Neurological deficits after brain surgery are not uncommon, and correct and prompt differential diagnosis is essential to initiate appropriate treatment. We describe a patient suffering from loss of consciousness due to hyperammonemia, following valproic acid treatment after surgery for an unruptured cerebral aneurysm. A 57-year-old female patient underwent successful aneurysmal neck clipping to correct an unruptured aneurysm. Her postoperative course was good, and she received anti-epileptic therapy (valproic acid) and a soft diet. Within a few days the patient experienced mental deterioration. Her serum valproic acid reached toxic levels (149.40 mg/L), and serum ammonia was fifteen times the upper normal limit (553 mmol/L; normal range, 9-33 mmol/L). After discontinuation of valproic acid and with conservative treatment, the patient recovered without any complications. Valproate-induced hyperammonemic encephalopathy is an unusual but serious neurosurgical complication, and should not be disregarded as a possible cause of neurological deficits after neurovascular surgery. Early diagnosis is crucial, as discontinuation of valproic acid therapy can prevent serious complications, including death.
Ammonia ; Aneurysm* ; Brain ; Diagnosis, Differential ; Diet ; Early Diagnosis ; Female ; Humans ; Hyperammonemia ; Intracranial Aneurysm ; Middle Aged ; Neck ; Reference Values ; Unconsciousness ; Valproic Acid

Stellate ganglion block (SGB) is a procedure that is widely used for many diseases associated with sympathetically-maintained pain in the head, neck, and upper extremities. Various hemodynamic changes may occur after SGB. Among them, we experienced two patients who developed highly increased blood pressure after SGB. We suspect that the spread of local anesthetics produced parasympathetic blockade of the vagus nerve, an imbalance between the sympathetic and parasympathetic activities and deafferentiation of the glossopharyngeal and vagus nerve, which both innervated the carotid sinus, as the mechanism of this increased blood pressure.
Anesthetics, Local ; Blood Pressure ; Carotid Sinus ; Head ; Hemodynamics ; Humans ; Neck ; Stellate Ganglion ; Upper Extremity ; Vagus Nerve