Mysthenia Gravis MCQ

Question 1

Myasthenia Gravis has
a) prevalence of :1000
b) predominantly a disease of young women and old man
c) Affects eye musculature in majority of patients
d) May present with respiratory failure
e) Commonly causes sensory symptoms

Question 2

Myasthenia gravis Can be diagnosed by
a) History of characteristic muscle weakness
b) The edrophonium test
c) Decrement (fade) of the compound muscle action potential titanic stimulation
d) Single fiber electromyelogram
e) Detection of anti acetylcholine antibodies

Question 3

The following is used for long-term treatment of myasthenia gravis
Adrophonium
Pyridostigmine
IV immunoglobulins
Plasma exchange
Prednisone

Question 4

Concerning the effects of drugs in myasthenia gravis
a)There is a normal response to volatile anesthetic agents
b) There is normal response to six
c) Patient with MG require 10%of dose of atracurium
d) Gentamycin may worsen MG weakness
e) Initialtion of steroids may result in respiratory muscle failere

Question 5

The following predict the need for prolonged postoperative ventilation
a) FVC< 2l
b) History of myasthenia weakness
C) COPD
d) Transcervical thymectomy
e) Grade 3 MG

Question 6

Question 1. YouareaskedtoreviewCatriona,a28-year-oldwomanwithmyastheniagravis whoislisted for cardiothoracic surgery. a) List four symptoms and two signs of myasthenia gravis. (6 marks)

Answer 6

aSymptoms: Diplopia Duetoweaknessof extraocularmuscles. •Dysphagia Due to weakness of palatal/ pharyngealmuscles.
•Dysarthria/nasalspeech •Inability to smile/close mouth/ impaired facial expression
•Difficulty
chewing
Weakness of musclesof mastication.
•Limbweakness
•Dyspnoea Signs:Any2 •Fatigableweakness •Ptosis Weakness of levator palpebrae superioris.
•External ophthalmoplegia/ strabismus (squint) Weakness of extraocular muscles.

Question 7

Question 1. YouareaskedtoreviewCatriona,a28-year-oldwomanwithmyastheniagravis whoislisted for cardiothoracic surgery
What is the surgical procedure most likely to be?

Answer 7

Thymectomy(excision of thymoma)

Question 8

What are the two common proteins targeted by autoantibodies in myasthenia gravis?

Answer 8

Nicotinic acetylcholine receptor
Muscle-specific kinase(MuSK)
Both of these are located at the neuromuscular junction.

Question 9

Which subtype of immunoglobulin is produced? (1 mark)

Answer 9

Immunoglobin-G must be IgG because autoantibodies can cross the placenta, resulting in congenital myasthenia gravis.

Question 10

List three health conditions associated with myasthenia gravis. (3 marks)

Answer 10

Autoimmunethyroiditis •Grave’sdisease •Rheumatoidarthritis •Type1 diabetes mellitus •Scleroderma
•Vitiligo •Polymyositis/dermatomyositis
•Systemiclupuserythematosus •Perniciousanaemia

Question 11

List three classes of drug that the patient might be prescribed pre-operatively to manage the symptoms of myasthenia gravis. (3 marks)

Answer 11

AnticholinesterasesE.g.pyridostigmine. Immunosuppression E.g.prednisolone, azathioprine,cyclosporine.
Intravenous immunoglobulin or plasma exchange

Question 12

Catriona is concerned about her risk of requiring post-operative ventilation. g) Describe two methods you would consider to achieve intubation following induction of general anaesthesia that could reduce this risk. (2 marks)

Answer 12

•Deep inhalational anaesthesia alone
Any2
•Reduced dose of nondepolarising muscle relaxant ~30%ofnormaldoseof atracurium,vecuroniumor rocuronium
•Increased dose of suxamethonium •Remifentanil infusion/total intravenous anesthesia

Question 13

Due to a miscommunication, the patient stops taking her medication pre-operatively and presents to the Emergency Department with features of a myasthenic crisis. h) List two such features. (2 marks)

Answer 13

•Inability to support Chin falls onto chest •Absent gag reflex:risk of aspiration of oral secretions
•Poor or absent cough Accumulation of secretions
•Respiratory distress/use of accessory muscles/paradoxical abdominal breathing/ventilatory failure