perimesencephalic_subarachnoid_hemorrhage_diagnosis

Perimesencephalic subarachnoid hemorrhage diagnosis

PMSAH has been defined as subarachnoid haemorrhage, which on CT within three days of symptom onset:

It is centred anteriorly to the pons and midbrain

May extend into the basal and suprasellar cisterns and into the proximal/basal Sylvian and interhemispheric fissures may settle as sediment in the occipital horns of the lateral ventricles but there is no overt intraventricular haemorrhage

Is recommended for PMSAH to investigate for possible aneurysmal cause.

Undertaking a DSA after a negative CTA may not add any further diagnostic value in patients with PMSAH and may lead to net harm. This observation needs to be validated in a large-scale prospective multicenter study with complete case ascertainment and robust data on CTA and DSA complications 1)

95% of cases have a normal cerebral angiography and the source of bleeding is not identified; the cause is thought to be a venous bleed. The other 5% of cases are due to a vertebrobasilar aneurysm and the prognosis is worse.

Undertaking a DSA after a negative CTA may not add any further diagnostic value in patients with PMSAH and may lead to net harm. This observation needs to be validated in a large-scale prospective multicenter study with complete case ascertainment and robust data on CTA and DSA complications 2).


A repeat DSA is definitely not required in PM-SAH, but it should be done for all cases of nPM-SAH, before labeling them as nonaneurysmal SAH 3).


1) , 2)
Mohan M, Islim A, Dulhanty L, Parry-Jones A, Patel H. CT angiogram negative perimesencephalic subarachnoid hemorrhage: is a subsequent DSA necessary? A systematic review. J Neurointerv Surg. 2019 Dec;11(12):1216-1221. doi: 10.1136/neurintsurg-2019-015051. Epub 2019 Jul 4. PMID: 31273072.
3)
Yeole U, Nagesh M, Shukla D, R AH, R PA. The Yield of Repeat Angiography in Angiography-Negative Spontaneous Subarachnoid Hemorrhage. J Neurosci Rural Pract. 2020 Oct;11(4):565-572. doi: 10.1055/s-0040-1714313. Epub 2020 Aug 11. PMID: 33144792; PMCID: PMC7595787.
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  • Last modified: 2021/04/27 13:48
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