Wednesday, January 13, 2010
January 11th - LBJ - Polymyositis/Dermatomyositis and Rheum Labs
Here is an overview of the inflammatory myopathies and some rheum labs to know for boards
The 3 Inflammatory Myopathies you should know about for boards are Polymyositis, Dermatomyositis and and Inclusion Body Myositis
Polymyositis and Dermatomyositis: Proximal Muscle Weakness. Classically they have difficulty "rising from a chair." Also they can have trouble lifting their head up and trouble climbing stairs.
Pain is not frequently present in these patients (myalgias in less than 30%), it is more muscle weakness. Arthralgias may be present, and pharyngeal weakness can lead to dysphagia/aspiration.
Dermatomyositis is essentially Polymyositis with a rash, but with more to know on this in a bit
1. Symmetrical weakness of limb girdle muscles
2. Muscle Biopsy showing necrosis and perifasicular atrophy
3. Elevated Muscle Enzymes (Can be any - CK, Aldolase, LDH and AST are the most often used)
4. EMG with small action potentials, sharp waves and high frequency discharges
Definite Polymyositis is all 4 above
Definite Dermatomyositis is 3/4 above + Skin/Rash Findings c/w disease
For Boards, here is a quick Antibody Review For You:
ANA - Positive is so many things.... SLE, Scleroderma, Sjogrens, Mixed Connective Tissue, Myopathies