Disorders of Muscle

Question 1

What is an example of a neuromuscular junction disorder of muscle?

Answer 1

Myasthenia Gravis

Question 2

What is Myasthenia Gravis?

Answer 2

Autoimmune destruction of end plate ACh receptors
Loss of junctional folds at end plate
Widening of the synaptic cleft

Question 3

What characterisies Myasthenia Gravis?

Answer 3

Muscle weakness
Drooping eyelids
No sensory loss
Some atrophy

Question 4

What is the treatment for Myasthenia Gravis?

Answer 4

Acetylcholinesterase inhibitors

Question 5

What environmental factors can effect neuromuscular transition

Answer 5

Botulism (Toxins block Ach release)
Organophosphate poisoning (Inhibit acetylcholinesterase irreversibly)

Question 6

What is Muscular Dystrophies?

Answer 6

Genetic disorders that produce progressive muscle weakness and wasting. There is Pseudohypertrophy followed by atrophy and muscle fibre replacement with fat and connective tissue.

Question 7

What is the muscle fibre damage in Duchenne’s Muscular Dystrophy?

Answer 7

There is a protein abnormality so muscle fibres tear themselves on contraction. Creatine kinase released into serum and calcium enters, causes necrosis. Followed by pseudohypertrophy and fat/connective tissue replacement

Question 8

What is the defect in Duchenne Muscular dystrophy?

Answer 8

Inherited single gene defect on X chromosome

Question 9

What is Gower’s sign?

Answer 9

Seen in children who are developing Duchennes Muscular Dystrophy. Defined as postural problems

Question 10

How can you treat Duchenne Muscular Dystrophy?

Answer 10

Steroid therapy and genetic research