Comparison between perimesencephalic nonaneurysmal subarachnoid hemorrhage and subarachnoid hemorrhage caused by posterior circulation aneurysms

[Non-aneurysmal subarachnoid haemorrhage]

A subarachnoid haemorrhage (SAH) is frequent after a severe head injury. Traumatic-SAH is associated with a bad outcome and may induce cerebral vasospasm. There is no agreement on the treatment based on the amount of traumatic-SAH. Non-aneurysmal SAH accounts for 15% of all causes of non-traumatic SAH. There is a risk of cerebral vasospasm, although less frequent than after aneurysmal rupture. The improvement in imaging techniques has decreased the frequency of idiopathic SAH.

Spontaneous subarachnoid haemorrhage with negative initial angiography: A review of 143 cases

The need for repeat angiography in patients with subarachnoid haemorrhage (SAH) who initially present with a negative angiogram is still debated. The aim of this study was to provide a management protocol for 'angiogram-negative SAH'. From January 1986 to June 2004, 143 patients with SAH were admitted to our institution with negative initial angiograms. We classified the 143 patients into three groups: group I, with no SAH on CT scan, but confirmed by cerebrospinal fluid analysis; group II, with a perimesencephalic pattern of SAH; and group III, with a non-perimesencephalic pattern of SAH. Out of the 143 patients, 103 underwent repeat angiography, and 18 were found to have ruptured aneurysms that were not detected on the initial angiogram (false negative rate: 17.5% overall, 0% in group I, 1.5% in group II, and 45.9% in group III). Repeat angiography should be performed, particularly in patients who have a non-perimesencephalic SAH pattern, for detection of initially unrecognised ruptured aneurysms.

Brain Computed Tomography Angiographic Scans as the Sole Diagnostic Examination for Excluding Aneurysms in Patients with Perimesencephalic Subarachnoid Hemorrhage

OBJECTIVE

In an era in which new computed tomographic scanners approach 100% sensitivity for finding intracranial aneurysms in patients with a perimesencephalic subarachnoid hemorrhage (SAH) pattern, digital subtraction angiography (DSA) is still considered the gold standard. Our purpose was to investigate whether or not computed tomography angiographic (CTA) scanning can be used as the sole diagnostic tool in this setting, and thus replace DSA.

METHODS

Two hundred fifty patients with atraumatic SAH presented to our institute between November 2001 and November 2005. We performed a retrospective search for those patients who had a negative brain CTA scan for aneurysms. Of these, those with a computed tomographic scan showing perimesencephalic SAH at admission were selected, and only those who had DSA performed were included.

RESULTS

We found 30 patients with negative brain CTA scans that matched the perimesencephalic SAH pattern and had DSA performed. The mean time for performing a brain CTA scan was 3.8 +/- 4.4 days, and for DSA 11 +/- 12 days, after the initiation of symptomatology. The interval between CTA and DSA was 5.9 +/- 15 days. There were two patients in whom CTA was considered negative but still suspicious for having an aneurysm; DSA was negative for both.

CONCLUSION

Brain CTA scanning alone is a good and conclusive diagnostic tool to rule out aneurysms in patients presenting with the classic perimesencephalic SAH pattern and thus can replace DSA and its corresponding risks. The latter can be reserved for those patients in whom CTA is doubtful.

Perimesencephalic nonaneurysmal subarachnoid hemorrhage caused by physical exertion

The clinical characteristics of perimesencephalic nonaneurysmal subarachnoid hemorrhage (SAH) caused by physical exertion were analyzed to investigate the causes and mechanisms of perimesencephalic nonaneurysmal SAH. Nine of 209 patients with spontaneous SAH were identified as having perimesencephalic nonaneurysmal SAH. Perimesencephalic nonaneurysmal SAH in four males and three females was precipitated by exertion. Age, sex predominance, type of exertion, symptoms, loss of consciousness during bleeding, clinical grade, angiographic spasm, hydrocephalus, delayed ischemic deficit, rebleeding, hypertension, and outcome were evaluated in these seven patients. Outcomes were assessed using the Glasgow Outcome Scale. Patients showed male predominance (57.1%), relatively young age (mean 50 years), low frequency of hypertension (28.6%), good clinical grade (World Federation of Neurological Surgeons grade I or II), and excellent outcomes including no rebleeding, no symptomatic hydrocephalus, and no delayed ischemic deficits. The type of exertion was swimming in two patients, golfing in two patients, heavy lifting in two patients, and bending forward during gymnastics in one patient. Physical exertion including components of the Valsalva maneuver is an important predisposing factor for perimesencephalic nonaneurysmal SAH. Such physical exertion produces increased intrathoracic pressure, which blocks the internal jugular venous return, resulting in elevated intracranial venous pressure or mechanical swelling of the intracranial veins, and leads to venous or capillary breakdown.

Subarachnoid hemorrhage: neurointensive care and aneurysm repair

Aneurysmal subarachnoid hemorrhage (SAH) is often a neurologic catastrophe. Diagnosing SAH can be challenging, and treatment is complex, sophisticated, multidisciplinary, and rarely routine. This review emphasizes treatment in the intensive care unit, surgical and endovascular therapeutic options, and the current state of treatment of major complications such as cerebral vasospasm, acute hydrocephalus, and rebleeding. Outcome assessment in survivors of SAH and controversies in screening of family members are discussed.