Characteristic features and initial diagnostic imaging for common underlying causes of spontaneous isolated convexity subarachnoid hemorrhage

Characteristic feature(s)	Suspected etiology	Choice of initial diagnostic imaging test(s)
Age >60 years Baseline cognitive impairment	CAA	MRI brain with T2*-weighted SWI or GRE sequences
Recurrent thunderclap headache (>2 within 1 week) Exposure to vasoactive substance	RCVS	CTA or MRA of head MRI brain
Risk factor for venous thrombosis* Head CT features suggestive of venous thrombosis (eg, hyperdense venous sinus; venous infarction)	CVT	CTV or MRV of head MRI brain
New heart murmur Systemic/cutaneous evidence of embolism	Mycotic aneurysm	MRI brain with contrast or cerebral DSA
Clinical history of active cancer Clinical history of new persistent headaches Head CT features suggestive of tumor (eg, vasogenic edema)	Brain tumor	MRI brain with contrast
Headache prior to neurologic deficits Clinical history of connective tissue disorder	Intracranial dissection	CTA of head or cerebral DSA
Head CT features suggestive of AVM (calcification or hypodense flow voids adjacent to SAH)	AVM	Cerebral DSA
History of minor/occult trauma may be elicited Evidence of extracranial bleeding or systemic injuries	Occult trauma	MRI brain
Clinical history of new persistent headaches Progressive cognitive or other neurologic impairments	Vasculitis	MRI brain with contrast Cerebral DSA Brain and meningeal biopsy

Patients with spontaneous isolated convexity SAH present with bleeding restricted to the surface of the cerebral hemispheres. The suspected underlying cause of convexity SAH may be identified by initial diagnostic imaging test. Additional imaging and/or other testing may be warranted if initial imaging is nondiagnostic. Refer to specific UpToDate topics for additional information on the diagnostic evaluation of conditions that may present with convexity SAH.

SAH: subarachnoid hemorrhage; CAA: cerebral amyloid angiopathy; MRI: magnetic resonance imaging; SWI: susceptibility-weighted imaging; GRE: gradient recall echo imaging; RCVS: reversible cerebral vasoconstriction syndrome; CTA: computed tomographic angiography; MRA: magnetic resonance angiography; CT: computed tomography; CVT: cerebral venous thrombosis; CTV: computed tomography venography; MRV: magnetic resonance venography; DSA: digital subtraction angiography; AVM: arteriovenous malformation.

* Refer to UpToDate topic on the causes of venous thrombosis.

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خرید پکیج

Characteristic features and initial diagnostic imaging for common underlying causes of spontaneous isolated convexity subarachnoid hemorrhage