Delirium in acute subarachnoid haemorrhage.

BACKGROUND: Delirium may be a presenting feature in acute subarachnoid haemorrhage (SAH). The aim of this study was to investigate the risk factors for delirium in acute SAH and to analyse the relation between delirium and location and amount of haematic densities and hydrocephalus.
METHODS: We assessed delirium in a sample of 68 consecutive patients with acute (< or =4 days) SAH (33 aneurysmal, 33 non-aneurysmal, including 9 with perimesencephalic haemorrhage), before aneurysmal treatment, using DSM-IV-R criteria and the Delirium Rating Scale (DRS). DRS scores were related to: (1) the total amount of haematic densities at 10 basal cisterns/fissures and in the 4 ventricles, using a validated rating scale, (2) the haematic densities in the prepontine cistern and the convexity of the brain and (3) hydrocephalus, using the bicaudate index, obtained from a review of admission CT scans.
RESULTS: Eleven acute SAH patients presented with delirium. Older age (U = 316.5, p = 0.04), alertness disturbance (chi(2) = 5.1, p = 0.02, OR = 7.6, 95% CI = 1.5-37.3), aphasia (U = 61.5, p = 0.007) and a Hunt and Hess score >2 (U = 362.5, p = 0.02) were associated with delirium. Higher amounts of intraventricular haematic densities (chi(2) = 4.43, p = 0.04, U = 158, p = 0.001) and hydrocephalus (U = 215, p = 0.009) were also associated with higher DRS scores. Two delirious patients had basofrontal haematomas.
CONCLUSIONS: Delirium was detected in 16% of acute SAH patients. Intraventricular bleeding, hydrocephalus and basofrontal haematomas contribute to the pathogenesis of delirium, through damage to anatomical networks subserving sustained attention, declarative memory and the expression of emotional behaviour.