gms | German Medical Science

Objective: In some patients with subarachnoid hemorrhage (SAH) of a non-perimesencephalic type the reason remains unclear. In these cryptic cases of SAH, despite the subgroup of perimesencephalic SAH, no source of bleeding can be detected in cerebral angiography and spinal MRI. Our objective was to analyze patient characteristics, clinical outcome and prognostic factors in these patients. We also compare the outcome from non-aneurysmal non-perimesencephalic SAH with patients suffering from aneurysmal SAH and perimesencephalic SAH.

Method: From 1999 to 2010, 68 patients suffered from a spontaneous non-perimesencephalic SAH without detection of an aneurysm in repeated digital subtraction angiography (DSA). Clinical and radiological characteristics were entered into a prospectively conducted database. Outcome was assessed according to the modified Rankin Scale (mRS) at 6 months (mRS Score 0-2 favourable vs. 3-6 unfavourable).

Results: 57 of 68 patients were in good WFNS grade at admission (WFNS I-III) (83.8%). Overall, favourable outcome was achieved in 56 of 68 patients (82.4%). In a multivariate analysis, favourable outcome was associated with younger age (p<0.05), absence of Fisher type 3-bleeding (p>0.01), good admission status (p<0.001), and absence of initial hydrocephalus (p<0.01). 43 of the 68 patients had not a Fisher grade 3 bleeding. Of those, 42 patients were in good condition at admission (97.7%) and 40 patients had a favourable outcome (93.0%). In contrast, SAH was graded as Fisher grade 3 in 25 of the 68 patients. 15 of the 25 patients were in good grade at admission (60.0%) and favourable outcome was achieved in 16 patients (64.0%). Compared to aneurysmal SAH, where 94.2% of patients in the ISAT-study had a good grade at admission and 72.8% of the patients achieved a favourable outcome, patients with cryptic SAH achieved the same outcome (p=0.08) although their status at admission was worse (p=0.001).

Conclusions: Non-aneurysmal non-perimesencephalic SAH has a better prognosis compared to aneurysmal SAH. But, whereas patients with a non-Fisher type 3 bleeding had an excellent outcome like patients with perimesencephalic SAH, patients with Fisher type 3 bleeding had a similar risk for a poor outcome like patients with aneurysmal SAH. The present data also suggest that age, poor admission status, and hydrocephalus are prognostic factors for the outcome.