MUSCULOSKELETAL PATHOLOGY-1

Question 1

What’s the pathogenesis of the condition described?

Myotonia (prolonged muscle contractions)

Cataracts

Frontal balding

Testicular atrophy

Elevated creatine kinase

Glucose intolerance

Answer 1

expansions of CTG triplet repeats in the 3′-noncoding region of the myotonic dystrophy protein kinase (DMPK) gene on chromosome 19

Question 2

Dermatomyositis OR Polymyositis?

scaling erythematous eruption or dusky red patches over the knuckles, elbows, and knees proximal muscle weakness

difficulty getting up from a chair

anti Mi-2 antibodies

Answer 2

Dermatomyositis

Question 3

Which is the inflammatory myopathy that occurs as a paraneoplastic syndrome assoc with Adenocarcinomas, especially ovarian?

Answer 3

Dermatomyositis

Question 4

Mechanism of action of the neurotoxin produced by Clostridium botulinum

Answer 4

blocks the release of acetylcholine from presynaptic neurons

Question 5

List 5 difference between Myasthenia Gravis and Lambert Eaton Syndrome

Answer 5

Question 6

antibodies that block acetylcholine release by inhibiting a presynaptic calcium channel

Answer 6

Lambert-Eaton Myasthenic Syndrome

Question 7

Mode of inheritance?

an inability to lift the trunk without using the hands and arms to brace and push

total absence of dystrophin

Calf pseuodhypertrophy

Answer 7

Xlinked recessive (Duchenne’s)

Question 8

What are the 2 key morphologic findings assoc with Duchenne muscular dystrophy?

Answer 8

1. segmental myofiber degeneration and regeneration
2. fatty replacement

Question 9

Morphologic finding in dermatomyositis

Answer 9

Perimysial inflammation with perifascicular atrophy

Question 10

1. What’s your diagnosis?

proximal muscle weakness

No cutaneous manifestations

↑↑Creatine kinase, aldolase, myoglobin

↑Anti–Jo-1

↑ESR/CRP

2. What’s the assoc morphologic finding?

Answer 10

1. Polymyositis
2. endomysial inflammation with CD8+ T cells.

Question 11

Dermatomyositis OR Polymyositis?

endomysial inflammation with CD8+ T cells

Answer 11

Polymyositis

Question 12

autoantibodies directed against postsynaptic acetylcholine receptors

Deborah Dalmeida MD

Answer 12

Myasthenia Gravis

Deborah Dalmeida MD

Question 13

What is the genetic basis for difference in clinical presentation between Duchenne and Becker dystrophy?

Answer 13

Allelic heterogenity

PS: Allelic heterogeneity is Different mutations in the same locus producing the same phenotype.

Question 14

Dermatomyositis OR Polymyositis?

infiltrate rich in CD4+ T-helper cells and the deposition of C5b-9 in capillary vessels of skeletal muscle

Answer 14

Dermatomyositis

Question 15

In Proximal muscle weakness with type II atrophy following prolonged corticosteroid therapy - Is creatine kinase elevated or normal?

Answer 15

Normal

Question 16

Myasthenia Gravis/Lambert Eaton Syndrome?

rapid repetitive stimulation increases muscle response

Answer 16

Lambert Eaton

Question 17

In statin induced toxic myopathy , is creatine kinase elevated or normal?

Answer 17

Elevated

Question 18

What is the pathogenesis of the condition described below?

an inability to lift the trunk without using the hands and arms to brace and push

delayed walking and clumsiness

see attached image

Answer 18

total absence of dystrophin

Question 19

Diagnosis?

fatigue

headache

Multiple, symmetric tender spots over joints, muscles, tendons

No evidence of muscle inflammation or increase in enzymes

Answer 19

Fibromyalgia

Question 20

List 4 morphologic features of Duchenne muscular dystrophy in the attached muscle biopsy

Answer 20

Question 21

Mode of inheritance?

Myotonia (prolonged muscle contractions)

Cataracts

Frontal balding

Testicular atrophy

Answer 21

Autosomal dominant

Question 22

Myasthenia Gravis/Lambert Eaton Syndrome?

decrement in muscle response with repeated stimulation

Answer 22

Myasthenia Gravis

Question 23

1. What is your diagnosis?

Muscle pain and stiffness in the: Neck, Shoulder and Pelvic girdle

Creatine kinase normal

Known association with Giant cell (temporal) arteritis

Answer 23

Polymyalgia rheumatica

Question 24

1. Dermatomyositis OR Polymyositis?

• lilac colored discoloration of the upper eyelids associated with periorbital edema
  2. What is the antibody assoc with the condition described above ?

Answer 24

1. Dermatomyositis
2. anti Mi-2 antibodies

Question 25

Dermatomyositis OR Polymyositis?

Perimysial inflammation and perifasicular atrophy

Answer 25

Dermatomyositis

Question 26

What is the basis for the condition described?

Exposure to a halogenated inhalational anesthetic leading to :

Tachycardia

Tachypnea

Muscle spasms

Hyperpyrexia

Rhabdomyolysis

Answer 26

The condition described is malignant hyperthermia caused by

Mutations in the RYR1 gene that disrupts the function of the ryanodine receptor

Question 27

In hypothyroidism associated myopathy, is creatine kinase normal or elevated?

Answer 27

Elevated

Question 28

Type of cardiomyopathy assoc with Duchenne muscular dystrophy

Answer 28

DIlated cardiomyopathy

Question 29

What’s the most likely complication described in this patient?

Known case of Tuberculosis

Fever, back/flank pain, inguinal mass, difficulty walking

Pain referred to hip and knee

Pain exacerbated by hip extension

Answer 29

Psoas abscess