2 of these disease are seen often on both the heme consult service and boards.
Cold Agglutinin Disease
Hemolytic anemia precipitated by cold
Monoclonal IgM binds RBCs (I antigen), agglutination, and fixes complement in cold->hemolysis
DAT+ for C3 and - for IgG
Associated with IgM gammopathies/LPL
Polyclonal form after Mycoplasma infection
Rx = Rituximab
Cold polyclonal IgG (Donath Landsteiner Ab)
Unlike cold-reacting IgM, no RBC agglutination
But able to fix 1st 2 components of complement in cold
Antibody dissociates at warmer temps
Complement cascade completed on rewarming and hemolysis occurs
Paroxysmal cold hemoglobinuria
Polyclonal IgG specific to P antigen of RBC
DAT positive (anti-C3)
Associated with upper respiratory infections
Historically associated with secondary or tertiary syphilis
Clinical manifestations: Dark urine after exposure to cold
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The only blood smears you need to know for the USMLE
Brief Tweetorial
5 Leukemias
5 Blood smears
Be able to differentiate them
1. AML 2. ALL 3. CML 4. CLL 5. Adult T-cell leukemia/lymphoma
AML
Typically older patient, although can occur in younger patients.
Abrupt symptoms
Needs urgent Rx
Myeloblasts have Auer rods, but not always
However, if Auer rod seen it has to be AML
APL subtype t(15;17) commonly has Auer rods!
ALL
Question will typical have child 1-9, although can occur in older patients.
Mediastinal mass possible usually T-cell (unlike AML) Abrupt symptoms
Needs urgent Rx
ALL blasts look like AML blats
Would be tricky ? to identify based only on smear Absolutely no Auer rods
Diagnostic testing for monoclonal gammopathies!
A tweetorial for internists to clear some confusion!
Serum protein electrophoresis(SPEP)
Urine protein electrophoresis (UPEP)
Serum immunofixation (SIFE)
Urine immunofixation (UIFE)
Serum free light chains(sFLC) (kappa/lambda)
Electrophoresis (SPEP/UPEP) = how much
Charge based separation of protein on gel
Low sensitivity
May miss small monoclonal proteins and light chains
Quantifies M-protein (g/dL)
Does not qualify M-protein (IgG, IgA, IgM, IgD, IgE)
Immunofixation = Determines the flavor
Ab’s against the heavy chains and κ and λ light chains
Allows for identification of isotype (IgG, IgA, IgM, IgD, IgE)
Detection of small proteins missed on electrophoresis
More sensitive than SPEP
Unlike SPEP/UPEP, not quantitative
Brief Tweetorial
5 Leukemias
5 Blood smears
Be able to differentiate them
1. AML 2. ALL 3. CML 4. CLL 5. Adult T-cell leukemia/lymphoma
AML
Typically older patient, although can occur in younger patients.
Abrupt symptoms
Needs urgent Rx
Myeloblasts have Auer rods, but not always
However, if Auer rod seen it has to be AML
APL subtype t(15;17) commonly has Auer rods!
ALL
Question will typical have child 1-9, although can occur in older patients.
Mediastinal mass possible usually T-cell (unlike AML)
Abrupt symptoms
Needs urgent Rx
ALL blasts look like AML blats
Would be tricky ? to identify based only on smear
Absolutely no Auer rods