Non-aneurysmal perimesencephalic subarachnoid hemorrhage in a pediatric patient: case report

*Correspondence: [e-mail].

Abstract

Case Presentation: Male, 6-years-old, previously healthy, with no recent history of head trauma, presented with acute intense headache in the occipital area while doing physical activity, associated with vomit and back pain. He was medicated for pain at home and evolved with partial improvement of the symptoms. 10 hours later, he had a new episode of headache with the same characteristics, this time waking him up at night. In the emergency room, he presented with cervical hyperextension and nuchal rigidity. Lumbar puncture came back with numerous erythrocytes and computed tomography of the head showed subarachnoid hemorrhage in the prebulbar, prepontine and interpeduncular areas, and in the supraselar cystern, with blood in the fourth ventricle. The patient was then transferred to the Intensive Care Unit and further investigated with an arterial angiotomography of the head, that didn’t show any additional alterations. The neurosurgery team suggested conservative care, and child neurology was then consulted. Nimodipine 0,5mg/kg every 4 hours was initiated to prevent vasoespasm. He evolved with progressive improvement of the symptoms and after a week of the initial event a magnetic ressonance was performed, that showed regression of the hemorrhage. Laboratory results, including coagulation tests, came back normal. Due to the benign evolution of this case, non-aneurysmal perimesencephalic subarahacnoid hemorrhage (PMSAH) was suspected, and venous angioressonance confirmed the presence of a primitive variant of the basal vein of Rosenthal draining into the left transverse sinus, which is commonly seen in this diagnosis. Since the risk of vasoespasm reduces drastically after a week of the event and is close to zero after 15 days, nimodipine was discontinued and the patient was discharged after 17 days of the event, completely asymptomatic.

Discussion: PMSAH is a rare condition in adults and has not been previously described in pediatric patients. The treatment of this patient was, therefore, conducted according to adult guidelines. Still, the prognosis is usually excellent, with full recuperation in most cases and extremely low chances of reoccurrence. Once the presence of a primitive variant of the basal vein of Rosenthal is confirmed, no further and more invasive exams are needed.

Final Comments: PMSAH should be remembered as an uncommon presentation of subarachnoid hemorrhage, but other etiologies of hemorrhagic stroke must always be investigated.

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Artikel online veröffentlicht:
12. Mai 2025