Monoclonal proliferation of plasma cell line causing disease
Classification
Monoclonal gammopathy of unknown significance (MGUS)
M-protein present but <30 g/L, and
Plasma cells <10% of bone marrow
Absence of multiple myeloma end-organ damage
If IgM, must also have no symptoms of a proliferative disorder or hyperviscosity
Must think about Waldenstrom macroglobulinemia
Smoldering myeloma
IgG or IgA M-protein >30 g/L or urinary M-protein (Bence-Jones) >500 mg/24h or plasma cells 10-60%
Absence of multiple myeloma end-organ damage
Multiple myeloma
SLiM CRAB symptoms
Sixty percent plasma cells in marrow
Light chain ratio (κ:λ or λ:κ) >100
MRI showing at least two focal lesions
Hypercalcemia >2.75 mmol/L
Renal failure with creatinine >177 µmol/L or CrCl <40 mL/min
Anemia with hemoglobin <100 g/L
Bony lytic lesions
Clinical Manifestations
Complications
Acute kidney injury
Light chain deposition
Hypercalcemia
Urate crystals
Amyloid deposition
Myeloma infiltration
Diagnosis
Routine bloodwork
CBC with peripheral blood film, for anemia
Calcium and creatinine
SPEP with immunofixation
Quantitative immunoglobulins
Urinalysis
UPEP with immunofixation
Bone marrow biopsy
Imaging
Bone survey including spine, pelvis, skull, humeri, and femurs
Add low-dose whole-body CT or MRI for smoldering myeloma and solitary plasmacytoma
Management
Antimicrobial Prophylaxis
Levofloxacin 500 mg p.o. daily for the first 12 weeks after starting chemotherapy may reduce mortality[1]
↑Drayson MT, Bowcock S, Planche T, Iqbal G, Pratt G, Yong K, Wood J, Raynes K, Higgins H, Dawkins B, Meads D, Hulme CT, Monahan I, Karunanithi K, Dignum H, Belsham E, Neilson J, Harrison B, Lokare A, Campbell G, Hamblin M, Hawkey P, Whittaker AC, Low E, Dunn JA; TEAMM Trial Management Group and Trial Investigators. Levofloxacin prophylaxis in patients with newly diagnosed myeloma (TEAMM): a multicentre, double-blind, placebo-controlled, randomised, phase 3 trial. Lancet Oncol. 2019 Dec;20(12):1760-1772. doi: 10.1016/S1470-2045(19)30506-6. Epub 2019 Oct 23. PMID: 31668592; PMCID: PMC6891230.
References
^Mark T Drayson, Stella Bowcock, Tim Planche, Gulnaz Iqbal, Guy Pratt, Kwee Yong, Jill Wood, Kerry Raynes, Helen Higgins, Bryony Dawkins, David Meads, Claire T Hulme, Irene Monahan, Kamaraj Karunanithi, Helen Dignum, Edward Belsham, Jeff Neilson, Beth Harrison, Anand Lokare, Gavin Campbell, Michael Hamblin, Peter Hawkey, Anna C Whittaker, Eric Low, Janet A Dunn. Levofloxacin prophylaxis in patients with newly diagnosed myeloma (TEAMM): a multicentre, double-blind, placebo-controlled, randomised, phase 3 trial. The Lancet Oncology. 2019;20(12):1760-1772. doi:10.1016/s1470-2045(19)30506-6.
