Amoolya Vayalapalli, MD
Medical Student
Medical College of Georgia
Duluth, Georgia, United States
Kimberly Stroud, MD
Pediatrician
Northeast Georgia Physicoans Group
Toccoa, Georgia, United States
Cobalamin C Deficiency (Cbl-C)
Case Description: A 9-year-old male with a history of congenital nephrotic syndrome secondary to diffuse mesangial sclerosis was evaluated for five months of changes in behavior and regression at school. The patient further regressed after a dental procedure with laughing gas in which he became increasingly agitated and confused, spoke only in 1-2 word phrases while also presenting with bowel incontinence and hallucinations. Work up revealed mild low parenchymal volume changes on MRI; mild diffuse encephalopathy on EEG; and increased methylmalonic acid (MMA) and total homocysteine revealing a Cbl-C upon genetics testing. Treatment included betaine and hydroxocobalamin with folic acid supplementation. At admission to the Day Rehab Program (DRP), the patient presented with encephalopathy; aphasia; incoordination; impaired functional mobility, gait, and endurance; hypotonia; and symbolic dysfunction.
Discussions: Cbl-C prevents conversion of dietary vitamin B12 into methylcobalamin and adenosylcobalamin causing an accumulation of MMA and homocysteine and decreasing methionine synthesis. The disease process can be distinguished by an early onset with a multisystem disease or by a late onset of slowly progressing neurological sequelae with regression, possible seizures, and evidence of symbolic dysfunction. Acute medical management of the metabolic derangements and the subsequent clinical course are fairly established. However, long term rehabilitation to abridge the gap in neurologic regression varies from patient to patient. In our case, the patient required help with re-acquiring complex motor skills, progressive ambulation, swallowing, cognition, communication skills, bowel and bladder management, and emotional/ behavioral support.
Conclusions: This case highlights Cbl-C and the subsequent manifestations of neurologic sequelae requiring close rehabilitation care and monitoring. The aggressive multidisciplinary approach to rehabilitation for these patients helps them reintegrate the skills that were previously lost to regression and conditions them towards independence.
