Headache, Acute

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 clinician's office, the prevalence of life-threatening conditions is much lower

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

• 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

• A systematic list called the SNNOOP10 has been developed as a screen for secondary causes of headache (Table 2–7)

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 examination, abnormal mental status, abnormal fundoscopic examination (papilledema; loss of venous pulsations)

• Perform neuroimaging emergently in acute headache with abnormal neurologic examination, abnormal mental status, "thunderclap headache"

• Perform neuroimaging urgently in acute headache with HIV infection, age > 50 years (despite normal neurologic examination)

• Optic nerve ultrasonography (optic nerve sheath diameter sonography) has been proposed as a noninvasive, quick method for diagnosing increased intracranial pressure (Table 2–7)

Diagnostic Procedures

• If high suspicion for subarachnoid hemorrhage or aneurysm, lumbar puncture followed by cerebral angiography

• Lumbar puncture may be withheld if

  • CT scan is performed < 6 hours after headache onset

  • Scan did not show subarachnoid hemorrhage (negative predictive value 99.9% [95% CI, 99.3–100.0%])

• Treatment should be guided by the underlying etiology

• High flow oxygen therapy may be effective in cluster, migraine, tension, and undifferentiated headache

Medications

• Nonsteroidal anti-inflammatory drugs (Table 5–5)

• Migraine therapy (Table 24–1)

• Opioid analgesics (Table 5–6)

• Clinical response to analgesics does not exclude life-threatening causes of acute headache

Therapeutic Procedures

• For treatment-refractory migraine in pregnant women, peripheral nerve blocks of greater occipital, auriculotemporal, supraorbital, and supratrochlear nerves may be effective

• Surgical decompression of peripheral, cranial and spinal nerves at trigger sites have been used to treat migraine

Prevention

• Prophylactic treatment of migraine (Table 24–1)

When to Refer

• Frequent migraines not responsive to standard therapy

• Migraines with atypical features

• Chronic daily headaches due to medication overuse

When to Admit

• Need for repeated doses of parenteral pain medication

• To facilitate an expedited work-up requiring a sequence of neuroimaging and procedures

• To monitor for progression of symptoms and to obtain neurologic consultation when the initial emergency department work-up is inconclusive

• Pain severe enough to impair activities of daily living or limit participation in follow-up appointments or consultations

• Patients with subarachnoid hemorrhage, intracranial mass, or meningitis