Collagen vascular diseases

From WikiCNS

Diffuse group of diseases including vasculitis, lupus, progressive systemic sclerosis, polymyositis/dermatomyositis, polyarteritis nodosa, and Wegener’s granulomatosis

1. vasculitis see segmental inflammatory lesions in the media or adventitia – e.g. erythema nodosum, polyarteritis nodosa, giant-cell arteritis, and Takayasu’s arteritis
   1. affect mostly distal intracerebral arteries with distal aneurysm formation
2. polymyositis – subacute to chronic symmetrical weakness of proximal limb and trunk muscles without dermatitis; unknown cause
   1. female predominance; painless weakness of proximal limb muscles especially of hips and thighs moreso than distal weakness; often affects esophagus
   2. pain is present in about 30% of patients
   3. atrophy and reduction in tendon reflexes; absence of sensory findings
   4. serum CK is 5-10 times normal with elevated liver enzymes as well
   5. single fiber necrosis and phagocytosis is seen in polymyositis; endomysial inflammatory exudates with large number of T cells are present
3. dermatomyositis
   1. dermatomyositis affects children and adults equally with female predominance
   2. symptoms similar to polymyositis along with diffuse erythema, maculopapular eruption, scaling eczematoid dermatitis, or exfoliative dermatitis – often on the bridge of the nose or around the eyes; respiratory muscles are rarely affected
   3. both dermatomyositis (15%) and polymyositis (9%) are associated with carcinoma
   4. in both polymyositis and dermatomyositis, serum levels of creatine kinase (CK) are elevated
   5. perifascicular muscle fiber degeneration and atrophy is seen in dermatomyositis; IgG, IgM, and complement are deposited in the vessels of patients with dermatomyositis
   6. EMG findings:
      1. EMG is helpful but normal in about 15% of cases; usually see a myopathic pattern with many abnormally brief action potentials at low voltage and numerous fibrillation potentials, trains of positive sharp waves, occasional polyphasic units and myotonic activity
   7. Childhood dermatomyositis is a separate entity and is associated with pain in about 50% of cases
   8. Pathologically in both polymyositis and dermatomyositis see widespread destruction of segments of muscle fibers, necrosis, phagocytosis
   9. Treatment: corticosteroids with favorable prognosis; complete recovery in 20% while most do well after several years of treatment