PERIMESENCEPHALIC AND NONPERIMESENCEPHALIC SUBARACHNOID HEMORRHAGES WITH NEGATIVE ANGIOGRAMS

Background: van Gijn and co-workers identified ''Perimesencephalic haemorrhage'' (PM) as distinct, benign, non-aneurysmal subarachnoid haemorrhage. However, there is only one retrospective series of this entity outside the Netherlands. Purpose: to confirm (or not) the benign nature of perimesencephalic subarachnoid haemorrhage by evaluating its clinical course and long-term follow-up in a consecutive series of patients admitted to a University Hospital. Methods: Patients with subarachnoid haemorrhage and negative cerebral angiography admitted between January 1985 and April 1992 were classified according to the distribution of blood on a CT scan performed within 72 hours after onset, in perimesencephalic and non-perimesencephalic haemorrhages. Demographic and clinical data (collected consecutively), complications and long-term follow-up (obtained by chart review and follow-up by mail) were compared in the two groups. Results: Seventy one cases, 36 perimesencephalic and 35 non-perimesencephalic were included. Sex and age distribution were similar in the two groups. A normal examination on admission was the rule in the perimesencephalic group. Only one patient with perimesencephalic haemorrhage had a complication - transient neurological signs during angiography - and there were no deaths or morbidity during follow-up. In the non-perimesencephalic group three patients rebleed, four developed hydrocephalus and two had delayed cerebral ischaemia. Mean duration of follow-up was 27,6 months for the perimesencephalic and 30,8 months for the non-perimesencephalic group. After discharge there was a fatal rebleed in the latter group. Fifteen percent of the subjects (11% of the perimesencephalic group and 20% of the non-perimesencephalic group) retired from work during the follow-up period. Headaches and depression were found in similar percentages (22-25%) in both groups. Conclusions: This study confirms that perimesencepahlic hae morrhage is a distinct entity within the larger group of subarachnoid haemorrhage with negative angiograms, with a good short term and long-term prognosis, and no need for repeated angiographic investigation.