Initial assessment and suspicion: In a patient presenting with recent headache and sudden-onset neck stiffness, maintain a high index of suspicion for subarachnoid haemorrhage (SAH), especially if the headache was sudden and severe (thunderclap headache) peaking within 1 to 5 minutes. Neck stiffness is a recognized symptom of SAH and should not be overlooked NICE NG228.
Immediate action: Refer the patient immediately to an emergency department for urgent assessment and investigation, as SAH is a medical emergency requiring prompt diagnosis and treatment NICE NG228.
Diagnostic investigations: The patient should undergo an urgent non-contrast CT head scan, ideally within 6 hours of symptom onset, as this has the highest diagnostic accuracy for detecting SAH NICE NG228.
If CT is positive: Diagnosis of SAH is confirmed if blood is seen in the subarachnoid space on CT. The patient should then be discussed urgently with a specialist neurosurgical centre for further management NICE NG228.
If CT is negative and within 6 hours: Routine lumbar puncture is not required. Consider alternative diagnoses but discuss with a senior clinical decision-maker and seek specialist advice NICE NG228.
If CT is negative and more than 6 hours have passed: Perform a lumbar puncture at least 12 hours after symptom onset to detect xanthochromia, which confirms SAH if present NICE NG228.
Symptom management: Provide effective pain relief, including opioid analgesia if necessary, and document its use as it may affect neurological assessment NICE NG228.
Further imaging: If SAH is confirmed, CT angiography should be performed without delay to identify the source of bleeding and guide treatment NICE NG228.