PERIMESENCEPHALIC AND NONPERIMESENCEPHALIC SUBARACHNOID HEMORRHAGES WITH NEGATIVE ANGIOGRAMS

Background: van Gijn and co-workers identified ''Perimesencephalic hae morrhage'' (PM) as distinct, benign, non-aneurysmal subarachnoid haemo rrhage. However, there is only one retrospective series of this entity outside the Netherlands. Purpose: to confirm (or not) the benign natu re of perimesencephalic subarachnoid haemorrhage by evaluating its cli nical course and long-term follow-up in a consecutive series of patien ts admitted to a University Hospital. Methods: Patients with subarachn oid haemorrhage and negative cerebral angiography admitted between Jan uary 1985 and April 1992 were classified according to the distribution of blood on a CT scan performed within 72 hours after onset, in perim esencephalic and non-perimesencephalic haemorrhages. Demographic and c linical data (collected consecutively), complications and long-term fo llow-up (obtained by chart review and follow-up by mail) were compared in the two groups. Results: Seventy one cases, 36 perimesencephalic a nd 35 non-perimesencephalic were included. Sex and age distribution we re similar in the two groups. A normal examination on admission was th e rule in the perimesencephalic group. Only one patient with perimesen cephalic haemorrhage had a complication - transient neurological signs during angiography - and there were no deaths or morbidity during fol low-up. In the non-perimesencephalic group three patients rebleed, fou r developed hydrocephalus and two had delayed cerebral ischaemia. Mean duration of follow-up was 27,6 months for the perimesencephalic and 3 0,8 months for the non-perimesencephalic group. After discharge there was a fatal rebleed in the latter group. Fifteen percent of the subjec ts (11% of the perimesencephalic group and 20% of the non-perimesencep halic group) retired from work during the follow-up period. Headaches and depression were found in similar percentages (22-25%) in both grou ps. Conclusions: This study confirms that perimesencepahlic hae morrha ge is a distinct entity within the larger group of subarachnoid haemor rhage with negative angiograms, with a good short term and long-term p rognosis, and no need for repeated angiographic investigation.