Frequency of perimesencephalic sub arachnoid haemorrhage in our hospital

Aim: Spontaneous sub arachnoid haemorrhage (SAH) is diagnosed by imaging studies which mainly is by a computerised tomography (CT) of the brain. The cause of spontaneous SAH is most commonly due to a rupture in the vascular structures supplying blood to the brain which is detected by a CT angio of the brain. This study is hence aimed at analysing the incidence and frequency of angio negative SAH in patients admitted in our hospital. Materials and Methods: This is a retrospective and a prospective study where 32 patients were detected either with CTA or DSA or both to be having spontaneous angio negative SAH. They were clinically graded based on the WFNS scale (6) and radiologically by the Fischer score of their plain CT brain. Patients diagnosed with classical SAH and had a structural vascular abnormality were managed as per protocol of either endovascular coiling or surgical clipping. Patients who were diagnosed to have a negative angio imaging studies were given supportive treatment. Results: During the said period 124 patients were diagnosed to have SAH at our centre. 3 of them died before any evaluation. 33 out of 121 were diagnosed to be angio negative. The male to female ratio was nearly equal with 18 female and 15 males. The ages ranged from 40-80 years. 1 of them was subsequently diagnosed to have a p.comm a aneurysm on a repeat DSA 4 weeks later to the ictus and underwent successful endovascular coiling. Of the 32 who were angio negative on the repeat imaging done 4 weeks later, 2 developed hydrocephalus. 1 underwent right V-P Shunt but the other was put on an EVD and succumbed to sepsis. Conclusion: The entity of PMSAH had a good outcome in our study the incidence being 26.4% and the mortality was 1 (3%) this being not directly due to the SAH. Based on the CT images and the criteria stated the patients can’t be labelled PMSAH. A repeat vascular imaging at least 4 weeks after the primary ictus is necessary. Keywords: Spontaneous sub arachnoid hemorrhage, CT angio negative brain hemorrhage.