
Heena Dobhal
Shri Guru Ram Rai Institute of Medical & Health Sciences, IndiaPresentation Title:
A case of quadrigeminal variant of perimesencephalic nonaneurysmal subarachnoid hemorrhage
Abstract
Background: Nonaneurysmal Perimesencephalic Subarachnoid Hemorrhage (PMSAH) appears to have an etiology and natural history distinct from aneurysm rupture. Referral-based studies suggest that 15% of SAH patients have no discernable cause of bleeding, but the incidence of PMSAH is unknown. Perimesencephalic Non-Aneurysmal Subarachnoid Haemorrhage (PMNASAH) can be a diagnostic challenge, especially in an alert, neurologically intact patients. The most widely accepted definition emphasizes the presence of blood ventral to the midbrain or pons on early computed tomography. Quadrigeminal SAH is a variant of PNSH that is not well described in the literature. It may comprise up to one-fifth of PNSH cases and carries a similar benign prognosis. This variant of Perimesencephalic Subarachnoid Hemorrhage (PSAH) is characterized by blood centered in the quadrigeminal cistern and limited to the superior vermian and perimesencephalic cisterns. Non-contrast CT of the brain is the initial investigation of choice while angiogram is the gold standard for the diagnosis of SAH. We report a case at our institute.
Methods: A 29 year old female presented to emergency with history of severe sudden onset headache and fall followed by drowsiness at home. She was not able to recall incidents post-fall. She had no focal neurological deficits or meningeal signs on examination. Her fundoscopy was normal. Routine bloods including full blood count, renal profile, coagulation screening and cardiac enzymes were unremarkable. Her baseline chest X-ray and ECG were also normal. CT Scan done was suggestive of subarachnoid hemorrhage is seen perimesencephalic spacequadrigeminal cistern. 4-vessel cerebral DSA was suggestive of no intracranial aneurysm. Diagnosis of Perimesencephalic Non-Aneurysmal Subarachnoid Haemorrhage (PMNASAH) was established based on the radiological features. She received prophylactic Nimodipine and made a good recovery prior to being discharged home.
Results: The patient presented with non-aneurysmal perimesencephalic variant of sub-arachnoid hemorrhage. She was managed conservatively and Nimodipine given. The patient responded well to treatment and was discharged home, with advise of follow-up for check DSA after 6 weeks.
Conclusions: PMSAH represents approximately 5% of all SAH. A small subset of patients with nonaneurysmal PSAH present with blood centered in the quadrigeminal cistern, and the etiology of this pattern may be similar to that of the classic pretruncal variant. However, patients with quadrigeminal PSAH must still undergo thorough vascular imaging, including at least two digital subtraction angiograms, to exclude a ruptured aneurysm. Diagnostic cerebral angiography is gold standard as aneurysm rupture may produce similar pattern of bleeding. In majority of cases, the aetiology remains unknown and there are no specific treatments for PMNASAH. Prompt diagnosis and early recognition of PMNASAH is prudent as it carries an excellent long-term prognosis with good clinical outcomes compared with aneurysmal SAH.
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