What is the diagnosis and management of a thunderclap headache?

From the Guidelines

Thunderclap headache is a medical emergency that requires immediate evaluation to rule out life-threatening causes, and the diagnosis involves a thorough neurological examination and urgent neuroimaging, typically a non-contrast CT scan followed by a lumbar puncture if the CT is negative, as recommended by the American Heart Association/American Stroke Association in their 2023 guideline 1. The most concerning potential diagnosis is subarachnoid hemorrhage, but other serious conditions include cervical artery dissection, cerebral venous thrombosis, reversible cerebral vasoconstriction syndrome, and pituitary apoplexy. Management begins with stabilizing the patient and addressing the underlying cause. For subarachnoid hemorrhage, neurosurgical intervention may be needed. For primary thunderclap headache (diagnosed only after excluding secondary causes), treatment includes analgesics such as NSAIDs or acetaminophen, possibly combined with an antiemetic like metoclopramide 10mg or prochlorperazine 5-10mg. Some key points to consider in the diagnosis and management of thunderclap headache include:

• The Ottawa SAH Rule, which serves as a method to screen out individuals with a low likelihood of aSAH, and recommends additional testing for patients who present with a severe headache and meet certain criteria, such as age ≥40 y, neck pain or stiffness, witnessed loss of consciousness, onset during exertion, thunderclap headache, or limited neck flexion on examination 1.
• The use of non-contrast CT scan as the initial imaging modality of choice for suspected subarachnoid hemorrhage, due to its superiority in detecting acute SAH 2.
• The importance of considering cerebral venous thrombosis as a potential cause of thunderclap headache, particularly in patients with symptoms such as headache, increased intracranial pressure, and papilledema, and in those with a history of thrombosis or hypercoagulable state 3. The prognosis depends on the underlying cause, with secondary causes carrying more serious implications than primary thunderclap headache, which typically resolves within days to weeks without long-term consequences. It is essential to note that the diagnosis and management of thunderclap headache should be guided by the most recent and highest-quality evidence, and that the American Heart Association/American Stroke Association guidelines provide a comprehensive framework for the evaluation and treatment of this condition 1.

From the Research

Diagnosis of Thunderclap Headache

• Thunderclap headache (TCH) is an excruciating headache that reaches maximal intensity within a minute, with numerous potential etiologies, the most concerning of which is subarachnoid hemorrhage (SAH) due to high morbidity and mortality 4.
• The diagnosis of TCH involves a comprehensive evaluation, including brain computed tomography (CT) and lumbar puncture, to identify the underlying cause and initiate prompt therapy 5.
• If the brain CT is nondiagnostic, further testing such as brain magnetic resonance imaging (MRI) and vascular imaging should be performed to evaluate other possible underlying causes 4.

Management of Thunderclap Headache

• The management of TCH focuses on the specific diagnosis, with treatment and prognosis depending on the etiology of the TCH 6.
• Patients with TCH require an emergent and comprehensive evaluation to identify the underlying cause and to initiate appropriate therapy 5.
• A diagnostic algorithm for patients with TCH includes history and physical examination, head computed tomography (CT) without contrast, CT angiography of the head and neck, and lumbar puncture, with management tailored to the specific diagnosis 7.

Possible Causes of Thunderclap Headache

• TCH has been associated with reversible cerebral vasoconstriction syndrome (RCVS), cervical artery dissection, cerebral venous sinus thrombosis, cerebral infarction, intracerebral hemorrhage, spontaneous intracranial hypotension, intracranial infection, and pituitary apoplexy 4.
• Other possible causes of TCH include sentinel headache, arterial dissection, pituitary apoplexy, intracranial hemorrhage, ischemic stroke, reversible posterior leukoencephalopathy, spontaneous intracranial hypotension, colloid cyst, and intracranial infections 6.
• RCVS has become an important cause of TCH, being diagnosed more frequently with advances in knowledge in the past decade 4.