Summary
Definition
History and exam
Key diagnostic factors
- headache
- photophobia
- loss of consciousness
- third cranial nerve palsy
Other diagnostic factors
- age >50 years
- female sex
- black people
- nausea/vomiting
- altered mental status
- meningismus
- unilateral or bilateral sixth cranial nerve palsies
- intraocular hemorrhage
- focal neurologic deficits
Risk factors
- hypertension
- smoking
- family history
- autosomal dominant polycystic kidney disease (ADPKD)
- alcohol use
- cocaine use
- Marfan syndrome
- Ehlers-Danlos syndrome
- pseudoxanthoma elasticum
- neurofibromatosis type I
Diagnostic investigations
1st investigations to order
- CT head
- CBC
- clotting profile
- serum electrolytes
- troponin I
- ECG
Investigations to consider
- lumbar puncture (LP)
- digital subtraction angiography (DSA)
- computed tomography angiography (CTA)
- magnetic resonance angiography (MRA)
Treatment algorithm
all patients
Contributors
Authors
Salah Keyrouz, MD, FAHA
Associate Professor
Neurology and Neurosurgery
Washington University School of Medicine
St. Louis
MO
Disclosures
SK is an author of a reference cited in this topic.
Acknowledgements
Dr Salah Keyrouz would like to gratefully acknowledge Dr Michael N. Diringer, a previous contributor to this topic.
Disclosures
MND is an author of a number of references cited in this topic.
Peer reviewers
Venkatesh Aiyagari, MD
Associate Professor
Department of Neurology and Rehabilitation
University of Illinois at Chicago
Chicago
IL
Disclosures
VA declares that he has no competing interests.
Peter Martin, MA, BM BCh, MD, FRCP
Consultant Neurologist
Addenbrookes Hospital
Cambridge
UK
Disclosures
PM declares that he has no competing interests.
Giovanni Grasso, M.D., PhD
Aggregate Professor of Neurosurgery
Neurosurgical Clinic
Department of Clinical Neuroscience
University of Palermo
Palermo
Italy
Disclosures
GG declares that he has no competing interests.
Differentials
- Nonaneurysmal perimesencephalic SAH
- Arterial dissection
- Cerebral and cervical arteriovenous malformation (AVM)
More DifferentialsGuidelines
- ACR Appropriateness Criteria®: headache
- ACR Appropriateness Criteria®: cerebrovascular diseases - aneurysm, vascular malformation, and subarachnoid hemorrhage
More GuidelinesPatient leaflets
Subarachnoid haemorrhage
More Patient leafletsVideos
Diagnostic lumbar puncture in adults: animated demonstration
Tracheal intubation: animated demonstration
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