Undiagnosed headaches in the emergency department: clinical characteristics and outcomes

Headaches are a common complaint in the emergency department (ED). Understanding the characteristics and outcomes of headaches, especially in undiagnosed patients, is important for improving headache care in the ED. We conducted a retrospective study of 171 headache patients at the ED of Kagawa Prefectural Central Hospital, with a follow-up for the primary and undiagnosed headache groups via telephone to assess long-term outcomes. Primary, secondary, and undiagnosed headaches accounted for 15.2%, 58.4%, and 26.3% of cases, respectively. All life-threatening secondary headaches were successfully excluded with imaging tests performed on 73.7% of cases, despite the low rate of treatment in the ED (18.1%). Among the undiagnosed headache cases, the recurrence of severe headaches was low (11.9%), though awareness of chronic headaches was high (47.6%). Emergency physicians should be aware of the possibility that patients at an ED presenting an undiagnosed headache may include chronic headache patients. Seamless collaboration between the ED and headache specialists is needed to manage undiagnosed headaches in the ED.