Nondiabetic Ketoacidosis in a Patient With Spinal Muscular Atrophy Type II

Background: Spinal muscular atrophy (SMA) is an autosomal recessive disorder characterized by insufficient levels of the survival motor neuron protein; this promotes progressive loss of motor neurons leading to muscular atrophy. Patients with SMA also have metabolic abnormalities that can predispose them to develop ketoacidosis. The objective of this report is to describe a 51-year-old female with SMA type II who presented with nondiabetic ketoacidosis requiring hospitalization. Case Presentation: A 51-year-old female with SMA type II presented with 1 day of diarrhea, decreased oral intake, nausea, and generalized abdominal pain. Her neurologic examination was remarkable for diffuse muscle atrophy with flaccid tone and 0/5 upper extremity and lower extremity reflexes. Laboratory evaluation showed a pH 7.09 (7.35-7.45), pCO₂ 26 mm Hg (35-45 mm Hg), bicarbonate 8.3 mmol/L (21-28 mmol/L), glucose 110 mg/dL (65-99 mg/dL), anion gap 28 mEq/L (7-15 mEq/L), and beta-hydroxybutyrate 7.39 mmol/L (0.02-0.27). The patient received intravenous fluid with dextrose and insulin infusion, and her laboratory values improved after 2 days of treatment with resolution of ketosis. Discussion: SMA has significant neuromuscular manifestations due to the loss of motor neurons. However, metabolic and endocrine abnormalities have been described. These abnormalities predispose them to glucose intolerance, insulin resistance, and increased ketone production in times of stress. Conclusion: Our case demonstrates that despite SMA being mainly a neuromuscular disorder, endocrine abnormalities have been described in these patients. These abnormalities should be considered for appropriate diagnoses and management of the associated metabolic comorbidities.