Sudden severe hyperammonemia and status epilepticus -a case report-
A 39 year-old female patient with ovarian cancer (stage III) underwent TAH with BSO (total abdominal hysterectomy and bilateral salpingo-oophorectomy) at another hospital. During chemotherapy with paclitaxel and carboplatin (day 9, POD 16), she showed melena followed by hematochezia. Physical examination showed abdominal tenderness and rebound tenderness. Neutropenia was present in the blood test. She also had a high fever, tachypnea, hypotension, and cyanosis. She was diagnosed with neutropenic/septic shock due to ascending colon perforation and was transferred to our hospital. Emergent total colectomy was successfully conducted, and the patient was moved to the ICU. The patient was intubated, but alert and oriented before and after surgery.\nThe patient experienced difficulty in weaning from mechanical ventilation due to severe tachypnea and labored breathing. On postoperative day 2, the patient was sedated with midazolam. Neutropenia did not improve in spite of granulocyte colony-stimulating factor (G-CSF) injection. Absolute neutrophil count (ANC) was less than 50/µl. Chemotherapy induced neutropenia and sepsis was suspected, thus G-CSF and antibiotics (Piperacillin/tazobactam) were administered. On postoperative day 5, midazolam was stopped. The patient was extubated but she complained of dyspnea and showed deteriorating levels of consciousness. After reintubation, brain CT and electroencephalography (EEG) were performed which showed no abnormal findings ( and ). Her neurologic status did not show improvement and on the next day, she suddenly developed partial seizure which progressed to generalized tonic-clonic (GTC) seizure. Seizure was controlled with midazolam, ativan, and phenytoin. Brain CT showed diffuse brain swelling () and the EEG test showed severe diffuse cerebral dysfunction (). Laboratory tests indicated severe hyperammonemia (1,325 µg/dl). Arterial blood gas analysis showed respiratory alkalosis with metabolic alkalosis (pH: 7.604, PaCO2: 24.2 mmHg, HCO3-: 27.4 mmol/L), while electrolytes and liver panel were unremarkable. Continuous renal replacement therapy (CRRT) for the treatment of hyperammonemia was not effective (follow-up ammonia level was 1,356 µg/dl). Sodium benzoate was administered as a loading dose followed by a maintenance infusion. Mannitol was administered to attenuate the increased intracranial pressure. The patient showed recurrent episodes of GTC type seizure requiring management of status epilepticus. Midazolam and phenytoin were administered. In spite of medical treatment, further partial seizures occurred accompanied by desaturation and hypotension. The patient subsequently died on postoperative day 8.