Episodic migraine associated with postural orthostatic tachycardia syndrome and vasovagal syncope: migraine triggers neuromediated syncope.

Dr. Elcio Juliato Piovesan – Hospital de Clínicas da UFPR Rua General Carneiro 181 / 12 andar / Sala 1236 80060-900 Curitiba PR Brasil. E-mail: [email protected] Migraine is a common episodic headache disorder characterized by attacks consisting of various combinations of headache, neurologic, gastrointestinal and autonomic symptoms. Autonomic symptoms, such as a cold feeling, increased urination, anorexia, diarrhea, constipation and fluid retention, can occur during the premonitory phase, and nausea, vomiting, diarrhea, cutaneous vasoconstriction (pallor), vasodilation (flushing), piloerection and diaphoresis can occur during the pain phase. Migraine patients with accompanying autonomic symptoms seem to experience their pain more unilateral and more severe than non autonomic migraine patients. Studies of autonomic nervous system dysfunction in migraine have been performed. Cardiovascular tests, vasomotor reactions to temperature changes and responses to pharmacological tests, and changes in biochemical parameters suggest abnormalities (hypoor hyperfunctioning) of both the sympathetic and parasympathetic nervous systems. These inconsistent findings may be explained by different types of autonomic dysregulation. Syncope and migraine are both highly prevalent in the general population. Both disorders occur together more frequently than chance would predict, i.e., they are comorbid. Studies using the orthostatic (tilt) test suggest that migraine patients have vagal hyperactivity and α-sympathetic system hypoactivity. Migraineurs may have a genetic predisposition leading to autonomic nervous system (ANS) dysfunction. The link between migraine and abnormal ANS function is unclear. ANS dysfunction may be involved in both increased susceptibility to migraine headaches and increased response to triggers. Migraine patients with typical autonomic symptoms, such as postural orthostatic tachycardia syndrome (POTS) and vasovagal syncope (VS), as well as patients with migraine with prolonged aura, are potential candidates for genetic studies. Mitochondrial dysfunction may play a role in migraine pathophysiology. It is not known whether the mitochondrion (encoded by the nuclear and mitochondrial genomes) is the primary site of the dysfunction, or whether the mitochondrial disturbance occur secondary to another cause. Mitochondria may play a role in the genesis of migraine, especially in these groups (migraine plus autonomic symptoms). Connecting networks exist between pain and autonomic functions in the brain (Fig 1); thus pain can produce autonomic symptoms. We describe a group of patients in whom autonomic symptoms (POTS and VS) occurred only during migraine attacks. We also studied the presence of the mitochondrial DNA (mtDNA) A3243G point mutation, common in patients with mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes (MELAS).