Posterior Reversible Encephalopathy Syndrome: Nitroglycerine a Friend or a Foe?

Posterior reversible encephalopathy syndrome (PRES) refers to a clinico-radiological entity with characteristic features on neuroimaging and rapid onset of nonspecific symptoms including headache, seizure, altered consciousness and visual disturbance. It is a neurotoxic state in response to the acute changes in blood pressure leading to vasogenic oedema. It is often but not always associated with hypertension. However, control blood pressure is one of the mainstays of management in such cases. Nitroglycerine (NTG) is a potent vasodilator and is one of the drugs for treatment of hypertensive emergencies. It is found to worsen the cerebral oedema in PRES which is considered due to failure of cerebral blood pressure autoregulation. Here, we report two such cases where patients with PRES deteriorated with NTG infusion. However, the neurological condition of the patients improved drastically the next day. NTG could have further enhanced vasodilation, thus aggravating developing PRES, after autoregulation was lost because of high blood pressure.