Charcot Marie Tooth Flashcards
What is Charcot Marie Tooth?
AKA Hereditary motor + sensory peripheral neuropathy
Not a single disease but a group of hereditary diseases of the PNS
- Inherited
- Neuropathy is the sole/ primary component
- Worsens over time
- Sensory + motor affected
Case hx of a patient with Charcot Marie Tooth
45 year old man, presenting with bilateral stepping gait, foot numbness and difficulty with buttons.
Toe-walker from 13 months, unable to ice-skate as ankles weak. Began tripping and falling monthlly in 20s
Problems with hands started 5 years ago
Charcot Marie Tooth epidemiology
1 in 2500 people
Most common forms of Charcot Marie Tooth
CMT1 and CMT2
Discuss Charcot Marie Tooth type 1
CMT1 affects the Schwann (rhymes)
CMT1 is the most common form (50% cases)
- Onset by 10yrs
- Mutation affected Schwann cells and myelin
- Muscle wasting in small muscles of hands + feet
- Spreads to legs and arms
- Foot drop, pes cavus
Discuss Charcot Marie Tooth type 2
CMT2 affects axons
- Onset in 2nd decade
- Similar patterns of weakness in CMT1
What is the overriding pathophysiology in Charcot Marie Tooth?
Hereditary diseases that cause defective production of proteins in the myelin shealth or neuronal axon
Presentation of Charcot Marie Tooth
Muscular atrophy as motor nerves affected: weakness, foot drop, high-stepping gait
Walking difficulty
Pes cavus
Hyporeflexia
Reduced sensation
Toe walking
Which muscles commonly atrophy in Charcot Marie Tooth?
Intrinsic muscles of hands and feet
Foot deformities common in Charcot Marie Tooth
Hammer toes, toe walking, pes cavus, high stepping gait, foot drop, muscle atrophy
Charcot Marie Tooth investigations
Nerve conduction: slowed conduction velocity
Genetic testing: mutations associated with specific CMT subtype
Nerve biopsy: repeated demyelination + remyelination (onion peel)
Management of Charcot Marie Tooth
Physio + exercise
Bracing
Surgery for feet e.g. hammer toe straightening
Prongosis of Charcot Marie Tooth
CMT1 = normal life expectancy
Other subtypes associated with reduced life expectancy
