Abstract text (incl. figure legends and references)

Objective: Headache disorders constitute 20-30% of inpatient referrals to neurology services in UK. The aim of this study was to identify the headache phenotypes referred for inpatient neurology opinion.

Methodology: All inpatient referrals to the neurology on call service at the Royal Preston Hospital in the year 2019 were reviewed. Cases were identified from the clinical database and categorised into primary and secondary types, according to the International Headache Society classification.

Results: A total of 1114 inpatient referrals were made to neurology services in 2019, of which 255 cases were for a headache disorder (22.9%). Primary headache syndromes made up 158 cases (61.9%), with the remaining cases diagnosed as secondary headache (38.1%). Most primary headaches were diagnosed as migraines (82.3%) followed by tension-type headache (7.6%); 70 cases (44.3%) had a pre-existing diagnosis of primary headache disorder. The major cause of secondary headache was TIA/stroke and idiopathic intracranial hypertension (16.5% each) followed by subarachnoid haemorrhage (11.3%) and infection (7.2%). Both primary and secondary headaches were higher in females (70.0% & 57.7%) compared to males (30.0% & 42.3%).

Majority of patients (74.2%) had been investigated with neuroimaging prior to the referral. Majority received both CT & MRI scans (39.8%), followed by CT only (33.3%) and MRI only (15.7%); 11.2% of patients received no scan.

Conclusion: These findings indicate that a significant proportion of patients with headache referred for inpatient neurology opinion have a primary headache disorder.