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Flashcards in Nerve and Muscle Disease Deck (47)
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1
Q

McArdle’s disease is autosomal recessive - T/F?

A

TRUE

2
Q

pathophysiology behind McArdle’s disease

A

myophosphorylase deficiency leading to impaired glucose release from glycogen in the muscles

3
Q

how does McArdle’s disease present?

A

1st decade of life

pt presents with muscle pain shortly after they exercise

4
Q

CK is decrease in McArdle’s disease - T/F?

A

FALSE

5
Q

why must pt stop vigorous exercising when they get pains?

A

it could lead to rhabdomyolysis + myoglobinuria = AKI

6
Q

What is myotonic dystrophy?

A

Multisystem progressive disease with delayed muscular relaxation and muscle wasting

7
Q

What is the inheritance of myotonic dystrophy?

A

Autosomal dominant

Tri nucleotide repeat on chromosome 19

8
Q

Clinical features of myotonic dystrophy

A

Sternocleidomastoid muscle + Distal limb affected 1st
Proximal limb affected later

Facial weakness (‘haggard’’ appearance

Ptosis, ophthalmoplegia & bilateral Christmas tree-like cataracts

Hollowing of temples due to temporalis muscle wasting & atrophy of jaws

Early frontal balding

9
Q

Lambert-Eaton myasthenic syndrome pathophysiology

A

Impaired release of acetylcholine by the pre-synaptic terminal

10
Q

what voltage gated channels does Lambert-Eaton syndrome affect?

A

Ca2+

11
Q

what malignancy is lambert-eaton syndrome associated with?

A

Small cell lung cancer

12
Q

clinical features of lambert-eaton syndrome

A

insidious onset of weakness of PROXIMAL muscles
Autonomic features - constipation, postural hypotension, dry mouth
Deep tendon reflexes diminished

13
Q

the upper extremities are most affected in L-E syndrome - T/F?

A

FASLE.

Lower extremities are predominantly affected - this causes a waddling gait

14
Q

Ix L-E syndrome

A

presence of anti -VGCC antibodies

repetitive electrical stimulation at 20-50Hz

CT scan to rule out malignancy (SCC)

15
Q

Tx L-E syndrome

MOA of drug

A

Amifampridine

Blocks pre-synaptic Ca2+ channels & increases quantity of ACh released

16
Q

If L-E is very severe, what medication may be used?

A

Immunosuppression or IV immunoglobulins

17
Q

What is myasthenia gravis (MG) ?

A

autoimmune disease affecting post-synaptic nicotinic acetylcholine receptors

18
Q

who does MG affect?

A

F>M

10-30 y/o

19
Q

clinical features of MG?

A

muscle fatigability occurring quickly after exercise or end of day. improves with rest

ocular features can be presenting complaint - bilateral asymmetrical ptosis & extraocular weakness causing diplopia

Proximal muscle weakness > Distal

20
Q

one complication of MG is Myasthenia crisis - what is this?

A

weakness of respiratory muscles causing ventilator failure

bronchopneurmonia - medications can precipitate this

21
Q

how to monitor the respiratory complications of MG?

A

measure vital cap & tidal volume

22
Q

at what stage do you need an intervention for the respiratory complications of MG?

A

when vital capacity falls below 15mL/kg

23
Q

what tx do you give to pt when their vital capacity falls below 15mL/kg

A

plasmapheresis
IV immunoglobulins
systemic steroids

24
Q

what is cholinergic crisis

A

too much anticholinesterase given

symptoms = sweating, hypersalivation, bronchial hypersecretions & miosis - can lead to resp failure

25
Q

what conditions are associated with myasthenia gravis?

A

thymic hyperplasia
thyoma
hyperthyroidism
SLE

26
Q

drugs that can induce MG

A
gentamicin 
b-blockers
verapamil
lithium 
penicillamine 
phenytoin 
chloroquine
27
Q

Ix MG

A

antibody test - IgG against ACh receptor (anti-AChR)
NOTE - in some pt this is -ve so they should be checked for anti-MuSK antibodies

Repetitive nerve stimulation

Thyroid function test

CT thymus

28
Q

Mx of MG

A

symptomatic control - acetylcholinesterase inhibition using pyridostigmine

Immunosuppression with corticosteroid & azathioprine to improve myasthenic weakness

Thymectomy if thyoma is present

29
Q

Is Charcot Marie tooth (type 1) autosomal dominant - T/F?

A

TRUE

30
Q

What is Charcot Marie Tooth Disease (CMT)

A

A group of diseases affecting the peripheral nerves

31
Q

Histopathology of Charcot Marie Tooth Disease

A

Schwann cells proliferate and form concentric arrays of remyelination around the demyelinated axon resulting in ‘onion bulb’ appearance

32
Q

When does CMT present

A

1st or 2nd decade of life

33
Q

Clinical features of CMT

A

Motor symptoms affecting distal muscles - ‘inverted champagne bottle’ appearance

Sensory loss follows same pattern

Hyporeflexia

Thoracic scoliosis

34
Q

Diagnosis of CMT

A

Genetic testing

Electrophysiological nerve conduction study (low conduction rate <38 m/s)

35
Q

What is Guillian-Barre Syndrome

A

Acute neuromuscular weakness causing demyelination and axonal injury

36
Q

What often precedes GB syndrome?

A

Campylobacter

also EBV, CMV, HIV

37
Q

Presentation of GB Syndrome?

A

Symmetrical progressive ascending sensorimotor paralysis
Areflexia in lower limbs
Usually stops progressing after 4 weeks from its onset

38
Q

Diagnosis of GB syndrome

A

Clinical

Lumbar puncture - high protein

Nerve conduction studies

39
Q

Mx of GB syndrome

A

Plasma exchange of IV immunoglobulins

40
Q

What is chronic inflammatory demyelinating polyradiculoneuropathy (CIDP)?

A

Acquired demyelinating peripheral nervous system disease

Progressive proximal & distal weakness with hyporeflexia

Distal sensory loss (numbness)

Tremor

41
Q

Diagnosis of CIDP

A

Clinical
Nerve conduction studies
CSF - high protein

42
Q

Treatment of CIDP

A

Oral steroids or IV Immunoglobulins

43
Q

What is spinal muscular atrophy

A

congenital degeneration of anterior horns of spinal cord (LMN lesion)

leads to progressive muscular wasting & early death

‘floppy baby syndrome’ - hypotonia and tongue fasciculations

44
Q

is spinal muscular atrophy X-linked recessive?

A

NO - it is autosomal recessive

45
Q

what is poliomyelitis?

A

caused by polio virus

infections causes destruction of cells in anterior horn of spinal cord (LMN death)

46
Q

how is the polio virus transmitted?

A

faecal-oral transmission

47
Q

symptoms of poliomyelitis

A
LMN signs basically:
weakness
hypotonia
flaccid paralysis 
fasciculations 
hyporeflexia 
muscle atrophy