Plasma cell proliferation usually in older people - incurable but very treatable
CRAB diagnostic criteria:
Calcium ↑ - increased osteoclast activity causes calcium reabsorption from the bone into the blood → hypercalcaemia
Renal insufficiency - various causes. Paraproteins, hypercalcaemia, dehydration, glomerulonephritis, medications
Anaemia - most common complication (normocytic and normochromic). Marrow infiltration results in suppression of the other blood cell lines leading to anaemia, leukopenia and thrombocytopenia.
Bone lesions - increased osteoclast and suppressed osteoblast activity due to cytokines released from abnormal plasma cells. Most common sites are skull, spine, long bones and ribs. Patchy areas of very thin bone - osteolytic lesions which can lead to pathological fractures
- Proceeded by asymptomatic MGUS (monoclonal gammopathy of undetermined significance) in all patients
- Treatment with steroids, and chemotherapy
Complications:
- Hyperviscosity (especially with IgA + IgM as they are larger molecules)
- Sepsis
- Spinal cord compression