- Medium-vessel vasculitis caused by antigen-antibody complex deposition
- Type I monoclonal→ IgM or IgG related to lymphoprolif d/o→ lymphoma, myeloma
- Type II and III, mixed cryos IgM and IgG related to Hep C (most common), SLE, RA, lymphoma, myeloma, HIV, hep b, other autoimmune
- Affects multiple systems (nerves, lungs, kidneys, etc.)
- Subacute fatigue
- Muscle and joint aches
- Cough/sob if pulmonary involvement
- Symmetric or asymmetric often painful distal neuropathy
- Painful skin ulcers of extremities
- Purpuric papules
- Membranoproliferative glomerulonephritis
- Palpable purpura of vasculitis
- Livedo reticularis
- Distal skin ulcers
- Peripheral neuropathy related: decreased distal sensation, weakness, diminished reflexes
- Other tests to identify underlying cause (e.g. Hep C ab/viral load, HIV, ANA, SPEP, etc)
- Serum: + cryoglobulins, low C3, + RF
- W/Renal involvement: UA + RBCs, protein; Urine microscopy w/rbc casts, dysmorphic RBCs; Serum: decrease in GFR