(573) Hydroxocobalamin as a Rescue Therapy for Nimodipine-Induced Severe Refractory Vasoplegia

Introduction: Cerebral vasospasm is a serious complication after aneurysmal subarachnoid hemorrhage (aSAH) leading to secondary neurologic injury. Nimodipine is the only FDA approved medication to reduce poor neurological outcomes after aSAH. Mild systemic hypotension is frequently seen with nimodipine, although severe refractory shock is rare. We present a case of refractory vasoplegia and severe shock after first dose of enteral nimodipine (60 mg), which responded only to hydroxocobalamin (B12) administration.

Description: 59 yo F presented with a sudden onset severe headache. CTH/ CTA showed aSAH due to ruptured Posterior Communicating (PCOMM) artery aneurysm. Worsening hydrocephalus prompted placement of an external ventricular drain. She underwent a frontal craniotomy and L PCOMM clipping. After stabilization in the Neuro-ICU, oral nimodipine (60 mg) was started per aSAH management. Within 30 minutes of the first dose, MAP dropped to 47 mmHg. Fluids and norepinephrine were started. Her MAP remained low (50s) despite escalating doses of norepinephrine and addition of epinephrine and vasopressin. Bedside POCUS showed no cardiac abnormalities or other etiologies of shock. Despite maximum doses of 3 vasopressors, her MAP remained low. She was administered IV B12 as reversal for suspected nitric oxide vasodilation. Within an hour, vasoactive medications were quickly weaned off. A rechallenge of nimodipine was attempted the next day (30 mg) which again precipitated severe vasoplegia. B12 was administered again with almost instantaneous improvement in her MAP. Nimodipine was discontinued and no additional episodes of severe vasoplegia occurred.

Discussion: There is little evidence to guide management of severe vasoplegia due to nimodipine. We describe the first case of nimodipine induced refractory vasoplegia that recurred upon rechallenge with lower dose of nimodipine. Although other etiologies of shock must be ruled out, Intensivists should consider B12 as a lifesaving reversal agent for suspected vasoplegia due to nimodipine.