Investigation of subarachnoid haemorrhage: Does the buck stop with CT?

Background and Aim: In patients suspected of having a subarachnoid haemorrhage (SAH), a normal CT should be followed by lumbar puncture (LP) to detect xanthochromia. We studied the practice of performing a LP following a normal CT in patients with a clinical suspicion of SAH in a District General Hospital. We aimed to assess whether patients were being fully investigated for SAH and whether standards were being met. Methods: This was a prospective study aiming to improve the patient's care by implementing the best practice. We initially recorded CT and LP results of patients with suspected SAH (phase 1) and presented the results to the referring clinicians. After a period of time, data was re–collected to study any change in practice (phase 2). Results: In phase 1, 36 of 61 patients (59.0%) with a normal CT had a subsequent LP compared to 67/104 (64.4%) in the second phase (p=0.51). In the first phase, xanthochromia was detected in 1 of 36 patients (2.8%) who had a LP following a normal CT, compared to 1 of 67 patients (1.5%) in the second phase (p=1.0). Conclusion: Approximately a third of patients with symptoms of SAH in both study periods did not undergo LP following a normal CT scan. This is an important finding, as it is known that a normal CT does not exclude the diagnosis of SAH and by not proceeding to LP, patients have not been fully investigated for a SAH.