As the authors state, there is ongoing debate over the need for further investigations in patients who have thunderclap headache with normal CT and lumbar puncture results [1].
In some patients, a thunderclap headache may subside and they may not seek medical attention. In the context of SAH, this is termed sentinel headache/ haemorrhage or warning headache.
If the headache is accompanied by a low volume subarachnoid bleed, this will be identified on a CT head or lumbar puncture.
However, as case reports indicate, warning headaches may occur due to aneurysmal enlargement [2,3]. In such cases, plain CT head and lumbar puncture results will be normal.
We agree with the authors that a high-index of suspicion should be maintained in such cases, and if necessary a CT/MR angiogram may have to be performed looking for an aneurysm.
Rapid Response:
Re: Thunderclap headache
As the authors state, there is ongoing debate over the need for further investigations in patients who have thunderclap headache with normal CT and lumbar puncture results [1].
In some patients, a thunderclap headache may subside and they may not seek medical attention. In the context of SAH, this is termed sentinel headache/ haemorrhage or warning headache.
If the headache is accompanied by a low volume subarachnoid bleed, this will be identified on a CT head or lumbar puncture.
However, as case reports indicate, warning headaches may occur due to aneurysmal enlargement [2,3]. In such cases, plain CT head and lumbar puncture results will be normal.
We agree with the authors that a high-index of suspicion should be maintained in such cases, and if necessary a CT/MR angiogram may have to be performed looking for an aneurysm.
1. Thunderclap headache. Dodick DW. J Neurol Neurosurg Psychiatry 2002; 72:6-11.
2. Thunderclap headache: symptom of unruptured cerebral aneurysm. Day JW, Raskin NH. Lancet 1986; 2:1247-8.
3. Unruptured cerebral aneurysm producing a thunderclap headache. Witham TF, Kaufmann AM. Am J Emerg Med 2000; 18:88-90.
Competing interests: No competing interests