Neuromuscular Disease: inherited and acquired

Question 1

What components do we look at when examining for neuromuscular disorders?

Answer 1

• Tone (spastic, flaccid)
• Power
• Coordination (symmetrical?)
• Reflexes
• Sensation

Question 2

What is a patient’s strength and reflexes like in muscle disorders (myopathy)?

Answer 2

• Weakness: usually proximal
• Weakness > wasting
• Reflexes normal (except in severely wasted muscle)
• Sensory: normal

Question 3

Muscular dystrophies are mostly genetic. Name examples of muscular dystrophies

Answer 3

• Duchenne
• Becker
• Myotonic
• Facioscapulohumoral

Question 4

Duchenne muscular dystrophy is one of the most common dystrophies, what gene is affected?

Answer 4

Xp21 - dystrophin gene

Question 5

What is the age of onset for Duchenne muscular dystrophy?

Answer 5

3-5

Death usually in 20s

Question 6

What are problems of Duchenne muscular dystrophy?

Answer 6

• proximal weakness
• scoliosis, resp failure, cardiomyopathy

Question 7

In Duchenne’s, why might a child’s calf look bigger than it is?

Answer 7

Infiltration of fat and connective tissue (not muscle)

Question 8

What happens if we don’t have the distrophin molecule?

Answer 8

Compromise the muscle membrane integrity, results in weakness and atrophy of muscles.

Question 9

What is the difference between Duchenne and Becker muscular dystrophies?

Answer 9

• Duchenne - frameshift deletion leads to non-functional protein
• Becker - non-frameshift deletion leads to reduced function protein

Symptoms for Becker are therefore less severe

Question 10

Myopathies can either be genetic or acquired. Dystrophies are genetic, which pathologies are acquired?

Answer 10

• Inflammatory myopathies
• > polymyositis, dermatomyositis, inclusion body myositis
• Endocrine, GI, paraneoplastic, renal, toxic, infections, iatrogenic (steroids)

Question 11

Name an inherited neuromuscular junction disorder?

Answer 11

Congenital myasthenic syndromes

Question 12

Is myasthenia gravis acquired or inherited?

Answer 12

Acquired

Question 13

What are reflexes and sensory function like in neuromuscular junction diseases?

Answer 13

Normal

Question 14

What are the most common causes of neuropathies?

Answer 14

• Axonal neuropathies (80%)
• Demyelinating neuropathies (20%)

Question 15

Mononeuropathy disorders affect only one nerve. What nerve is compressed in carpal tunnel syndrome?

Answer 15

Median nerve

Question 16

Compressing on the elbow or wrist can entrap which nerve? Also linked to handlebar neuropathy

Answer 16

Ulnar nerve

Question 17

Which compressed nerve is responsible for foot drop?

Answer 17

Common peroneal nerve

Question 18

What is the most common cause for metabolic polyneuropathy?

Answer 18

Diabetes, also renal failure as well as B12 def.

Question 19

What are characteristics of Charcot-Marie-Tooth disease?

Answer 19

• Hereditary polyneuropathy
• Common genetic neurological disorder
• 1/2500 prevalence
• Majority autosomal dominant
• 60% have CMT1A

Question 20

What is the presentation of Charcot-Marie-Tooth disease?

Answer 20

• Slowly progressive distal symmetrical sensorimotor polyneuropathy
• Distal wasting prominent
• Pes cavus

Question 21

What is the orientation of the arm in Erb’s Palsy?

Answer 21

C5, C6 nerve roots damaged

• Arm adducted
• Elbow extended
• Wrist pronated + flexed

Question 22

What happens in radiculopathy?

Answer 22

Nerve root is affected -> radicular (nerve root pain) and weakness, wasting

Question 23

What are common causes of radiculopathy?

Answer 23

Arthritis + prolapsed disc

Question 24

What happens in motor neurone disease?

Answer 24

• Primary degeneration of motor neurones in central AND peripheral NS
• Genetic or acquired
• Affects lower and upper motor neurones
• Affects control of all voluntary muscles except ocular + bladder
• Fatal within 5 years of diagnosis