This case presents a patient with ectopic secretion of adrenocorticotrophic hormone from a carcinoid tumor resulting in severe hypertension, posterior reversible encephalopathy syndrome (PRES), and refractory status epilepticus. Secondary hypertension may be difficult to identify in critically ill patients. Severely uncontrolled hypertension presenting with PRES caused by Cushing syndrome is rare but should be considered. Management requires the correct diagnosis and specific treatment. A missed or delayed diagnosis can lead to serious consequences and disability.