Perimesencephalic subarachnoid hemorrhage

Case contributed by Dr Hoe Han Guan

Presentation

Alleged fall due to dizziness. Sustained left periorbital hematoma.

Patient Data

Age: 80 years
Gender: Male

Acute subarachnoid hemorrhage around the midbrain and basal cisterns, namely bilateral ambient cisterns, left crural cistern, quadrigeminal cistern and left suprasellar cistern. There is extension into the left foramen of Luschka, forth ventricle and as well as hyperdense layerings in occipital horn of bilateral lateral ventricles.
The acute SAH is much thicker at the left ambient cistern, measuring up to 1.2cm in thickness. 

Basal cisterns are partially effaced.

Left periorbital hematoma with extension to the left maxilla inferiorly. Both eye globes are normal in configuration. 

Anterior circulation:
Visualized internal carotid arteries, both middle cerebral arteries and both anterior cerebral arteries are well opacified and normal in caliber.
Anterior communicating artery and left posterior communicating artery present. Right PCOM artery is not visualized.

Posterior circulation:
Dominant left vertebral artery.
Both visualized vertebral arteries, basilar artery, both superior cerebellar arteries and both posterior cerebral arteries are well opacified and normal in caliber.

No obvious stenosis, aneurysm , arteriovenous malformation or AV fistula.

Case Discussion

Patient has background medical illness of atrial fibrillation and was on long term anticoagulant. The usage of anticoagulant has increased this patient's bleeding risk with trivial trauma. The anticoagulant was withhold and the patient was treated conservatively.

95% of cases of perimesencephalic subarachnoid hemorrhage have a normal cerebral angiogram.

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