A 16-year-old boy is evaluated for progressive gait instability, dysmetria, and dysarthria for the past several years. The patient enjoys basketball but can no longer play due to his worsening symptoms. He is worried as his brother died of a neurologic disease at age 21. Physical examination of the lower extremities reveals bilateral motor weakness and loss of deep tendon reflexes, joint position, and vibration sense. MRI of the brain and spine shows degeneration of the posterior columns and spinocerebellar tracts. Which of the following conditions has clinical manifestations that closely resemble this patient's disease?

Question

A 16-year-old boy is evaluated for progressive gait instability, dysmetria, and dysarthria for the past several years.  The patient enjoys basketball but can no longer play due to his worsening symptoms.  He is worried as his brother died of a neurologic disease at age 21.  Physical examination of the lower extremities reveals bilateral motor weakness and loss of deep tendon reflexes, joint position, and vibration sense.  MRI of the brain and spine shows degeneration of the posterior columns and spinocerebellar tracts.  Which of the following conditions has clinical manifestations that closely resemble this patient's disease?

Quizplus · Accepted Answer

Vitamin E is a lipid-soluble, antioxidant vitamin that is widely available in the diet. Vitamin E deficiency is rare but may occur in patients with fat malabsorption and abetalipoproteinemia. The most notable manifestations include hemolysis and neurologic dysfunction (due to free radical damage of cell membranes). Neurologic symptoms of vitamin E deficiency closely mimic Friedreich ataxia (an autosomal recessive degenerative condition) as many of the same areas in the nervous system are affected. Specifically, patients with either condition may have ataxia (due to degeneration of spinocerebellar tracts), loss of position and vibration sense (due to degeneration of the dorsal columns), and loss of deep tendon reflexes (due to peripheral nerve degeneration). Vitamin B12 deficiency may also present similarly due to subacute combined degeneration of the dorsal and lateral spinal columns. (Choice A) Unlike Friedrich ataxia, acute intermittent porphyria does not result in progressive spinal cord degeneration. Instead, it usually causes intermittent acute attacks of abdominal pain and peripheral neuropathy. (Choice B) Lead intoxication is seen in children more often than adults. It manifests with irritability, loss of developmental milestones (in infants), or learning problems (in older children). Gastrointestinal symptoms (eg, constipation, nausea, abdominal pain) also occur. (Choice C) Poliomyelitis causes damage to the anterior horn cells and leads to asymmetric flaccid paralysis and hyporeflexia. Sensation is typically preserved. (Choice D) Creutzfeldt-Jakob disease is a prion disease that presents with rapidly progressive dementia and myoclonic jerks of the extremities. (Choice E) Thiamine (vitamin B1) deficiency occurs in patients with alcohol use disorder or malnourishment. It is associated with peripheral neuropathy, high-output cardiac failure, and Wernicke encephalopathy (eg, ataxia, confusion, ophthalmoplegia). Educational objective: Vitamin E is a lipid-soluble vitamin that has antioxidative properties. Neurologic symptoms of vitamin E deficiency closely mimic Friedreich ataxia and include ataxia (due to degeneration of spinocerebellar tracts), loss of position and vibration sense (due to degeneration of the dorsal columns), and loss of deep tendon reflexes (due to peripheral nerve degeneration). __________ References: Cerebellar ataxia due to isolated vitamin E deficiency. (http://www.ncbi.nlm.nih.gov/pubmed/15681888)

A 16-Year-Old Boy Is Evaluated for Progressive Gait Instability, Dysmetria