Path- Myopathies

Question 1

Wernig-Hoffmann Disease

Answer 1

Most common form of denervation atrophy where alpha motor neurons are damaged from birth

Question 2

W-H Indications

Answer 2

Congenital and results in floppy baby syndrome. Death within three years of birth and no treatment available. Lower motor neuron disease affecting ventral horn and causing atrophy of muscle

Question 3

Duchenne MD

Answer 3

Severe form of muscular dystrophy where there is no dystrophin present in muscle fibers. X-linked. Muscle biopsy reveals grouped atrophy and centralized nuclei. High creatine kinase seen at first then drops as muscle atrophies

Question 4

Pseudohypertrophy

Answer 4

Important clinical finding in DMD where muscle is replaced by fat, commonly seen in calf

Question 5

Becker’s MD

Answer 5

Less severe form of muscular dystrophy where there is altered dystrophin. Does not usually fatal like DMD early in life

Question 6

Myotonic Dystrophy

Answer 6

Most common form of adult muscular dystrophy that presents with impaired muscle relaxation. Atrophy of type 1 fibers and hypertrophy of type 2 fibers

Question 7

Myotonic Clinical Findings

Answer 7

Patient will complain of stiffness and unable to relax muscles. Affects facial and jaw muscle as well.

Question 8

Congenital Myotonic MD

Answer 8

Present with “tented” or inverted “V” shape of upper lip

Question 9

Thyrotoxic Myopathy

Answer 9

Proximal muscle weakness due to decreased thyroid function. Results in muscle cramps and slowed movements/reflexes. More common in men

Question 10

Ethanol Myopathy

Answer 10

High levels of ethanol causes rhabdomyolysis (muscle break down that becomes necrotic) and increased in binge drinking

Question 11

Drug-induced Myopathy

Answer 11

Steroids cause muscle atrophy of type 2 fibers

Chloroquine (anti-malarial)

Question 12

Myasthenia Gravis

Answer 12

Autoimmune disease with loss of Ach receptors. Present with muscle weakness and commonly seen with thymic hyperplasia. See decreased nerve conduction with repetitive stimulation

Question 13

MG Treatment

Answer 13

Treat by giving anticholinesterase to promote more Ach in synapse

Question 14

Lambert-Eaton Syndrome

Answer 14

Disease of the neuromuscular junction that causes proximal muscle weakness. May be due to autoimmunity to Ca. Commonly associated with small cell carcinoma of lung

Question 15

LE Treatment

Answer 15

Anticholinesterase does not help treatment, increased nerve conduction with repetitive stimulation