Thunderclap Headache: When Secondary Disorders Are the Cause

J. Ivan Lopez, MD


June 03, 2019

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Evaluating the Patient With TCH

In addition to taking a good history of the symptomatology of the headache, the clinician should perform a neurologic exam with special attention to identifying whether the patient has any focal weakness or cranial nerve palsy.

As mentioned previously, the first diagnostic consideration in patients with TCH should be SAH, secondary to a ruptured intracranial aneurysm. Usually, these patients present to the emergency department with a severe headache that reaches maximum intensity within 1 minute. These patients should undergo nonenhanced CT of the head. If there is an SAH, the CT will often show areas of increased density in the subarachnoid space.

If the CT shows no evidence of SAH, a physician should perform an LP, looking for blood. The yield of LP in these circumstances is higher if performed within the first 12 hours after onset of symptoms.

One should send the CSF for a cell count. If the red blood cell count does not change between tubes 1 and 4, one is probably dealing with SAH.[2,4] The laboratory can perform a cell count, whereby the technologist counts how many cells/mL are in each tube. If there is a decrease in the number of red blood cells between tubes, then the cause is probably a traumatic tap. Another important diagnostic tool is to measure the opening pressure when performing the LP. The clinician does so using a manometer while the patient is lying in the lateral decubitus position. Increased opening pressure is consistent with SAH.

If CT of the brain and LP are normal, there is an extremely low rate of SAH. Nevertheless, there are other causes of TCH. Therefore, additional testing should include MRI/MRA of the brain, and possibly digital subtraction angiography and magnetic resonance venography, depending on what the clinician suspects the reason for the TCH may be on the basis of the presentation and neurologic examination findings.

Treatment Options

Treatment for patients with TCH depends on the cause. For patients with primary TCH associated with sexual activity or exercise-induced headaches, sometimes propranolol or indomethacin can help. These are considered primary headaches because no structural cause can be found after extensive investigation.[1] In the first case, the headache starts during sexual excitement or orgasm. In the second type, the headache starts at the onset of exercise or during strenuous effort, such as weight lifting or sprinting.

However, TCH can be the presenting symptom of SAH, which carries high morbidity and mortality.[2] Every patient with TCH should undergo CT of the head and LP, if the CT is unyielding. If both these tests are normal, the history and examination findings show no focal deficits, and there is no decreased alertness or seizures, then these patients can be followed in an outpatient clinic for more detailed headache history, exam, and possibly other ancillary testing.

On the other hand, if evidence of SAH is found by CT or LP, the clinician should suspect that the patient has experienced a ruptured aneurysm, and this condition must be dealt with immediately. In this case, the patient should be referred to a neurosurgeon or an interventional neurologist or radiologist for clipping or endovascular coiling of the aneurysm. Clipping and endovascular coiling are procedures that may help prevent repeated bleeding or ruptures.

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