Michael Eller; Peter J Goadsby

Disclosures

Expert Rev Neurother. 2013;13(3):263-273. 

In This Article

Headache of Abrupt Onset

Headache that comes on suddenly and with great severity has become known as thunderclap headache. Some space will be devoted to the differential diagnosis of this most worrisome symptom. The term was coined in 1986 in describing the pain that can accompany an unruptured aneurysm – the so-called sentinel headache.[52] This occurs in 10-43% of patients who ulitimately re-present with a with a confirmed aneurysmal SAH,[53] and is commonly misdiagnosed.[54,55] Features of SAH such as nuchal rigidity, decreased level of consciousness and focal neurological signs are often absent.[56] Thunderclap headache is also a characteristic feature of SAH; this diagnosis must be urgently excluded. Readers are directed to a number of excellent reviews regarding the work-up of thunderclap headache and SAH.[54,57]

In one prospective series, these CT brain scans and cerebrospinal fluid analysis were found to be negative in 89% of patients who presented with excruciating headache of abrupt onset.[58] These patients require an MRI brain with magnetic resonance angiography and magnetic resonance venography to exclude a host of other causes (Box 3), particularly in the presence of concerning signs or symptoms. Care should be included when imaging the extracranial carotid arteries in this work-up, as carotid dissection can precipitate an abrupt onset headache 20% of the time, albeit typically accompanied by neck pain.[59,60] If all the tests are ultimately negative in a bland clinical context, the diagnosis of primary thunderclap headache is appropriate.[5] This syndrome of unknown etiology can cause recurrent symptoms – accounting for 23% of the non-SAH patients who presented with thunderclap headache in one series.[58]

Reversible cerebral vasoconstriction syndrome is an important cause of thunderclap headache.[61] Its etiology remains obscure, but is speculated to relate to altered catecholamine levels, or response of the cerebral vasculature to a sympathetic stimulus. Reversible cerebral vasoconstriction syndrome is described by segmental narrowing of intracranial arteries that are reversible with serial imaging over months, and are demonstrable using both CT and MR modalities.[62] Ischemic and hemorrhagic stroke can result, as well as the characteristic finding of convexal SAH in younger patients.[63] It is often precipitated by the use of vasoactive substances such as cocaine or phenylephrine.[61]

Stroke is a very important cause of new headache. This symptom complicates stroke up to 25% of the time,[64] and can be abrupt in onset.[58] This is particularly pertinent in the older population, in which stroke is more common. Factors that increase the likelihood of headache accompanying ischemic stroke include: relative youth, female sex, history of migraine and a posterior circulation event, particularly in the cerebellum.[6]

Headache is almost a ubiquitous feature of patients with cerebral venous thrombosis, but usually with gradual tempo of onset, and accompanied by additional signs and symptoms. However, it can present with thunderclap headache in up to 13% of patients,[65] ultimately accounting for a very small percentage of patients that present with acute headache.[58] Spontaneous intracranial hypotension can present abruptly, with a peak incidence at the age of 40.[66] Other causes of acute onset headache include: pituitary apoplexy,[67] retroclival hematoma,[68] colloid cyst of the third ventricle,[69] infection[70] and posterior reversible encephalopathy syndrome – often associated with the peripartum period and malignant hypertension.[71]

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