Muscle Disorders B&B

Question 1

how is polymyalgia rheumatica diagnosed and treated?

Answer 1

inflammatory muscle disorder of unknown cause occurring in patients 50+

diagnosed clinically (no pathognomonic test), but commonly occurs with temporal arteritis (inflammation of temporal vein) + high levels of CRP and ESR

responds well to glucocorticoids

Question 2

inflammatory disorder in older patients of unknown cause, presenting with bilateral proximal muscle stiffness (esp. in the morning) but normal strength testing and CK levels

Answer 2

polymyalgia rheumatica: diagnosed clinically, often occurs with temporal arteritis, treated with glucocorticoids

Question 3

Pt is a 73yo presenting with proximal muscle stiffness in the bilateral neck, shoulders, and hips which is worse in the morning and makes it difficult to get dressed. However, strength testing is normal (no muscle weakness), as is the CK level. However, CRP and ESR levels are elevated. What is the diagnosis, and how will you treat it?

Answer 3

polymyalgia rheumatica: inflammatory disorder of unknown cause, diagnosed clinically, presents with bilateral proximal muscle stiffness + shoulder myalgia

inflammation is in joints, muscles are actually healthy —> normal testing

responds well to glucocorticoids

Question 4

how is fibromyalgia diagnosed? which patients are most affected?

Answer 4

chronic disorder of widespread musculoskeletal pain of unknown cause - labs/biopsy are normal, diagnose clinically

common in women (20-55yo), about half have depression/anxiety —> treat with exercise, tricyclic antidepressants, SSRIs

Question 5

what is the hallmark presentation of inflammatory myopathies such as polymyositis and dermatomyositis?

Answer 5

autoimmune muscle disorders causing myalgias and slow onset symmetric muscle weakness which begins proximally and spreads distally over time

affects muscles close to midline —> difficulty rising from chair, climbing stairs, combing hair, etc

Question 6

what are the typical lab findings of inflammatory myopathies such as polymyositis and dermatomyositis? (3)

Answer 6

autoimmune disorders causing symmetric muscle weakness that moves proximal —> distal

1. elevated creatinine kinase (CK)
2. anti-nuclear antibodies (ANA) - nonspecific
3. anti-Jo1 antibodies (against histidyl t-RNA synthetase)

Question 7

polymyositis vs dermatomyositis

Answer 7

both autoimmune disorders causing symmetric muscle weakness that moves proximal —> distal

polymyositis: inflammation of endomysium (surrounds myocyte) by CD8 T cells

dermatomyositis: inflammation of perimysium (surrounds fascicles) by CD4 T cells + skin findings

Question 8

which 2 classic skin findings are associated with dermatomyositis?

Answer 8

form of autoimmune inflammatory myopathy due to inflammation of perimysium (surrounds fascicles) by CD4 T cells + skin findings

1. heliotrope rash: purple discoloration of upper eyelid (heliotrope = purple plant)
2. Grotton papules: red/scaly on hand/fingers

both are pathognomonic!

Question 9

heliotrope rashes and grotton papules are both pathognomonic for…

Answer 9

dermatomyositis: form of autoimmune inflammatory myopathy due to inflammation of perimysium (surrounds fascicles) by CD4 T cells + skin findings

1. heliotrope rash: purple discoloration of upper eyelid (heliotrope = purple plant)
2. Grotton papules: red/scaly on hand/fingers

both are pathognomonic!

Question 10

which type of malignancies are associated with inflammatory myopathies such as polymyositis and dermatomyositis?

Answer 10

autoimmune disorders causing symmetric muscle weakness that moves proximal —> distal

associated with adenocarcinomas (DM > PM)

Question 11

myalgias + symmetric proximal muscle weakness (difficulty climbing stairs, combing hair, etc) + elevated CK (creatinine kinase) and anti-Jo1 antibodies + endomysial inflammation and CD8 T-cells on muscle biopsy =

Answer 11

polymyositis: form of inflammatory myopathy due to endomysial inflammation by CD8 cells —> symmetric muscle weakness moves proximal to distal