Cough syncope with hypertension—caused by brainstem compression?

The commonly accepted pathophysiological changes in cough syncope include a fall in systemic blood pressure, raised intracranial pressure and cerebral ischemia. However, cases of cough syncope without hypotension have been reported in patients with the Arnold–Chiari malformation. We describe a 48-year old man with cough syncopes. Constant blood pressure monitoring revealed hypertension instead of the expected hypotension during the episodes. Attacks of loss of consciousness were associated with motor phenomena, i.e. tonic posturing and tonic spasm. Magnetic resonance imaging revealed compression and displacement of the medulla oblongata by an ectatic and elongated vertebral artery. The commonly accepted mechanism of cough syncope cannot explain the symptoms in our patient because a fall of blood pressure was lacking. Instead, a cough-induced compression of the displaced brainstem may have caused a transient dysfunction of the reticular formation.