Muscle and Nerve Diseases

Question 1

What energies do muscles convert?

Answer 1

Chemical energy into mechanical energy

Question 2

What are some components required for a muscle to convert chemical energy into physical energy?

Answer 2

Structural components

Contractile mechanism

Excitation-contraction coupling (ion channels)

Energy system

Question 3

What are some symptoms of muscle disease?

Answer 3

Weakness of skeletal muscles

Shortness of breath if respiratory muscles

Poor swallow/aspiration if bulbar muscles

Cardiomyopathy

Cramp

Pain

Stiffness

Myoglobinuria

Question 4

What are signs of muscle disease?

Answer 4

Wasting/hypertrophy

Normal or reduced tone and reflexes

Motor weakness, no sensory reflex

Question 5

What investigations are done for muscle disease?

Answer 5

History and examination

Creatine kinase (CK)

EMG

Muscle biopsy (structure, biochemistry, inflammation)

Genetic testing

Question 6

What are the different categories of congenital/genetic muscle diseases?

Answer 6

Structural (muscular dystrophies)

Contractile (congenital myopathies)

Coupling (channelopathies)

Energy (enzymes/mitochrondia)

Question 7

What are the different classifications of acquired muscles diseases?

Answer 7

Metabolic (Ca, K)

Endocrine (thyroid, adrenal, vitamin D)

Inflammatory muscle disease

Iatrogenic (medication such as steroids or statins)

Question 8

Is CK often high or low in muscular dystrophies?

Answer 8

High due to cell degeneration

Question 9

What are examples of mucular dystrophies?

Answer 9

Duchenne’s/Becker’s (dystrophin)

Fascioscapulohumeral/oculopharyngeal/limb girdle

Myotonic dystrophy (cataracts)

Question 10

Are there any specific treatments for muscular dystrophies yet?

Answer 10

No

Question 11

What are channelopathies?

Answer 11

Disorders of Ca, Na, K and Cl channels

Question 12

What are common symptoms of channelopathies?

Answer 12

Paroxysmal symptoms such as periodic paralysis/myotonia

Question 13

What is myotonia?

Answer 13

Inability to relax voluntary muscles after vigorous effort

Question 14

What are energy production muscle disorders also known as?

Answer 14

Metabolic myopathy

Question 15

What is are metabolic myopathy disorders induced by?

Answer 15

Exercise induced

Early are disorders of carbohydrate metabolism

Late are disorders of lipid metabolism

Mitochondrial problems

Question 16

What are inflammatory muscle diseases also called?

Answer 16

Inflammatory myopathies

Question 17

What are examples of inflammatory myopathies?

Answer 17

Polymyositis

Dermatomyositis (DM)

Question 18

What is the clinical presentation of inflammatory myopathies?

Answer 18

Painful, weak muscles

Characteristic rash of DM

Question 19

What is seen in blood tests for inflammatory myopathies?

Answer 19

High CK

Autoantibodies

Question 20

What investigations are done for inflammatory myopathies?

Answer 20

EMG

Biopsy

Question 21

How does the biopsy for polymyositis and dermatomyositis differ?

Answer 21

Polymyositis shows CD8 cells

Dermatomyositis shows humeral-mediated, B cells and and CD4 cells

Question 22

What is the treatment for inflammatory myopathies?

Answer 22

Immunosuppression

Question 23

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

Answer 23

Myasthenia gravis

Question 24

What is the clinical presentation of myasthenia gravis?

Answer 24

Fatiguable weakness:

Ptosis

Diplopia

Limb weakness

Bulbar weakness (chew, swallow, talk)

Breathing weakness

Question 25

What investigations are done for myasthenia gravis?

Answer 25

Blood test (AChR, anti MuSK antibodies) Neurophysiology (repetative stimulation, jitter) CT chest (thymoma)

Question 26

What is the treatment for myasthenia gravis?

Answer 26

Symptomatic treatment - acetycholinesterase inhibitory (pyridostigmine) Immunosuppresion - prednisolone, steroid saving agent (such as azathioprine) Thymectomy (operation to remove thymus)

Question 27

What is the operation to remove the thymus called?

Answer 27

Thymectomy

Question 28

What does the term "peripheral nerves" consist of?

Answer 28

Sensory axons (small fibre (pain and temperature) and large fibre (joint position sense and vibration)) Motor axons Autonomic axons Nerve sheath (myelin)

Question 29

What are examples of diseases of peripheral nerves?

Answer 29

Root disease Lesion of individual peripheral nerve Generalised peripheral neuropathy

Question 30

What is the clinical presentation of root disease?

Answer 30

Myotomal wasting and weakness Reflex change Dermatomal sensory change

Question 31

What do lesions of individual peripheral nerves cause?

Answer 31

Compressive/entraopment neuropathy Vasculitis

Question 32

What is the clinical presentation of lesions of individual peripheral nerves?

Answer 32

Wasting and weakness of innervated muscle Specific sensory change

Question 33

What are the 2 different kinds of peripheral neuropathy?

Answer 33

Axonal loss or demyelination

Question 34

What are some causes of peripheral neuropathy?

Answer 34

Genetic Metabolic (diabetes, alcohol, renal failure, B12) Toxic (drugs) Infectious (lyme, HIV, leprosy) Malignancy (demyelinating) Inflammatory demyelinating (acute is Guillain Barre syndrome, chronic is chronic inflammatory demyelinating polyneuropathy)

Question 35

What is acute peripheral neuropathy due to inflammation called?

Answer 35

Guillain Barre syndrome

Question 36

What is chronic peripheral neuropathy due to inflammation called?

Answer 36

Inflammatory demyelinating polyneuropathy

Question 37

What is the clinical presentation of peripheral neuropathy?

Answer 37

Sensory and motor symptoms Usuallt starting distally and moving proximally

Question 38

What investigations are done for nerve disease?

Answer 38

Blood tests Genetic analysis Nerve conduction studies Lumbar puncture (CSF analysis) Nerve biopsy

Question 39

What is the general treatment for nerve diseases?

Answer 39

Treat the cause (such as stop drug, surgery, immunoglob)

Question 40

What is an example of a disorder of anterior horn cell?

Answer 40

Motor neuron disease (MND)

Question 41

What does MND stand for?

Answer 41

Motor neuron disease

Question 42

What is motor neuron disease also known as?

Answer 42

Amyotrophic lateral sclerosis (ALS)

Question 43

What does ALS stand for?

Answer 43

Amyotrophic lateral sclerosis

Question 44

What does MND usually first affect?

Answer 44

Limb, then bulbar muscles, then respiratory

Question 45

Does MND show UMN or LMN signs?

Answer 45

Combination of both UMN and LMN signs

Question 46

What are some LMN signs of MND?

Answer 46

Muscle fasciculations, wasting and weakness

Question 47

What are some UMN signs of MND?

Answer 47

Increased tone, brisk reflexes

Question 48

Does motor neuron disease have any sensory involvement?

Answer 48

No sensory involvement

Question 49

Other than physical symptoms, what else can MND cause?

Answer 49

10% have cognitive decline

Question 50

What is the prognosis of MND?

Answer 50

Median 3-5 years from symptom onset, 2-3 years from diagnosis 50% die within 14 months of diagnosis

Question 51

How is MND diagnosied?

Answer 51

Unique combination of UMN and LMN signs with no sensory signs EMG

Question 52

What is the treatment for MND?

Answer 52

Supportive (PEG feed, non-invasive ventilation, physio, OT, SALT, care) Riluzole Anticipatory/palliative care