Congenital or genetic neurological disorders Flashcards
What is a type 1 Chiari malformation?
Cerebellar tonsils lie below the foramen magnum - cerebellar ectopia
May or may not be Sx
What is the name given to a condition where the cerebellar tonsils congenitally sit below the foramen magnum (cerebellar ectopia)?
Type 1 Chiari malformation
What is a type 2 Chiari malformation?
Part of the cerebellar vermis, medulla and 4th ventricle extend through the foramen magnum often down to mid cervical region
How does a type 2 Chiari often present?
Syringomyelia/hydromyelia
Spina bifida
Hydrocephalus
CN signs as lower CNs are stretched
What is Klippel Feil?
Association between cervical fusion and type 2 Chiari malformation
What is the name given to a condition where part of the cerebellar vermis, medulla and 4th ventricle extend down through the foramen magnum congenitally?
Type 2 Chiari malformation
What is a type 3 Chiari malformation?
Part of the cerebellum and medulla lie within a cervico-occipital meningomyelocoele
What is the name given to a condition where part of the cerebellum and medulla lie within a meningomyelocoele?
Type 3 Chiari malformation
How might a Chiari malformation present in childhood?
Gait ataxia and syringomyelia
How do severe type 2/3 Chiari malformations often present?
Respiratory difficulties Lower CN palsies Spina bifida Nystagmus, retrocolis and spasticity In infancy
How can mild type 2 or type 1 chiari malformations present?
In adulthood with spastic quadraplegia, ataxia, occipital pressure dependent headaches and nystagmus
As well as severe bulbar Sx
What form do lower limbs take in CMT?
Inverted champagne bottles due to distal muscle wasting
What is the classical picture of CMT1a?
LMNL of intrinsic foot muscles, peroneal and tibial groups and distal UL involvement, often with palpable peripheral nerves
Pes cavus common
Ataxia and tremor can occur
When does CMT1a present?
Usually before 30
What form do lower limbs take in CMT?
Inverted champagne bottles due to distal muscle wasting
What is the classical picture of CMT1a?
LMNL of intrinsic foot muscles, peroneal and tibial groups and distal UL involvement, often with palpable peripheral nerves
Pes cavus common
Ataxia and tremor can occur
When does CMT1a present?
Usually before 30
What form do lower limbs take in CMT?
Inverted champagne bottles due to distal muscle wasting
What is the classical picture of CMT1a?
LMNL of intrinsic foot muscles, peroneal and tibial groups and distal UL involvement, often with palpable peripheral nerves
Pes cavus common (high foot arches)
Ataxia and tremor can occur
When does CMT1a present?
Usually before 30, often in childhood or early adulthood
What is the common presenting feature of CMT?
Foot drop, which may be unilateral
What sensory modalities tend to be affected in CMT? What isn’t?
Dorsal columns - touch, vibration, proprioception
Pain isn’t affected so neuropathic pain can be a feature
What toe changes are seen in CMT?
Claw toes and hammer toes
What is the prevalence of CMT?
Roughly 1/2500
What protein is dysfunctional in CMT1A?
PMP-22 (peripheral myelin protein 22)
What 2 diseases are characterised by dysfunctional PMP-22 protein?
CMT1A
HNPP
What is the affected protein in CMT1B?
Myelin protein zero (P0)
What disease is characterised by myelin protein zero (P0) dysfunction?
CMT 1B
What type of neuropathy does CMT 1 produce and what does this show on neurophysiology?
Demyelinating - reduced conduction velocity
How are CMT 1 and 2 inherited?
AD