Spinal muscular atrophy is an uncommon cause of ketoacidosis, where there is a decrease in muscle mass, an abnormal metabolism of glucose and fatty acids, and changes in neuroendocrine function. These conditions favor the accumulation of keto acids and the development of metabolic acidosis. We report a 26-year-old female, with a history of spinal muscular atrophy type III, consulting for abdominal pain and vomiting lasting one week. She was admitted to the emergency service somnolent and poorly perfused. She had a pH of 6.98, HCO3- of 3.8 mmol/L, pCO2 of 16.4 mmHg, BE of -26 mmol/L, delta ratio of 1.05, anion gap of 31 mEq/L, creatinine of 0.37 mg/dL, sodium of 147 mEq/L, potassium of 3.7 mEq/L, chloride of 112 mEq/L, lactate of 1.2 mmol/L, glucose of 108 mg/dL, albumin of 4.2 g/dL, ketonemia +++, ketonuria +, measured plasma osmolality of 322 mOsm/kg, estimated osmolality of 314 mOsm/kg, toxilab negative, salicylate levels < 3 µg/mL, acetaminophen levels < 1.2 µg/mL. Intravenous hydration and bicarbonate were started, without satisfactory response. Interpreting the clinical picture as a ketoacidosis induced by stress in a patient with spinal muscular atrophy, it was handled with glucose, amino acids, vitamins and trace elements, with a favorable response.