Acute Confusion as the Presenting Feature of Hypoglycemia and Lactic Acidosis in an Adult With Known Fructose-1,6-Bisphosphatase Deficiency

We report the case of a 29-year-old woman with genetically confirmed fructose-1,6-bisphosphatase deficiency, an inherited disorder of gluconeogenesis.She had been followed since childhood by a specialized metabolic unit and was brought to the emergency department by a mobile intensive care service because of acute confusion.Her symptoms had begun the previous evening with epigastric pain, repeated vomiting, anorexia, and intense asthenia.Consequently, she had eaten almost nothing for approximately 20 hours before the onset of confusion.The Glasgow Coma Scale (GCS) score recorded during the pre-hospital assessment was 8, with a capillary blood glucose concentration of 0.4 g/L (2.2 mmol/L), which was partially corrected during transfer.On arrival, her GCS score was 10.She had no focal sensorimotor deficit, and her pupils were equal and reactive.Her respiratory rate was 26 breaths per minute, peripheral oxygen saturation was 98% on room air, blood pressure was 140/80 mmHg, and heart rate was 120 beats per minute.The abdomen was soft and non-tender.Arterial blood gas analysis showed severe metabolic acidosis with appropriate respiratory compensation (pH 7.185; bicarbonate, 6.3 mmol/L) and a lactate concentration of 6.49 mmol/L.The full blood count showed moderate leukocytosis with neutrophil and monocyte predominance without anemia.Computed tomography of the chest, abdomen, and pelvis, performed after treatment had been initiated to exclude an intercurrent precipitating condition, was normal.She was treated with intravenous 30% dextrose, followed by a continuous intravenous dextrose infusion, and was admitted to the intensive care unit.Her consciousness returned to a GCS score of 15, and the acid-base disturbance corrected in parallel.Mechanical ventilation was not required.She was discharged from the intensive care unit after 48 hours, with complete neurological recovery.This episode did not represent a new diagnosis but rather an acute decompensation of an already known metabolic disease, precipitated by vomiting and a fast of approximately 20 hours.In a patient with a known disorder of gluconeogenesis, acute confusion following vomiting or reduced oral intake should prompt consideration of a hypoglycemic and lactic acidosis crisis until proven otherwise.Bedside glucose measurement and arterial blood gas analysis can establish the diagnosis within minutes, and intravenous dextrose is the treatment for both abnormalities.