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For further information, see CMDT Part 2-11: Acute Headache

Key Features

Essentials of Diagnosis

  • Inquire about

    • Age > 40 years

    • Rapid onset with severe intensity; trauma; onset during exertion

    • Fever; vision changes; neck stiffness

    • HIV infection

    • History of hypertension

    • Neurologic findings (mental status changes, motor or sensory deficits, loss of consciousness)

General Considerations

  • In the emergency department, 1% of patients with acute headache have a life-threatening condition

  • In the physician's office, the prevalence of life-threatening conditions is much lower

Clinical Findings

Symptoms and Signs

  • Sudden-onset headache that reaches maximal and severe intensity within seconds or a few minutes ("thunderclap headache") suggests subarachnoid hemorrhage

  • Headache with uncontrolled hypertension should prompt search for other manifestations of "hypertensive urgency or emergency" (See Hypertensive Urgencies & Emergencies)

  • Headache and hypertension in pregnancy may be due to preeclampsia/eclampsia

  • Episodic headache with hypertension, palpitations, and sweats may be due to pheochromocytoma

  • Other historical features that raise the need for diagnostic testing include headache brought on by

    • Valsalva maneuver

    • Cough

    • Exertion

    • Sexual activity

    • Physical examination should include

    • Vital signs

    • Neurologic examination

    • Vision/fundoscopic examination

    • Kernig and Brudzinski signs

  • Patients > 60 years old should be examined for possible scalp or temporal artery tenderness, suggesting temporal arteritis

  • Diminished visual acuity suggests

    • Glaucoma

    • Temporal arteritis

    • Optic neuritis

  • Ophthalmoplegia or visual field defects suggest

    • Venous sinus thrombosis

    • Tumor

    • Aneurysm

  • Afferent pupillary defects occur with intracranial masses or optic neuritis

  • In the setting of headache and hypertension, acute severe hypertensive retinopathy is indicated by

    • Retinal cotton wool spots

    • Flame hemorrhages

    • Disk swelling

  • Ipsilateral ptosis and miosis (Horner syndrome) occur with carotid artery dissection

  • Papilledema or absent retinal venous pulsation or both occur with elevated intracranial pressure

Differential Diagnosis

  • Causes of headache that require immediate treatment

    • Imminent or completed vascular events (intracranial hemorrhage, thrombosis, vasculitis, malignant hypertension, arterial dissection, cerebral venous thrombosis, transient ischemic attack, or aneurysm)

    • Infections (abscess, encephalitis, meningitis)

    • Intracranial masses causing intracranial hypertension

    • Preeclampsia

    • Carbon monoxide poisoning


Laboratory Tests

  • Cerebrospinal fluid (CSF) examination

    • White blood cell count with differential

    • Red blood cell count

    • Glucose

    • Total protein

    • Gram stain

    • Bacterial culture

    • VDRL

  • Erythrocyte sedimentation rate

  • Urinalysis

  • In suspected cases, obtain CSF polymerase chain reaction test for herpes simplex 2

  • In HIV-infected patients, obtain CSF cryptococcal antigen, acid-fast bacillus stain and culture, and complement fixation and culture for coccidioidomycosis

Imaging Studies

  • Sinus CT scan

  • Noncontrast head CT immediately, followed by contrast head CT later

  • In HIV-infected patients, new-onset headache warrants CT with and without contrast or MRI

  • Clinical features associated with acute headache that warrant urgent or emergent neuroimaging are found in Table 2–5

  • Perform neuroimaging prior to lumbar puncture in acute headache with abnormal neurologic ...

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