The clinical course of perimesencephalic nonaneurysmal subarachnoid hemorrhage

Abstract

We studied the early clinical course of 65 patients with perimesencephalic (nonaneurysmal) subarachnoid hemorrhage. None of the patients rebled; none had delayed cerebral ischemia; and only 3 patients (5%) developed clinical signs of acute hydrocephalus, 2 requiring ventricular shunting. Hyponatremia and electrocardiographic changes were found in the same proportions as in patients with aneurysmal rupture. All patients had a good outcome after 3 months. To control for the influence of the relatively small amount of cisternal blood in perimesencephalic hemorrhage on the absence of delayed cerebral ischemia, we compared these 65 patients with 49 patients who had aneurysmal subarachnoid hemorrhage. This control group with aneurysms was selected according to a similar amount of cisternal blood, a comparable level of consciousness on admission, and absence of other factors known to increase the risk for delayed cerebral ischemia. We found that 4 of the 49 patients with aneurysmal hemorrhage developed delayed cerebral ischemia (Fisher's exact test, p = 0.03); therefore the relatively small amount of blood does not account for the absence of delayed cerebral ischemia in perimesencephalic hemorrhage. Patients with a perimesencephalic pattern of hemorrhage and a normal angiogram should be considered to have a distinct subset of subarachnoid hemorrhage and should be excluded from future treatment trials of patients with subarachnoid hemorrhage.

Transient unilateral facial paralysis induced by perimesencephalic non-aneurysmal subarachnoid hemorrhage: A case report and review of the literature

“…It is generally believed that PNSH results from venous or capillary hemorrhage, with the pontine, prepontine, interpeduncular, posterior communicating or thalamic perforating veins being the most likely sources (5). In addition, PNSH is considered to be associated with vein heteromorphosis, and hypertension may also increase the risk of the disease (6).…”

“…Three cases of oculomotor paralysis have been reported in the literature (3,5,6). The first case reported a patient with PNSH that had a third cranial nerve palsy at presentation, this deficit resolved within the first week following SAH (6).…”

“…Long-term outcomes in patients with PNSH are generally improved compared with aneurysmal SAH (4). Symptoms of neurological deficit are rare, and the literature includes three cases of PNSH-induced cranial nerve palsies (3,5,6). The present study describes the first case, to the best of our knowledge, of PNSH-induced transient unilateral facial paralysis.…”

Perimesencephalic Nonaneurysmal Subarachnoid Hemorrhage With Unilateral Third Cranial Nerve Palsy

“…1) Headache was only the first symptom in 65 cases of PNSAH. 5) Only one previous case of PNSAH with unilateral third cranial nerve palsy was reported in 2005. 3) No bleeding source that could directly compress the third cranial nerve was identified in our two cases, so three mechanisms are possible to explain how the cranial nerve palsy developed after PNSAH: indirect compression by the hematoma, focal ischemia by occlusion or collapse of a perforating artery, and vasospasm.…”

Die aneurysmatische Subarachnoidalblutung / Zerebrovaskuläre Arbeitsgruppe der Schweiz (ZAS) und / Schweizerische Herzstiftung (SHS)

“…Tatsache bleibt, dass die Prognose einer SAB ohne Nachweis einer Blutungsquelle in der Regel günstig ist, weil der allgemeine und neurologische Zustand gut sind und keine Nachblutung eintritt. Fast ausnahmslos erholen sich die Patienten innerhalb von zwei bis vier Wochen vollständig [1]. …”