Familial perimesencephalic subarachnoid hemorrhage: two case reports

Area of Science:

• Neurology
• Neurosurgery
• Genetics

Background:

• Perimesencephalic non-aneurysmal subarachnoid hemorrhage (PNSAH) is a specific type of spontaneous subarachnoid hemorrhage, typically localized around the midbrain.
• PNSAH accounts for approximately 5% of all spontaneous subarachnoid hemorrhage cases.
• The underlying mechanisms of PNSAH are not fully understood, though familial predisposition is increasingly recognized.

Observation:

• The study presents two unrelated Caucasian male siblings diagnosed with PNSAH.
• The first patient, aged 39, presented with sudden headache and diplopia, confirmed by CT scan as PNSAH with no aneurysm found on angiography.
• His 44-year-old brother presented 1.5 years later with similar symptoms and CT findings of PNSAH, also without an identifiable bleeding source on angiography.

Findings:

• Both siblings experienced typical PNSAH symptoms and imaging findings.
• Angiographic evaluations in both cases failed to identify any vascular source for the hemorrhage.
• The occurrence of PNSAH in two siblings strongly supports a potential genetic or familial component.

Implications:

• The findings suggest a possible familial predisposition for PNSAH.
• First-degree relatives of individuals diagnosed with PNSAH may face an elevated risk.
• Further research into the genetic factors contributing to PNSAH is warranted.