Resumen de Red flags in the evaluation of patients with headache in the emergency department: the good, the bad and the ugly
Background Headache is a frequent complaint in the emergency room. The detection of patients with a secondary life-threatening cause of headache is the main priority. Due to the absence of specific biomarkers, diagnosis of secondary headache disorders is still based on the presence of red flags. In headache medicine, red flags are pieces of information whose presence increases the likelihood of having a secondary headache disorder. There are four major subgroups of red flags, elements related to: the prior history of the patient, an atypical headache phenotype, the presence of unusual symptoms or an abnormal neurological examination.
Objective We aimed to evaluate the frequencies and types of red flags in patients who presented to the emergency room and had a confirmed diagnosis of one of the following secondary headache disorders: cerebral venous sinus thrombosis (CVST) or coronavirus disease 2019 (Covid-19). We also analyzed patients who were discharged from the emergency room with a definite diagnosis of tension-type headache (TTH).
Methods We conducted three observational descriptive studies with cross-sectional design. The studies took place in two third-level academic hospitals and were approved by the Ethics Review Boards of both hospitals. The study population included patients with headache that visited the emergency room. Patients were excluded if another headache disorder was present or if there was some degree of uncertainty in the diagnosis. All potential cases were systematically screened for eligibility during each study period. In each case, two neurologists with expertise on headache medicine assessed for the presence of red flags in each patient who fulfilled the eligibility criteria. A pre-defined questionnaire that included the main red flags was used, based on the International Headache Society and Spanish Society of Neurology proposals.
Results All patients with CVST or Covid-19 presented with at least one red flag. In the case of the TTH study, red flags were also frequent in patients who received a final diagnosis of TTH in the ED discharge report. Among 31 screened patients with CVST, 19 fulfilled eligibility criteria. The most frequent red flags were related to the neurological examination (79%), followed by the presence of other symptoms (68%), an atypical headache phenotype (63%) or the prior history of patients (47%). Among 576 patients with confirmed Covid-19, 104 were included in the study. In this case, the most frequent red flags were the presence of systemic symptoms (100%), followed by an atypical headache phenotype (95%), and prior medical history (76%). Due to the risk of contagion, patients were not physically examined by study physicians. In the third study, among 2132 patients screened, 211 received a TTH diagnosis. In this study, the most frequent red flags were the presence of other symptoms (68%), followed by an atypical headache phenotype (26%), elements of the prior history of patients (13%) and an abnormal examination (7%). Only 10% of patients fulfilled the International Classification of Headache Disorders for TTH.
Conclusion Tension-type headache is over-diagnosed in the emergency department. Patients with a TTH diagnosis presented red flags in 80% of cases, making the TTH diagnosis incompatible. In the present studies, all patients with CVST or Covid-19 who presented to the emergency room with headache had at least one red flag. CVST must be considered in the differential diagnosis of patients with headache and red flags, so the adequate imaging modalities can be performed. In patients with new-onset headache who present with red flags during 2020-2021, the presence of a possible Covid-19 infection should be considered and evaluated.
