It strikes like a clap of thunder – a sudden jolt of intense head pain that escalates to peak intensity within less than a minute and lasts up to several hours. It could be accompanied by nausea and vomiting.
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It’s a rare occurrence, but a fittingly named thunderclap headache could be an important warning sign from the brain that something is wrong.
“If somebody has a headache that they feel is the worst headache of their life, and within 60 seconds it reaches the maximum intensity, then we recommend that they seek emergency care to get evaluated,” says Zubair Ahmed, MD, a neurologist who specializes in headaches.
A thunderclap headache is most commonly caused by bleeding in the brain that results from a ruptured aneurysm — an abnormal bulge in a blood vessel that bursts. This requires urgent medical attention and treatment.
It could also be the important first sign of an aneurysm that hasn’t ruptured yet but might do so soon, Dr. Ahmed says.
To determine whether an aneurysm is the cause, a doctor will look at the patient’s medical history, take vital signs and do a CT scan of the brain to get a look at the blood vessels in and around the brain. Sometimes, a doctor may need to take a sample of spinal fluid from the back to see if there is blood in the spinal fluid.
Thunderclap headaches could also be triggered by something different called Reversible Cerebral Vasoconstriction Syndrome (RCVS). It’s a sudden narrowing or spasm of a blood vessel sometimes provoked by medications like antidepressants that also requires treatment.
There are also a number of other unusual syndromes that can present in the form of a quick-onset headache, Dr. Ahmed says. Or, it could have no clear cause and be considered a more benign headache disorder.
But because of how serious the potential causes are, it’s important that anyone who experiences a thunderclap headache seek immediate medical attention.