Lecture 19 Muscle and Nerve Disease

Question 1

Symptoms of muscle disease

Answer 1

• Weakness of skeletal muscle
– Short of breath (respiratory muscles)
– Poor swallow / aspiration (bulbar muscles)
• Cardiomyopathy
• Cramp, pain, stiffness, myoglobinuria
(Babies: poor suck / feeding / failure to thrive / floppy)

Question 2

Signs of muscle disease

Answer 2

• Wasting / hypertrophy
• Normal or reduced tone and reflexes
• Motor weakness…NOT sensory

Question 3

Muscle Disease Investigation

Answer 3

•	History and examination
•	Creatine Kinase (CK)
•	EMG- Electromyography (EMG) 
Muscle bx
Genetic Testing

Question 4

What are the groups of muscle disease classification

Answer 4

Congenital/genetic

Acquired

Question 5

Name Congenital/Genetic muscle diseases

Answer 5

Muscular dystrophies
Congenital Myopathies
Channelopathis
Enzyme/mitochondira

Question 6

Name Acquired Muscle Diseases

Answer 6

– Metabolic (Ca2+, K+)
– Endocrine (thyroid, adrenal, vit D)
– Inflammatory muscle disease
– Iatrogenic: medication (steroids / statins)

Question 7

Describe Channelopathies

Answer 7

• disorders of Ca2+, Na+, K+ and Cl- channels
• often paroxysmal symptoms e.g. periodic paralysis / myotonia
• partially treatable

Question 8

Early exercise induced metabolic myopathy

Answer 8

Disorders of carbohydrate metabolism

Mitochondrial problems- partially treatable

Question 9

Late exercise induced metabolic myopathy

Answer 9

Disorders of lipid metabolism

Mitochondrial problems- partially treatable

Question 10

Name 2 inflammatory muscle diseases

Answer 10

Polymyositis

Dermatomyositis

Question 11

What are the symptoms of Inflammatory muscle disease

Answer 11

• Acute or subacute, painful, weak muscles

* Characteristic rash of DM

Question 12

Investigations for inflammatory muscle disease

Answer 12

• High CK, autoantibodies, tumour screen (esp DM)
• EMG & biopsy
– Polymyositis: CD8 cells
– Dermato: humeral-mediated, B cells and CD4 cells

Question 13

Whats the treatment to inflammatory muscle disease

Answer 13

Immunosuppression

Question 14

What is Myasthenia Gravis

Answer 14

Disorder of neuromuscular junction

Question 15

Clinical presentation of Myasthenia Gravis

Answer 15

Fatiguable weakness
Ptosis
Diplopia
Bulba (chew, swallow, talk)
Breathinh

Question 16

Investigations for disorders of the neuromuscular junction

Answer 16

• AChR, Anti MuSK antibodies
• Neurophysiology (Repetitive stimulation, Jitter)
• CT chest (thymoma)

Question 17

Treatment of Myasthenia Gravis

Answer 17

• Symptomatic
– Acetylcholinesterase inhibitor (pyridostigmine)
• Immunosuppression
– Prednisolone
– Steroid saving agent (e.g. azathioprine)
• Immunoglobulin / plasma exchange
• Thymectomy

Question 18

What does the peripheral nerve consist of

Answer 18

•	Sensory axons
–	Small fibres (pain + temperature)
–	Large fibres (joint position sense + vibration)
•	Motor axons
•	Autonomic axons
•	Nerve sheath (myelin)

Question 19

Causes of generalised peripheral neuropathy

Answer 19

–	Hereditary
–	Metabolic: diabetes, alcohol, renal failure, B12
–	Toxic: drugs
–	Infectious: Lyme, HIV, leprosy
–	Malignancy: paraneoplastic
–	Inflammatory demyelinating:
Acute = Guillain Barre syndrome
Chronic = chronic inflammatory demyelinating polyneuropathy

Question 20

Nerve root disease symptoms

Answer 20

– Myotomal wasting and weakness
– Reflex change
– Dermatomal sensory change

Question 21

Individual nerve disease symptoms

Answer 21

– Wasting and weakness of innervated muscle

– Specific sensory change

Question 22

Symptoms of generalised neuropathy

Answer 22

– Sensory and motor symptoms, usually starting distally and moving proximally

Question 23

Investigations of Nerve disease

Answer 23

• Blood tests
• Genetic analysis
• Nerve Conduction Studies
• Lumbar puncture (CSF analysis)
• Nerve biopsy (nb sensory nerve)

Question 24

Treatment of nerve problem

Answer 24

• Treat the cause eg stop drug, surgery, immunoglob

Question 25

Diagnosis of Motor Neuron Disease

Answer 25

• Unique combination of UMN + LMN signs with no sensory signs
• EMG

Question 26

Treatment of Motor Neuron Disease

Answer 26

• Supportive
– PEG feed, non invasive ventilation, physio, OT, SALT, care
• Riluzole
• Anticipatory / palliative care