Symptom-based screening for acute secondary headaches: A systematised review and introduction of the DIPIH-T list

Background Headaches may indicate serious underlying disorders, yet deciding which patients require further diagnostic evaluation remains challenging. While some clinical information can have diagnostic value, other information has screening value, suggesting secondary headaches without being diagnostic on its own. Objective To compile clinical features with screening value for secondary headaches that do not depend on the pretest probability, and to organise them in categories according to the underlying pathological process and symptom type. Methods Using the International Classification of Headache Disorders, 3rd edition, we identified disorders associated with secondary headaches that require screening because history and clinical examination alone do not allow diagnosis. We then conducted a systematised review searching MEDLINE and relevant literature for headache characteristics, accompanying symptoms, and precipitating factors. To ensure the screening information performed similarly across clinical settings and pre-test probabilities, we focused on symptoms that do not, or at least very infrequently, occur in primary headaches. Results We identified 61 items of clinically relevant screening information: 12 precipitating factors typical of secondary headaches, 47 symptoms and physical examination findings that occur in secondary headaches but not (or at least very infrequently) in primary headaches, and two headache characteristics. Most secondary headache disorders exhibited at least one distinguishing clinical feature, although individual red flags often showed low sensitivity. Structuring the screening information according to the underlying pathological process, we found five domains: neurological Dysfunction, Inflammation/infection, Precipitating factors, Intracranial pressure abnormalities, and Hormonal dysfunction, which resulted in the abbreviation DIPIH. In addition, while thunderclap onset and morning occurrence (temporal features) do not fall into one of these domains, they are still important and should be assessed. These two headache characteristics also occur in primary headaches, suggesting that the setting affects their screening value. Taken together, the collected screening information can be memorised as DIPIH-T. Conclusions Several pieces of information collected through history and examination have screening value and point to specific secondary headaches. The proposed DIPIH-T framework summarises them. However, the sensitivity of some red flags is low, suggesting that this approach alone may not be sufficient for every secondary headache. Nevertheless, this approach offers a cognitive framework upon which future validation studies can build.