The Thunderclap Headache: Approach and Management in the Emergency Department.

<bold>Background: </bold>A thunderclap headache (TCH) is a severe headache reaching at least 7 (out of 10) in intensity within 1 min of onset, and can be the presenting symptom of several conditions with potential for significant morbidity and mortality.<bold>Objective Of the Review: </bold>This narrative review evaluates the various conditions that may present with TCH and proposes a diagnostic algorithm for patients with TCH.<bold>Discussion: </bold>TCH is a symptom associated with several significant diseases. The most common diagnosed condition is subarachnoid hemorrhage (SAH). Other diagnoses include reversible cerebral vasoconstriction syndrome, cerebral venous thrombosis, cervical artery dissection, posterior reversible encephalopathy syndrome, spontaneous intracranial hypotension, and several others. Patients with TCH require history and physical examination, with a focus on the neurologic system, evaluating for these conditions, including SAH. Further testing often includes head computed tomography (CT) without contrast, CT angiography of the head and neck, and lumbar puncture. Evaluation must take into account history, examination, and the presence of any red flags or signs suggestive of a specific etiology. An algorithm is provided for guidance within this review incorporating these modalities. Management focuses on the specific diagnosis. If testing is negative for a serious condition and the patient improves, discharge home may be appropriate with follow-up.<bold>Conclusions: </bold>Patients presenting with TCH require diagnostic evaluation. History and examination are vital in assessing for risk factors for various conditions. Focused testing can assist with diagnosis, with management tailored to the specific diagnosis. [ABSTRACT FROM AUTHOR]