Subarachnoid Hemorrhage, Spontaneous

Key Features

Essentials of Diagnosis

• Sudden ("thunderclap") severe headache

• Signs of meningeal irritation usually present

• Obtundation is common

• Focal deficits frequently absent

General Considerations

• 5–10% of strokes are due to subarachnoid hemorrhage

• Trauma is the most common cause

• Frequently results from the rupture of an arterial saccular ("berry") aneurysm or from an arteriovenous malformation

• Factors associated with a higher risk of subarachnoid hemorrhage

  • Older age

  • Female sex

  • "Non-white" ethnicity

  • Hypertension

  • Tobacco smoking

  • High alcohol consumption (exceeding 150 g per week)

  • Previous symptoms

  • Posterior circulation aneurysms

  • Larger aneurysms

• See also Aneurysm, Intracranial

• See Table 24–3

Clinical Findings

Symptoms and Signs

• Sudden onset of headache with severity never experienced previously by the patient

• May be followed by nausea and vomiting and loss or impairment of consciousness (transient, or progressing to coma and death)

• Patient is often confused and irritable and may show other symptoms of an altered mental status

• Nuchal rigidity and other signs of meningeal irritation are seen, except in deeply comatose patients

• Focal neurologic deficits may be present and may suggest the site of the underlying lesion

• See also Aneurysm, Intracranial

Differential Diagnosis

• Meningitis

• Migraine

• Intracerebral hemorrhage

• Ischemic stroke

Diagnosis

Laboratory Findings

• Cerebrospinal fluid demonstrates an elevated red blood cell count

• Peripheral leukocytosis

• Transient glycosuria

Imaging Studies

• CT scan (preferably with CT angiography) should be performed immediately to confirm that hemorrhage has occurred and to search for its source

• CT is faster and more sensitive in detecting hemorrhage in the first 24 hours than MRI

• Rarely, CT is normal in patients with suspected hemorrhage

• If CT is normal in such patients, examine cerebrospinal fluid for blood or xanthochromia before the possibility of subarachnoid hemorrhage is discounted

Diagnostic Procedures

• Electrocardiographic evidence of arrhythmias or myocardial ischemia has been well described and probably relates to excessive sympathetic activity

• Cerebral arteriography helps determine the source of bleeding

• Bilateral carotid and vertebral arteriography are necessary because aneurysms are often multiple, while arteriovenous malformations may be supplied from several sources

• CT angiography or MR angiography may also be revealing but is less sensitive than conventional arteriography

Treatment

Medications

• Phenytoin to prevent seizures; however, evidence of benefit is conflicting

Surgery

• Surgical clipping of aneurysm base or endovascular treatment by coil embolization is definitive treatment, ideally performed within 2 days of the hemorrhage

Therapeutic Procedures

• Major aim is to prevent further hemorrhage

• Conscious patients

  • Confine to ...