Neuromuscular Disorders

Question 1

How do lower motor neuron disorder present?

Answer 1

• Weak, wasted muscle
• Low tone
• Fasciculations
• Reduced or absent reflexes

Question 2

What drugs should be avoided in myasthenia gravis?

Answer 2

Gentamicin

Question 3

What drug is used for symptomatic treatment of myasthenia gravis?

Answer 3

Pyridostigmine

Question 4

What is long-term management of myasthenia gravis?

Answer 4

Immunosuppression
- Steroids
- Azathioprine/mycophenolate (elderly especially)

Question 5

Are ACh receptors inotropic or metabotropic?

Answer 5

Inotropic

Question 6

What is the motor end plate?

Answer 6

The junction between motor neuron and muscle

Question 7

Are pre-synaptic or post-synaptic neuromuscular disorders more common?

Answer 7

Post-synaptic

Question 8

What organism causes botulism?

Answer 8

Clostridium botulinum

Question 9

Who is at high risk of botulism?

Answer 9

IV drug users

Question 10

What is the early signs of botulism?

Answer 10

Extra-ocular paralysis

Question 11

What causes myasthenia gravis?

Answer 11

Antibodies to acetylcholine receptors

Question 12

When do symptoms begin in myasthenia gravis?

Answer 12

When ACh receptors reduced to 30% of normal

Question 13

There is a spike in myasthenia gravis in men and women at what ages?

Answer 13

Women in 20’s
Men in 50’-60’s

Question 14

What are typical clinical features of myasthenia gravis?

Answer 14

• Fluctuating weakness
• Extraocular weakness, Facial & bulbar weakness
• Limb weakness (typically proximal)
• Fatiguability

Question 15

What diagnostic tests are used in myasthenia gravis?

Answer 15

• Test for ACh antibodies (present in 80-90% of cases)
• EMG studies to find patterns to distinguish MG from LEMS
• CT for thyoma

Question 16

What is the likelihood that there is thymus involvement in MG?

Answer 16

75% present with hyperplasia or thyoma

Question 17

What is myotonia?

Answer 17

Failure of muscle relaxation after use

Question 18

What causes myotnia?

Answer 18

Cl- channel disorder

Question 19

How will a patients creatine kinase (CK) read if they have a muscle disease?

Answer 19

Raised CK

Question 20

What are the three divisions of neuromuscular disease?

Answer 20

• Immune mediated
• Inherited
• Congenital

Question 21

Name some immune mediated neuromuscular diseases?

Answer 21

• Dermatomyositis
• Polymyositis

Question 22

What is the most common muscular dystrophy?

Answer 22

Myotonic dystrophy

Question 23

Name some inherited neuromuscular diseases?

Answer 23

• Muscular dystrophies
• Myotonic dystrophy
• Limb girdle muscular dystrophies

Question 24

What is the inheritance pattern of myotonic dystrophy?

Answer 24

Autosomal dominant

Question 25

What is rhabdomyolysis?

Answer 25

Damage to skeletal muscle causing leakage of large quantities of toxic intracellular contents into plasma

Question 26

How does rhabdomyolysis present?

Answer 26

Myalgia, muscle weakness & Myoglobinuria
Incredibly high CK

Question 27

Name some pre-synaptic disorders

Answer 27

• Botulism
• Lambert Eaton Myasthenic Syndrome (LEMS)

Question 28

What is LEMS strongly associated with?

Answer 28

Small cell carcinoma

Question 29

How is LEMS treated?

Answer 29

3-4 Diaminopyridine