Traumatic subarachnoid haemorrhage: a clinicoradiological and TCD correlation

Twenty five consecutive patients with CT proven pure traumatic subarachnoid haemorrhage (tSAH) were studied, prospectively over a 6 month period. They constituted 2% of all head injuries. Most of the patients (88%) had a mild or moderate head injury at the time of admission, with a mean glasgow comma scale (GCS) of 10.68. The CT scan findings were divided into 3 grades. Grade 1 - blood in hemispheric region only (n=4), grade 2 - blood in basal region only (n=11), grade 3 - blood in both hemispheric as well as basal region (n=10). Transcranial doppler ultrasound (TCD) velocities were recorded in all patients by insonating the middle cerebral artery, internal carotid artery and anterior cerebral artery on both sides. All patients were also subjected to digital substraction angiography (DSA). All patients with mild head injury had normal TCD velocity (<100 cm/sec), while TCD velocities of more than 150 cm/sec were seen only in one patient with severe head injury. Patients with severe head injury were found to have grade 3 tSAH on CT. No statistically significant correlation was found between the CT grade and TCD velocities. Angiographic vasospasm was found in 2 patients with severe head injury only. 90.2% of patients had good outcome at discharge.