Neuro Diseases: Thunderclap Headache

Thunderclap Headache is the term used when a person experiences an extremely severe headache (HA) and that builds up very rapidly.

Some patients describe this as the worst headache in their life. On a scale of 1 to 10, where 10 is the highest intensity of HA it is not unusual for patients to grade it as around 10, or sometimes even more than 10, so that explain how severe this HA could be.

This type of HA builds up very rapidly say in few seconds, minutes and generally less than an hour most often.

Well the severity of HA may not always correlate with the underlying cause. Patients can have the most severe HA of their life but investigations may prove that there is nothing serious to explain such HA.

Having said that we need to be aware that such severe HA may be associated with myriad grave conditions too, and some common examples include;

• Subarachnoid hemorrhage (SAH)
• Bleeding into brain tissue (e.g. AVM, brain tumor related etc)
• Bleeding into pituitary gland (pituitary apoplexy)
• Clot in the venous system of the brain (CVT or cerebral venous thrombosis)
• Dissection (tear in the wall) of arteries supplying the brain (carotid or vertebrobasilar)
• Extremely high blood pressure
• Brain infections like meningitis
• Colloid cyst blocking CSF flow etc

These headaches should be taken seriously and properly investigated. The presence additional neurological manifestations like stiff neck, focal neurological deficits, cranial nerve deficits, fever, high blood pressure etc should hint the possibility of some underlying pathologies rather than severe migraine, tension headache or psychological causes etc.

A non contrast head CT is generally the first and the best test in evaluating these severe headaches. Giving a contrast will improve the yield however not all cases require that. If you are suspecting a tumor related bleed, cerebral venous thrombosis etc contrast is very helpful.

An MRI of the brain may not be necessary immediately but eventually may be required for some patients where CT finding was not helpful or sufficient.

A spinal tap (lumbar puncture) and spinal fluid analysis is required in some patients. The fluid may show findings suggestive of SAH, neuro infections, etc.

Several blood & urine tests may also be required based on the individual condition we are suspecting e.g. pheochromocytoma.

If all obvious causea are ruled out after a thorough and extensive investigations then we may also suspect idiopathic thunderclap headache, this name is given if there are no identifiable causes and this is not a serious condition although the headache is extremely severe so it needs prompt attention.

The treatment focuses on the HA per se as well as what is causing the HA. HA may be treated with NSAIDs (non steroidal anti-inflammatory drugs like indomethacin, diclofenac, ketorolac), opioids (e.g. demerol, or morphine shot) etc.

The management of the cause of the HA depends upon the cause itself. For example a cerebral ruptured aneurysm may be treated with clipping, coiling or excising it. CVT may be treated with blood thinners, adequate hydration etc. Hypertensive emergency is treated with carefully lowering the blood pressure. Meningitis is treated with appropriate antibiotics.

A neurologist is frequently involved in the care of patients with Thunderclap Headache.