Approach To Myopathy

Question 1

What is the differential diagnosis of bulbar weakness (muscular and neuromuscular etiologies)?

Answer 1

-Myasthenia gravis
-Lambert-Eaton myasthenia syndrome
-Oculopharyngeal dystrophy
-Limb-girdle muscular dystrophy type 1A
-Myotonic dystrophy
-Inclusion-body myositis

Question 2

What is the differential diagnosis of ptosis with ophthalmoplegia but without diplopia?

Answer 2

-Oculopharyngeal dystrophy
-Mitochondrial myopathy
-Centronuclear myopathy

Question 3

List 5 drugs, medications, or toxins that cause toxic NMJ disorders.

Answer 3

-Botulinum toxin
-Snake venom
-Organophosphates
-Curare
-Magnesium (hypermagnesemia)

Question 4

List medications or drugs that cause an inflammatory myopathy.

Answer 4

-Cimetidine
-D-penicillamine
-Procainamide
-L-tryptophan
-L-DOPA

Question 5

List medications or drugs that can cause a non-inflammatory myopathy.

Answer 5

-Cholesterol lowering agents
-Chloroquine
-Colchicine
-E-aminocaproic acid
-Labetolol
-Cyclosproine and tacrolimus
-Isoretinoic acid
-VIncristine
-Alcohol

Question 6

Sensory nerve conduction studies can be mildly abnormal in which neuromuscular/muscle disorders (2)?

Answer 6

-Lambert-Easton myasthenic syndrome
-Inclusion body myositis