NMJ disorders

Question 1

Epidermiology of MG?

Answer 1

Early onset-<40 F:M-4:1
Late onset->40 1:2
Overall 3:2

Question 2

Pathophysiology of MG?

Answer 2

3

Question 3

Clinical manifestations of MG?

Answer 3

6
Fatiguable muscle weakness (hallmark)
-ocular (commonest)
-limb
-bulbar
-respiratory
>50% present with ptodis and diplopia
Pupils,bladder ,bowel,heart are not affected
Nerve conduction N therefore no sensory deficit and deep tendon reflexes are normal
Usually BL but asymmetric

Question 4

Whats occular MG and whats generalized MH?

Answer 4

Occular- confined to occular muscles >2 yrs after onset , 15% of MG
Generalized- spreading to rest of thr places ,85%

Question 5

MG and thymus?

Answer 5

4

Question 6

Ix of MG?

Answer 6

1.endophonium (tensilon) test 6
2.repetitive nerve stimulation-decremented response
3.serum anti AchR ab (85% sesitive,100% specific)-sero positive,antiMUSK ab (sero -)
4.CT thorax (thymic pathology)
5.single fiber EMG (decrease response)

Question 7

Mx of MG?

Answer 7

1.symptomatic tx -
Anticholinesterase (pyridostigmine,neostigmine)
2.immunosuppressant tx
Corticosteroids (prednisolone)
Azathioprine,ciclosporin,mycophenolate
3.immunomodulatory tx
IVIg,plasma exchange,thymectomy

Question 8

Lambert eaton MG?

Answer 8

6
Mediated by voltage gated ca channel ab
Small celllung ca in 60%-paraneo
Proximal myopathic features
Warming up phenomenon (weakness improves with sustained exercise)
Tendon reflexes are absent but reappear after sustained exercises
Autonomic symptoms (dry mouth,constipation,impotence)
Milt ptosis