Subarachnoid Hemorrhage



Subarachnoid Hemorrhage





Acute hemorrhage into space between pia and arachnoid membranes (subarachnoid space). 5% of all strokes; nearly 30,000 cases annually in the United States (annual incidence 1/10,000).

80% due to saccular (“berry”) aneurysms. Other causes listed in Table 46.1. Most common at age 40 to 60; women >men.


Pathology and Epidemiology of Intracranial Aneurysms

Saccular aneurysms: prevalence 2% in adults. Uncommon in children. 20% of patients with subarachnoid hemorrhage (SAH) have two or more aneurysms.



  • Most common sites: junction of posterior communicating and internal carotid arteries (≈ 40%), anterior communicating artery complex (≈ 30%), middle cerebral artery at first major branch point (≈ 20%).


  • Risk of rupture of asymptomatic intracranial aneurysm: 0.7% per year; of previously ruptured aneurysm after 6 months, 2% to 4% per year.


  • Major risk factors for aneurysm: increasing age, atherosclerosis, family history of intracranial aneurysm, autosomal dominant polycystic kidney disease (PCKD). Indications for screening for unruptured aneurysms by MRA: PCKD, 2 or more first-degree relatives with intracranial aneurysms (test positive in 10%).


  • Risk factors for bleeding: previous rupture, large size, cigarette smoking, aneurysm-related headache or cranial nerve compression, alcohol use, family history of SAH, female sex, posterior circulation location, multiple aneurysms, hypertension, cocaine, or amphetamine use.


Clinical Features

Explosive (“thunderclap”) headache, then stiff neck. Often “the worst headache of my life.” Common associated symptoms: loss of consciousness, nausea, vomiting, photophobia, back or leg pain. Focal signs sometimes present.









Table 46.1 Non-Aneurysmal Causes of Subarachnoid Hemorrhage




Trauma
Idiopathic perimesencephalic SAH
Arteriovenous malformation
Intracranial arterial dissection
Cocaine and amphetamine use
Mycotic aneurysm
Pituitary apoplexy
Moyamoya disease
Central nervous system vasculitis
Sickle cell disease
Coagulation disorders
Primary or metastatic neoplasm

Neurologic condition on arrival at hospital most important determinant of outcome (Table 46.2).

Prodromal symptoms (headache, stiff neck, nausea, vomiting, syncope, disturbed vision) in 33%. Prodromal headache may disappear for days before onset of full-blown syndrome (“sentinel headache”).



  • Perimesencephalic SAH: blood confined to perimesencephalic cisterns. Normal neurologic examination; benign course; attributed to venous bleeding.








Table 46.2 Hunt and Hess Grading Scale for Aneurysmal SAH











































    Hospital mortality (%)a
Grade Clinical findings 1968 2002
I Asymptomatic or mild headache 11 7
II Moderate to severe headache, or oculomotor palsy 26 2
III Confused, drowsy, or mild focal signs 37 10
IV Stupor (localizes to pain) 71 35
V Coma (posturing or no motor response to pain) 100 65
TOTAL   35 20
aData from 275 patients reported by Hunt and Hess in 1968, and 404 patients treated at Columbia University Medical Center between 2000 and 2002.

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Jul 27, 2016 | Posted by in NEUROLOGY | Comments Off on Subarachnoid Hemorrhage

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