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Toronto Notes 2019 Complications of Hematologic Malignancies Hematology H51 Monoclonal Gammopathy of Unknown Significance
Definition
• presenceofMproteininseruminabsenceofanyclinicalorlaboratoryevidenceofaplasmacell dyscrasia or lymphoproliferative disorders
■ incidence: 0.15% in general population, 5% of people >70 yr of age ■ asymptomatic
Diagnosis
• presenceofaserummonoclonalprotein(Mprotein)ataconcentration<30g/L
• <10%plasmacellsinbonemarrow
• absenceofhyperCalcemia,Renalinsufficiency,Anemia,Bonydiseaserelatedtotheplasmacell
proliferative process (absence of “CRAB”)
• 0.3-1%ofpatientsdevelopahematologicmalignancyeachyr
■ patients with M protein peak ≥15 g/L or patients with IgA or IgM MGUS are at higher risk of malignant transformation
■ patients with abnormal serum free light chains ratio are at increased risk of malignant transformation
• monitorwithannualhistory,physical,CBC,Cr,calcium,albumin,andserumproteinelectrophoresis (considered pre-malignant)
Lymphoplasmacytic Lymphoma (Waldenstrom’s Macroglobulinemia)
Definition
• proliferationoflymphoplasmacytoidcells
■ presence of monoclonal IgM paraprotein
Clinical Features
• chronicdisorderofelderlypatients;medianage64yr
• symptoms:weakness,fatigue,bleeding(oronasal),weightloss,recurrentinfections,dyspnea,CHF
(triad of anemia, hyperviscosity, plasma volume expansion), neurological symptoms, peripheral
neuropathy, and cerebral dysfunction
• signs:pallor,splenomegaly,hepatomegaly,lymphadenopathy,andretinallesions
• keycomplicationtoavoid:hyperviscositysyndrome
■ because IgM (unlike IgG) confined largely to intravascular space
Investigations and Diagnosis
• bonemarrowshowsplasmacytoidlymphocytes
• bonelesionsusuallynotpresent
• bloodworkrarelyshowshypercalcemia
• coldhemagglutinindiseasepossible:Raynaud’sphenomenon,hemolyticanemiaprecipitatedbycold
weather
• normocyticanemia,rouleaux,andhighESRifhyperviscositynotpresent
Treatment
• Bendamustine–R/R-CVPchemotherapy,alkylatingagents(chlorambucil),nucleosideanalogues (fludarabine), rituximab, or combination therapy
• corticosteroids
• plasmapheresisforhyperviscosity:acutereductioninserumIgM
Complications of Hematologic Malignancies
Hyperviscosity Syndrome
Definition
Waldenstrom’s macroglobulinemia accounts for 85% of all cases of hyperviscosity syndrome
• referstoclinicalsequelaeofincreasedbloodviscosity(whenrelativeserumviscosity>5-6units), resulting from increased circulating serum Igs or from increased cellular blood components in hyperproliferative disorders (e.g. multiple myeloma, leukemia, PV)
• Waldenstrom’smacroglobulinemiaaccountsfor85%ofcases
Clinical Features
• hypervolemiacausing:CHF,headache,lethargy,dilutionalanemia
• CNSsymptomsduetodecreasedcerebralbloodflow:headache,vertigo,ataxia,andstroke • retinashowsvenousengorgementandhemorrhages
• bleedingdiathesis
■ due to impaired platelet function, absorption of soluble coagulation factors (e.g. nasal bleeding, oozing gums)
• ESRusuallyverylow
Treatment
• plasmapheresis, chemotherapy