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A. Symptoms and Signs
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The majority of patients presenting with headache have a normal neurologic and general physical examination; for this reason, the headache history is of utmost importance (Table 29-1). A key issue in the headache history is identifying patients presenting with “red flags”—diagnostic alarms that prompt greater concern for the presence of a secondary headache disorder and a greater potential need for additional laboratory evaluation and neuroimaging (Table 29-2).
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The onset of primary headache disorders is usually between 20 and 40 years of age; however, they may occur at any age. Patients without a history of headaches who present with a new-onset headache outside this age range should be considered at higher risk for a secondary headache disorder. Additional testing or neuroimaging in these patients or those complaining of their “first or worst” headache should be seriously considered. Temporal (giant cell) arteritis should be a consideration in any patient aged ≥50 years with a new complaint of head, facial, or scalp pain, diplopia, or jaw claudication.
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Symptoms suggesting a recurring, transient neurologic event, typically lasting 30–60 minutes and preceding headache onset, strongly suggest the presence of an aura and an associated migraine headache disorder. Migraine without aura, the most common form of migraine (formerly called common migraine), may present with unilateral pain in the head (cephalalgia) with subsequent generalization of pain to the entire head. Bilateral cephalalgia is present in a small percentage of migraineurs at the onset of their headache. Nausea accompanying a migraine may be debilitating and warrant specific treatment. After excluding secondary headache disorders, the combination of disability, nausea, and sensitivity to light has a positive predictive value of 0.93 for migraine headache among primary care patients.
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Cluster headaches are strictly unilateral in location and are typically described as an explosive, deep, excruciating pain. They are associated with ipsilateral autonomic signs and symptoms, and have a much greater prevalence in men.
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Tension-type headaches, the most prevalent form of primary headache disorder, often present with pericranial muscle tenderness and a description of a bilateral bandlike distribution of the pain.
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Patients with chronic medical conditions have a greater possibility of having an organic cause of their headache (see Table 29-2). Patients with cancer, hypertension (with diastolic pressures >110 mmHg), or human immunodeficiency virus (HIV) infection may present with central nervous system (CNS) metastases, lymphoma, toxoplasmosis, or meningitis as the etiology of their headache. Numerous medications have headache as a reported adverse effect, and medication overuse headache (formerly drug-induced headache) may occur following frequent use of analgesics or any antiheadache medication, including the triptans (eg, sumatriptan). The duration and severity of withdrawal headache following discontinuation of the medication varies with the medication itself; withdrawal is shortest for triptans (4.1 days) compared with ergots (6.7 days) or analgesics (9.5 days), respectively. Medical or dental procedures (lumbar punctures, rhinoscopy, tooth extraction, etc) may be associated with postprocedure headaches. Any history of head trauma or loss of consciousness should prompt concern for an intracranial hemorrhage in addition to a postconcussive disorder.
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2. Physical examination
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Physical examination is performed to attempt to identify a secondary, organic cause for the patient’s headache. Additionally, any red flags identified during the headache history (see Table 29-2) warrant special attention. A general physical examination should be performed, including vital signs; general appearance; and examinations of the head, eyes (including a funduscopic examination), ears, nose, throat, teeth, neck, and cardiovascular regions. Palpation of the head, face, and neck should also be a priority.
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A detailed neurologic examination should be performed and the findings well documented. Assessment includes mental status testing; level of consciousness; pupillary responses; gait; coordination and cerebellar function; motor strength; sensory, deep tendon, and pathologic reflex testing; and cranial nerve tests. The presence or absence of meningeal irritation should be sought. Examinations such as evaluation for Kernig and Brudzinski signs should be documented; both signs may be absent, however, even in the presence of subarachnoid hemorrhage.
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B. Laboratory Findings and Imaging Studies
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Additional laboratory investigations should be driven by the history and any red flags that have been identified (see Table 29-2). The routine use of electroencephalography is not warranted in the evaluation of the patient with headache. Although various characteristics may lead to selection of either computed tomography (CT) or magnetic resonance imaging (MRI) (Table 29-3), routine use of neuroimaging is not cost-effective.
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The US Headache Consortium has provided evidence-based guidelines on neuroimaging in the patient with nonacute headache. They revealed the prevalence of patients with a normal neurologic examination, and migraine having a significant abnormality (acute cerebral infarct, neoplastic disease, hydrocephalus, or vascular abnormalities, eg, aneurysm or arteriovenous malformation) on a neuroimaging test is 0.2%. Their recommendations are as follows:
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Neuroimaging should be considered in patients with nonacute headache and an unexplained abnormal finding on neurologic examination.
Evidence is insufficient to make specific recommendations in the presence or absence of neurologic symptoms.
Neuroimaging is seldom warranted for patients with migraine and normal neurologic examination. For patients with atypical headache features or patients who do not fulfill the strict definition of migraine (or have some additional risk factor), a lower threshold for neuroimaging may be applied.
Data were insufficient to yield an evidence-based recommendation regarding the use of neuroimaging for tension-type headache.
Data were insufficient to yield any evidence-based recommendations regarding the relative sensitivity of MRI compared with CT in the evaluation of migraine or other nonacute headache.
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Although the US Headache Consortium based the preceding recommendations on a review of the best available evidence, clinicians must individualize management plans to meet a variety of needs, including addressing patient fears and medicolegal concerns.
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Within the first 48 hours of acute headache, CT scanning without contrast medium followed, if negative, by lumbar puncture and cerebrospinal fluid (CSF) analysis, is the preferred approach to attempt to diagnose subarachnoid hemorrhage. Xanthochromia, a yellow discoloration detectable on spectrophotometry, may aid in diagnosis if the CT scan and CSF analysis are normal yet if suspicion of subarachnoid hemorrhage remains high. Xanthochromia may persist for ≤1 week following a subarachnoid hemorrhage.
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In addition to CSF analysis, lumbar puncture is useful for documenting abnormalities of CSF pressure in the setting of headache. Headaches are associated with low CSF pressure (<90 mm H2O as measured by a manometer) and elevated CSF pressure (>200–250 mm H2O). Headaches related to CSF hypotension include those caused by posttraumatic leakage of CSF (ie, after lumbar puncture or CNS trauma). Headaches related to CSF hypertension include those associated with idiopathic intracranial hypertension and CNS space–occupying lesions (ie, tumor, infectious, mass, hemorrhage).
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