Friedreich ataxia vs Vitamin E deficiency and subacute combined degeneration
How to tell Friedreich ataxia and Vitamin E deficiency and subacute combined degeneration apart when a board question makes them look alike.
Friedreich is inherited early ataxia plus cardiomyopathy; vitamin E is deficiency mimic; B12 SCD is posterior column/lateral tract myelin disease with B12 labs.
Side by side
Friedreich ataxia causes childhood/adolescent progressive gait ataxia, dysarthria, loss of vibration/proprioception, absent deep tendon reflexes plus extensor plantar responses, pes cavus, scoliosis, diabetes, and hypertrophic cardiomyopathy.
Vitamin E deficiency can mimic Friedreich-like spinocerebellar/posterior column disease; subacute combined degeneration from B12 deficiency causes posterior column and lateral corticospinal tract dysfunction with macrocytic anemia or neuropathy clues.
GAA repeat expansion in frataxin causes mitochondrial dysfunction and degeneration of dorsal columns, spinocerebellar tracts, corticospinal tracts, and peripheral nerves.
Vitamin E deficiency reduces antioxidant protection in neurologic tissue; B12 deficiency impairs myelin maintenance in posterior columns and corticospinal tracts.
GAA repeat expansion, absent reflexes plus extensor plantar responses, cardiomyopathy, pes cavus, scoliosis, diabetes, and early-onset progressive ataxia support Friedreich ataxia.
Low vitamin E supports vitamin E deficiency; low B12, high methylmalonic acid, macrocytosis, and dorsal column dysfunction support subacute combined degeneration.
The trap
Ataxia and loss of vibration sense overlap, so age, cardiomyopathy, reflex/Babinski pattern, vitamin levels, and B12 markers separate them.
The repair move
For posterior-column ataxia, pair the neurologic pattern with age, heart findings, and vitamin labs.
Try a free question
CoreAn adolescent has progressive gait ataxia, dysarthria, absent deep tendon reflexes with extensor plantar responses, impaired vibration sense, pes cavus, scoliosis, diabetes, and hypertrophic cardiomyopathy. Which diagnosis is most likely?
Show answer and explanation
Answer: A. Friedreich ataxia. Early progressive ataxia with absent reflexes plus Babinski signs, cardiomyopathy, pes cavus, and scoliosis supports Friedreich ataxia.
Why the other choices are tempting
- B. Vitamin E deficiency can mimic ataxia but lacks the classic inherited cardiomyopathy/skeletal package.
- C. Subacute combined degeneration is B12 deficiency with posterior column and corticospinal findings.
- D. MS causes relapsing CNS demyelinating lesions.
- E. Wilson disease adds liver disease, KF rings, and copper abnormalities.
Flashcards
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What cardiac clue supports Friedreich ataxia?
Hypertrophic cardiomyopathy supports Friedreich ataxia and is a major cause of mortality.
What genetic change causes Friedreich ataxia?
GAA repeat expansion in the frataxin gene causes Friedreich ataxia.
Quick answers
What is the fastest way to tell Friedreich ataxia from Vitamin E deficiency and subacute combined degeneration?
Friedreich is inherited early ataxia plus cardiomyopathy; vitamin E is deficiency mimic; B12 SCD is posterior column/lateral tract myelin disease with B12 labs.
What is the key clue for Friedreich ataxia?
Friedreich ataxia causes childhood/adolescent progressive gait ataxia, dysarthria, loss of vibration/proprioception, absent deep tendon reflexes plus extensor plantar responses, pes cavus, scoliosis, diabetes, and hypertrophic cardiomyopathy.
What is the key clue for Vitamin E deficiency and subacute combined degeneration?
Vitamin E deficiency can mimic Friedreich-like spinocerebellar/posterior column disease; subacute combined degeneration from B12 deficiency causes posterior column and lateral corticospinal tract dysfunction with macrocytic anemia or neuropathy clues.
What is the common trap with Friedreich ataxia vs Vitamin E deficiency and subacute combined degeneration?
Ataxia and loss of vibration sense overlap, so age, cardiomyopathy, reflex/Babinski pattern, vitamin levels, and B12 markers separate them.