increases during the teenage years, but gradually decreases around 40, particularly among women after menopause. Migraine is more common in women than men, and the presentations can be broad in frequency and severity. Migraines are relatively easy to handle once diagnosed, but some patients frequently have incapacitating symptoms refractory to most therapies. This author quoted an amazing statistic: As many as one in 25 women has a chronic migraine history with symptoms more than 15 days per month.
A typical migraine headache has premonitory symptoms that may occur minutes to hours before the actual headache begins and postdromal symptoms that can persist for hours after the headache ends. Common symptoms prior to headache include yawning, mood changes, light or sound sensitivity, neck pain, or fatigue, and many of these will persist after the headache recedes. Other common premonitory symptoms include visual hallucinations, such as wavy lines, dark or bright spots, diffuse numbness and tingling, language dysfunction, and vertigo. Often these initial symptoms are only reported to the physician when the patient is specifically questioned about them.
The diverse and variable symptoms of the migraine complex involve multiple alterations in the function of the central nervous system. The pathophysiology is partly known, but is inscrutable to mere clinicians. Multiple brain regions are affected, including the hypothalamus, thalamus, brainstem, and cortex. It was previously considered that a migraine was primarily a vascular disorder, with the headache caused by constriction and dilation of cerebral blood vessels. This concept has largely been refuted. It is now clear that constriction of blood vessels is not a required mechanism and not involved in therapy for migraines, but the underlying mechanism of migraine remains uncertain. This author believes that migraine is underdiagnosed. Recurrent headaches associated with any sensitivity to light, nausea, or reduced ability to function is likely a migraine, regardless of the other characteristics. The inability to function normally may be more useful in diagnosis than the varying characteristics of the headache.
Other common migraine symptoms, such as cognitive dysfunction, dizziness, fatigue, and a variety of neurological symptoms often precipitate a head CT scan as part of the diagnostic workup. The neck pain in migraines is often misinterpreted as disorders of the cervical spine. Many people (as well as clinicians) think the pain is a sinus headache. For the majority of migraine patients who are not initially thought to have migraine, sinusitis is the incorrect diagnosis given. A variety of lifestyle modifications have been linked to migraine, such as skipped meals, caffeine, irregular sleep, stress, and menstruation. The relationship of these factors to migraine is unclear. Multiple medications can cause migraines, including oral contraceptives, post-menopausal hormone therapy, nasal decongestants, SSRIs, antidepressants, and proton pump inhibitors. Adjusting or discontinuing these medications is the only way to prove them causal.
Comment: Migraine is an episodic disorder. Characteristic is a mild to severe debilitating headache that is generally associated with nausea or light or sound sensitivity. It is one of the most common complaints encountered by neurologists, but patients with migraine often end up in the ED, particularly for their first episode. The actual cause of migraine is still under investigation, but the once-popular theory of migraine consisting of cerebral vascular vasoconstriction and vasodilation is no longer considered viable.
Migraines have four phases: premonitory, aura, headache, and postdromal. One presumed mechanism for migraine is the concept of cortical spreading depression. This is a self-propagating wake of neuronal depolarization that spreads across the cerebral cortex, causing the aura of migraine and eventually the headache. Inflammatory changes in pain-sensitive meninges are thought to generate the headache through complex central and peripheral reflex mechanisms, which are largely unknown.
The underlying pathophysiology of migraine includes activation of the trigeminal vascular system, which consists of small-caliber sensory neurons. These sensory neurons innervate large vessels, PIA vessels, dura mater, and large venous sinuses. Migraine includes a complex mechanism of neurological dysfunction, and the role of serotonin receptor activation is unknown. Migraine is often inherited, though a true genetic basis for migraine has not been clarified.
Migraine may present in childhood, but most patients are 20-30, with a prevalence in women. It would be unusual for migraine to be considered as a diagnosis for the first headache in those aged 50-60. Migraines, in fact, generally defervesce at these ages.
Many migraineurs often have 12-48 hours of vague prodromal symptoms, such as increased yawning, euphoria, depression, irritability, food cravings, or constipation, and they may not be appreciated in the patient's first history. About 25 percent of those with migraines have an aura where they have at least one focal neurological symptom, such as bright lines, sharp shapes or objects in the vision, auditory hallucinations, a variety of burning pains and paresthesias, or even some repetitive jerking movements. Visual auras are varied, often including zigzag lines or other visual abnormalities that are difficult to describe.
An initial migraine in an individual with a severe headache and neurological symptoms often suggests stroke in the ED. Sensory symptoms such as a tingling or numbing sensation across one side of the face or down a limb can also occur, and support consideration for ischemic stroke. Dysphasia or changes in language are also occasionally seen, including mumbling of words or frank dysphasia. These are often considered hemiplegic migraines, and the aura often takes the form of motor weakness, while the acute phase follows with headache, visual changes, numbness, paresthesia, aphasia, lethargy, and sometimes even coma. Most clinicians would first consider stroke in such a patient.
The headache associated with migraine is often but not always unilateral, and tends to have a throbbing or pulsatile nature, especially at its maximum. This does not actually correspond to the pulse. The pain can increase over a number of hours, and the patient frequently experiences nausea and sometimes vomiting. Symptoms tend to resolve with sleep, but migraine can last from four hours to several days. After the headache, patients often feel drained or exhausted, or sometimes they feel mild elation or euphoria.
No laboratory tests can point to a diagnosis of migraine. The big question in the ED is whether to obtain neuroimaging, specifically a head CT scan with and without contrast. MRIs are also considered. Clinical situations that often warrant CNS imaging are found in the table.
Diagnosing migraine in the ED is easiest when the patient has a history of migraines and tells you he is having another. Occasionally, however, prolonged migraines can result in ischemia or intracerebral hemorrhage (termed migrainous infarction), so one cannot be totally clinical in the diagnosis. It seems reasonable to perform a head CT scan in patients having their first migraine, one lasting longer than 72 hours, or one that is extremely unusual. The co-existence of the neurological findings often makes it difficult to differentiate between cerebral events and migraine, so many patients will have multiple CT scans, particularly if they go to different care providers.
The differential diagnosis for migraines includes transient ischemic attacks. Often they can be distinguished by the nature of the symptoms, progression, duration, timing associated with the attack, or the presence of non-focal symptoms. Unfortunately, TIA and migraine symptoms are all fully reversible, and neuroimaging is unrevealing. An ischemic event is more likely if the symptoms have sudden onset rather than a gradual progression and lack a significant prodrome or aura. Ischemic events are also less likely to have visual findings and nausea, vomiting, photophobia, or sensitivity to sound. Although rare, cerebral artery dissection can mimic a migraine.
Some clinicians await the result of treatment as a way to diagnose migraines, although the response to medications is not an appropriate way to confirm a diagnosis. Treatment with typical migraine medications resulting in a patient getting back to normal is reassuring, however. Fortunately, many migraines are diagnosed in a neurologist's office, and the ED is just the place for treating those who have failed preventive therapies.
Next month: Treating migraines.
Scenarios that Warrant Neuroimaging
- Suspicion for subarachnoid hemorrhage or cerebral artery dissection. Generally CT scan with and without contrast. MRI is an alternative. Angiography is used for suspected cerebral artery dissection.
- The first bad or worst headache ever
- Headache lasting longer than 72 hours
- Recent significant change from the prior pattern, frequency, or severity, such as sudden onset
- Unexplained neurologic signs or symptoms
- Headache always on the same side
- Headaches not responding to standard or previously effective treatment
- New-onset headache after age 50
- New-onset headaches in patients with cancer or HIV infection
- Associated symptoms and signs such as fever, stiff neck papilledema, cognitive impairment, or personality change
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