Muscle and neuromuscular junction

Question 1

What kind of motor neurone disorders (lower or upper) present with weakness, low tone and fasiculations?

Answer 1

Lower motor neurone disorders

Question 2

What neurotramsmitter is released across the neuromuscular junction?

Answer 2

Acetylcholine

Question 3

What enzyme breaks down acteylcholine?

Answer 3

Acetylcholinesterase

Question 4

What toxin affects the presynaptic terminal of the neuromuscular junction?

Answer 4

Botulism - Clostridium botulinum

Question 5

What toxin causes rapid onset weakness but with no sensory loss?

Answer 5

Botulism toxin

Question 6

What is lambert eaton myasthenic syndrome?

Answer 6

Antibodies form to presynaptic calcium channels and lead to less vesicle release.

Question 7

What underlying condition is lamber eaton myasethenic syndrome associated with?

Answer 7

Small cell carcinoma

Question 8

What condition affects the post synaptic terminal of the neuromuscular junction?

Answer 8

Myasthenia Gravis

Question 9

In what condition do you get antibodies to ACh receptors?

Answer 9

Myasthenia gravis

Question 10

A man presents with muscle weakness in his face and find his eyes drooping at the end of the day.

Answer 10

Myaesthenia gravis

Question 11

How do the antibodies in myasthenia gravis cause problems?

Answer 11

• Block binding of ACh

- Trigger inflammatory cascade that damages the folds of the postsynaptic membrane

Question 12

What other structure has a role in myaesthenia gravis?

Answer 12

Thymus. 75% of patients with MG have hyperplasia or thymoma

Question 13

What is the drug treatment of choice in myaesthenia gravis?

Answer 13

Acetylcholinesterase inhibitor - pyridostigmine

Question 14

What surgical treatment is sometimes required in myasethenia gravis?

Answer 14

Thymectomy

Question 15

What is a fascilation?

Answer 15

A visible fast fine spontaneous twitch

Question 16

Is a fasciculation usually a sign of disease in the motor neurone or the muscle itself?

Answer 16

Motor neurone

Question 17

What kind of muscle do fasciculations occur in?

Answer 17

Denervated muscle which becomes overexcitable

Question 18

What is myotonia?

Answer 18

The failure of muscle relaxation after use

Question 19

Where is the problem is myotonia?

Answer 19

Chloride channel

Question 20

Name two imflammatory muscle disease?

Answer 20

Dermatomyositis

Polymyositis

Question 21

A 54 year old lady comes in complaining of weakness in her things and arms over the last 2 months. Her blood tests show a raised CK

Answer 21

Polymyositis

Question 22

What is the first line treatment for someone with raised CK?

Answer 22

Steroids

Question 23

A 54 year old lady comes in complaining of weakness in her things and arms over the last 2 months. On examination she has a rash across her face.

Answer 23

Dermatomyositis

Question 24

What can dermatomyositis be a sign of?

Answer 24

An underlying malignancy

Question 25

A 75 year old man comes in complaining of muscle weakness in all his muscles apart from his thumb. He says this has been coming on slowly for about 2 years.

Answer 25

Inclusion body myositis

Question 26

What is the inheritance pattern on myotonic dystrophy?

Answer 26

Autosomal dominant

Question 27

A 49 year old women presents with muscle weakness and wasting. She also reports a clouding of her vision and frontal balding. Her mum also had similar symptoms before her death.

Answer 27

Myotonic dystrophy