Putative pathophysiological mechanisms in recurrent hemicrania from aortic dissection: a case report

BACKGROUND: Transient or permanent neurological symptoms occur in 17–40% of patients with aortic dissection. They can distract from or even mask the underlying life-threatening condition. CASE PRESENTATION: We present the case of a young Caucasian man who consulted for recurrent episodes of stereotyped right-sided sudden-onset severe headache. Upon questioning, he also reported a dull chest pain. Clinical examination and brain magnetic resonance imaging were unremarkable. The concomitant presence of chest pain made us consider aortic dissection. Contrast-enhanced cervico-thoraco-abdominal computerized tomography revealed type A aortic dissection. The patient underwent surgical replacement of the ascending aorta and reported no further episode of headache thereafter. Differential diagnosis of headache in this case includes paroxysmal hemicrania, cluster headache, migraine, trigeminal neuralgia and short lasting unilateral neuralgiform headache with conjunctival injection and tearing. Failure to match diagnostic criteria for any of these primary headache disorders and the resolution of pain episodes following surgery led us to postulate that these new-onset hemicrania episodes were symptomatic of aortic dissection. We hypothesize that aortic wall ischemia could have activated the trigeminovascular system and thereby caused hemicranial pain. Such an effect might be mediated by two different pathways that can be referred to as anatomical and humoral. The humoral hypothesis would posit that ischemia results in synthesis of pro-inflammatory mediators released from the aortic wall into the blood stream, such that they reach the central nervous system and directly stimulate specific receptors. The anatomical hypothesis would imply that pain signals generated by nociceptors in the aortic wall are transferred to the trigeminal ganglion via the cardiac plexus, the first cervical ganglion and the internal carotid nerve such that pain perception is referred to related cranio-cervical dermatomes. CONCLUSION: In cases of isolated headache that does not match key diagnostic criteria for a primary headache entity; a thorough review of systems should be performed to look for symptoms that may indicate symptomatic headache from potentially life-threatening conditions. Neurologists should consider aortic dissection in patients presenting with acute headache and chest pain. Further clinical or experimental studies are required to refute or validate the pathophysiological hypothesis discussed here.