Thunderclap Headache: When Secondary Disorders Are the Cause

J. Ivan Lopez, MD


June 03, 2019

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Medscape &

The term "thunderclap headache" (TCH) refers to a headache that has an abrupt onset, reaching maximum intensity in 1 minute or less and lasting for at least 5 minutes. Although this definition, set forth by the International Classification of Headache Disorders,[1] does not specify whether this type of headache is primary or secondary, a diagnosis of a primary TCH can only be made if other diagnoses are excluded. As the name implies, secondary headaches, regardless of presentation, are due to some form of pathology that can be usually found by a good headache history, neurologic exam, and appropriate ancillary testing. However, there are many secondary causes of TCH, some of which can be serious.

Both primary and secondary TCHs may be associated with sexual activity or are induced by exercise. The main diagnostic feature of TCH is the rapidity with which they reach maximum intensity. The pain can be holocephalic or localized. Often TCH is associated with nausea and/or vomiting and depending on the cause of the pain, one can encounter altered cognition/alertness and focal deficits.

Primary TCH is uncommon and should not have the symptoms of altered cognition and focal neurologic deficits. If one or more of these symptoms are part of the symptomatology of these headaches, the clinician must suspect a potentially serious secondary cause. Consequently, patients with TCH require emergent evaluation. Here, we discuss several secondary disorders that could cause TCH.

Secondary Causes of TCH

Approximately 10%-25% of patients with TCH have subarachnoid hemorrhage (SAH).[2] SAH is diagnosed when blood is found in the subarachnoid space, which is between the arachnoid membrane and the pia mater in the brain. SAH should be the first consideration in a patient with TCH because the possibility of morbidity and mortality is high. In fact, the mortality of patients with SAH reaches 50%. The most common cause of spontaneous SAH is rupture of a saccular intracranial aneurysm. Moreover, the most common symptom of a ruptured aneurysm is TCH.

Many patients experience what is called a "sentinel headache." This is a warning headache, before the massive rupture of the saccular aneurysm. It can happen days or weeks before the rupture in up to 10%-40% of these patients. One has to keep in mind that unruptured intracranial aneurysms are found in 3.2% of the population.[2,3,4]

Patients with reversible cerebral vasoconstriction syndrome (RCVS) also may present with a TCH.[2] RCVS is a condition characterized by narrowing of multiple blood vessels, as the name implies. Patients with this condition have multiple areas of arterial vasoconstriction, but there is no aneurysmal SAH. A lumbar puncture (LP) on a patient with RCVS reveals normal cerebrospinal fluid (CSF). There is spontaneous reversal of vasoconstriction usually within 3 months. Patients with RCVS may present with symptoms of an ischemic stroke or SAH.

TCH is present in 20% of patients with dissection in one of the cervical arteries.[2,3] In these cases, there is a tear in the wall of the blood vessel, and the blood dissects the wall of the vessel, as opposed to continuing to flow inside the blood vessel itself. Typically, the pain is ipsilateral to the dissection. Patients can have other symptoms, such as Horner syndrome ipsilateral to the dissection, and even stroke-related symptoms. Horner syndrome is characterized by miosis, ptosis and, depending on the vascular territory affected, facial anhidrosis.

Patients with spontaneous intracranial hypotension present with orthostatic headaches and pain with the Valsalva maneuver, such as coughing, sneezing, straining, or bending. These headaches can be associated with nausea/vomiting, neck stiffness (not to be confused with neck pain), and visual changes of a varied nature.[2,3] It is most frequently caused by a CSF leak in the spine. Imaging often reveals sagging of the brain inside the skull, and nontraumatic subdural hematomas may occur.

TCH is present in 2%-10% of patients with cerebral sinus venous thrombosis (CST).[2] CST happens when a blood clot forms inside one of the venous sinuses in the brain. The pain characteristically gets worse with the Valsalva maneuver. Other associated symptoms include focal neurologic deficits, decreased alertness, and seizures. This condition is more common in women, particularly those who take oral contraceptives or use tobacco and those who are in the puerperium. This condition could be fatal if left untreated.


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