Convexity subarachnoid haemorrhage

We congratulate Jan Claassen and Soojin Park on their Seminar on spontaneous subarachnoid haemorrhage (SAH);1Claassen J Park S Spontaneous subarachnoid haemorrhage.Lancet. 2022; 400: 846-862Summary Full Text Full Text PDF PubMed Scopus (29) Google Scholar however, we found no mention of non-aneurysmal convexity subarachnoid haemorrhage (cSAH), a SAH subtype associated with a short, but important, list of underlying diagnoses, which require quite different investigation and management. cSAH, limited to the convexities of the brain (figure), accounts for around 6% of all SAH.2Khurram A Kleinig T Leyden J Clinical associations and causes of convexity subarachnoid hemorrhage.Stroke. 2014; 45: 1151-1153Crossref PubMed Scopus (62) Google Scholar In older people (aged >60 years) the most common cause of cSAH is cerebral amyloid angiopathy, usually presenting with transient focal neurological episodes (amyloid spells). Transient focal neurological episodes are usually recurrent, stereotyped attacks of unilateral spreading symptoms including paraesthaesias, numbness, or weakness (alone or in combination), lasting less than 10 min.3Stanton JED Chandratheva A Wilson D Hostettler IC Islam S Werring DJ Clinical features distinguish cerebral amyloid angiopathy-associated convexity subarachnoid haemorrhage from suspected TIA.J Neurol. 2020; 267: 133-137Crossref PubMed Scopus (11) Google Scholar cSAH in cerebral amyloid angiopathy, be it acute or historical (cortical superficial siderosis; figure), is associated with a high risk of further haemorrhage.4Hostettler IC Wilson D Fiebelkorn CA et al.Risk of intracranial haemorrhage and ischaemic stroke after convexity subarachnoid haemorrhage in cerebral amyloid angiopathy: international individual patient data pooled analysis.J Neurol. 2022; 269: 1427-1438Crossref PubMed Scopus (7) Google Scholar In younger people (aged ≤60 years), the most common cause of cSAH is reversible cerebral vasoconstriction syndrome, typically presenting with recurrent thunderclap headaches, with or without focal neurological disturbance due to cerebral ischaemia or haemorrhage.5Ducros A Boukobza M Porcher R Sarov M Valade D Bousser MG The clinical and radiological spectrum of reversible cerebral vasoconstriction syndrome. A prospective series of 67 patients.Brain. 2007; 130: 3091-3101Crossref PubMed Scopus (757) Google Scholar Triggers include pregnancy and sympathomimetic drugs; recovery is usually good, with a low recurrence rate. Other differential diagnoses of cSAH include cerebral venous thrombosis, vascular malformations (eg, dural arteriovenous fistulas or cavernomas), posterior reversible encephalopathy syndrome, and infective endocarditis.6Forman R Conners JJ Song SY et al.The spectrum of nontraumatic convexity subarachnoid hemorrhage.J Stroke Cerebrovasc Dis. 2019; 28104473Summary Full Text Full Text PDF PubMed Scopus (7) Google Scholar For most of these conditions, digital subtraction angiography, an invasive procedure associated with important risks, is unnecessary. We encourage readers to be aware of cSAH and the distinctive clinical features of its main causes. Rapid recognition of cSAH should help minimise unnecessary tests and facilitate accurate prognostication and appropriate treatment. We declare no competing interests. Spontaneous subarachnoid haemorrhageSubarachnoid haemorrhage (SAH) is the third most common subtype of stroke. Incidence has decreased over past decades, possibly in part related to lifestyle changes such as smoking cessation and management of hypertension. Approximately a quarter of patients with SAH die before hospital admission; overall outcomes are improved in those admitted to hospital, but with elevated risk of long-term neuropsychiatric sequelae such as depression. The disease continues to have a major public health impact as the mean age of onset is in the mid-fifties, leading to many years of reduced quality of life. Full-Text PDF