PC1205: Subacute Combined Degeneration in a Child with Autism Spectrum Disorder, Food Aversion, and Psychosocial Stressors: A Case Report

Introduction: Subacute Combined Degeneration of the spinal cord from vitamin B12 deficiency is rarely found in resource-rich countries and is typically caused by pernicious anemia, gastrointestinal malabsorption, reduced dietary intake, and rare genetic disorders. Children with Autism Spectrum Disorder (ASD) can have restrictive eating patterns that put them at risk for nutritional deficiencies. Psychosocial stressors may exacerbate such feeding challenges.

Case Description: A 16-year-old male with ASD, chronic functional constipation, textural food aversions, frequent emesis, and obesity presented with a five-month history of progressive gait disturbance, sensory changes, and eventual inability to ambulate. His anxiety, stereotyped behaviors, and food aversion acutely worsened after several psychosocial stressors that included a prolonged illness in his mother and a return to in-person schooling after a year of virtual learning during the COVID-19 pandemic. He lost 33kg in weight over eight months. He was prescribed famotidine and omeprazole without improvement. Initial neurological examination revealed anxious affect, ataxic gait, intention tremor in both arms, positive Romberg sign, and symmetric trace deep tendon reflexes in all extremities. Diagnostic testing was notable for vitamin B12 level of 172 pg/mL (normal >300 pg/mL); normal CBC, folate, TSH, vitamin E, and copper levels; negative Celiac panel; negative Intrinsic Factor Antibodies; EGD revealing esophagitis with lower esophageal ulceration; and normal Head CT. He was prescribed oral B12 supplementation 1000 mcg daily and weekly intramuscular B12 injections but symptoms continued worsening after four weeks. Severe constipation and constant emesis over ten days prompted inpatient admission for dehydration and severe protein-calorie malnutrition with associated electrolyte abnormalities. Despite normalization of his B12 level at the time of admission, sedated MRI of the brain, cervical, and thoracic spine demonstrated extensive signal abnormality in the cerebellum and dorsal columns of the spinal cord, consistent with subacute combined degeneration (Picture 1). A gastrostomy tube was placed to ensure adequate nutrition, and he was maintained on a consistent bowel regimen with eventual stabilization. A multidisciplinary approach with psychiatrists, psychologists, and child life specialists was taken to help manage his anxiety. After 47 days in the hospital, he was discharged to an acute rehabilitation facility for continued physical, occupational, and speech therapies.

Discussion: Patients with ASD and restrictive eating patterns are at risk for significant morbidity from nutritional deficiencies. When new psychosocial stressors are identified during a healthcare visit, particular attention should be paid to changes in eating habits and the potential risk for nutritional deficiencies. B12 deficiency is rare but may lead to devastating neurological complications such as subacute combined degeneration.

Conclusion: Nutritional screening for children with ASD is imperative for those with food aversion, especially after stressors that may trigger worsening of behaviors. Prompt intervention can prevent significant morbidity in this population.