Nerve, muscle and NMJ pathology Flashcards
What is the cause of Lambert eaton syndrome?
autoimmune often have underlying malignancy
What is the cause of myasthenia gravis
autoimmune
What is the cause of Duchennes muscular dystrophy?
Genetic
What is a paraneoplastic syndrome?
confusing, diverse range of conditions caused by malignant tumours (caused by different substances tumours secrete)
What is motor neurone disease?
- progressive degeneration of upper and lower motor neurone
- unknown cause
What are the symptoms?
- difficulty moving limbs + weakness
- speaking
- swallowing
- breathing
What is the cause of motor neurone disease?
idiopathic
What nerves are usually affected in MND?
both upper and lower motor neurones
What part of the NMJ does Lambert eaton affect?
Ca2+ channels on the motorneurone
- autoantibodies against the calcium channels
What are the symptoms of Eaton Lambert syndrome?
- muscle weakness
- hyporeflexia
- arefelxia
- autonomic dysfunction
What is the most common cancer causing Lambert eaton?
lung cancer (specifically small cell carcinoma)
What autoantibody is present in myasthenia gravis?
autoantibodies for Ach receptors
Why is thymus relevant to MG?
removal of thymus gland as can be hyper plastic in MG, can reduce symptoms (due to involvement with T cell maturation)
What organ is often enlarged n MG?
hyperplasia of thymus
What tests should be done to diagnose polymiositis?
- muscle biopsy
- blood test for autoantibodies
- lots of different autoantibodies can be present
What are the symptoms of polymiositis?
- chronic muscle inflammation
- chronic muscle weakness
What histology would support rheumatoid arthritis?
lymphocytic infiltration
How is Duchennes muscular dystrophy inherited?
X-chromosome linked
What protein is involved in Duchennes muscular dystrophy?
dystrophin which is an important cell membrane protein in muscle cells
What histological findings would be seen in Duchennes muscular dystrophy?
by endstage fatty infiltration
Why is Duchennes muscular dystrophy described as causing pseudo hypertrophy?
muscle is enlarged but due to fatty infiltration not muscle atrophy
Why is Duchennes muscular dystrophy described as causing pseudo hypertrophy?
muscle is enlarged but due to fatty infiltration rather than muscle growth
What are the symptoms of MG?
- non-constant muscle weakness
- often affects eyes and face first
- triggered by stress, infections and medication
- droopy eyelids, double vision
What are the symptoms of Duchennes muscular dystrophy?
- enlarged calf muscles
- delayed motor development
- muscle weakness progressive
- waddling gait
- cardiomyopathy
