Friday, December 18, 2009

December 18th - LBJ - AML and Quick Leukemia Info

Today at LBJ a case of AML was presented.  Here is some more detailed info about AML, all you'll need for boards...

We see the leukemias very often in morning report, so I will post more details on other leukemias as we have cases in MR. 

However, from a clinical/ board recognition standpoint - I have put the salient clinical and lab features of the other leukemias. Especially the labs! This is how you can tell on boards, clinically and in MR which is which!!!

Epidemiology: By far, the majority of acute leukemias are AML (>80%)

Risk Factors: Radiation Exposure, Chemotherapy, Benzene Exposure, Genetic Diseases (i.e. Downs, Bloom Syndrome) and Preexisting Heme Diseases such as MDS, Myeloproliferative disorders, PNH

Patients present with: Constitutional symptoms, bone/testicular pain, gum infiltration, splenomegaly, LAD
NOTE: Since platelets and hemoglobin are usually decreased on diagnosis - patients can present with these findings (i.e. pallor, fatigue and petechiae)  Also, a leukostasis syndrome can be present in patients with WBC Counts that are >100,000: Hypoxia, pulmonary infiltrates, retinal hemorrhage, priapism, CVA, Myocardial infarction, etc. 

Patients with AML on presentation are invariably anemic and thrombocytopenic.  Most patients will actually have severe thrombocytopenia (<50,000).  So what about the white count?? Well, it can be down, slightly elevated or very high. So AML can have pancytopenia OR a modest to very high WBC count with anemia and thromboctyopenia.  Remember This!!!!

The Blood Smear/Differential will have >20 Blasts in most cases. The Auer rod is diagnostic that the cell line is myeloid in nature (see picture!)
and represents AML.  Heme Path docs can tell this is the case by special stains.

Bone Marrow is done for cytogenetics in order to tell prognosis, and to guide treatment.  Favorable types include t(15;17), t(8;21) and inv(16).  Poor cytogenetic profiles include inv(3), del 5 and del 7

There are 8 subtypes of AML by the WHO - you'll probably have to only know about acute promyelocytic leukemia - M3 - has translocation (15;17) - can present with DIC.  Treat with high dose ATRA (all trans-retinoic acid)

The patient undergoes "Induction" and "Consolidation" in a "7" + "3" method
Induction: Given 7 days of IV Cytarabine (Ara-C) plus 3 days of bolus Anthracysline (Idarubicin or Daunorubicin are used) - after this induction, patient will be severely pancytopenic. 
Then the consolidation phase:  Patients are usually given either high dose Ara-C or undergo Bone Marrow Transplant at this stage.  Allogeneic Bone Marrow Transplant or Autologous stem cell transplant  is usually reserved for patients with high-risk/poor prognostic cytogenetics. 

Treatment of patients with the leukostasis syndrome is with hydroxyurea and/or leukopheresis

CLL:  Patients are usually asymptomatic at time of diagnosis.  Constitutional symptoms are rare.  1/3rd will have significant LAD and/or organomegaly. Some patients may have signs/symptoms of anemia.
Labs with CLL:  Patients usually have modestly elevated WBC counts.  Patients will usually be anemic.  The WBC Count Rarely gets highly elevated (i.e. >30,000) and Thrombocytopenia is uncommon.
Smear with mature lymphocytes and smudge cells. 

CML:  Patients can present exactly like CLL - meaning they rarely have constitutional symptoms.  Lymphadenopathy is RARE with CML (as compared to CLL) but patients usually have organomegaly (especially splenomegaly). In fact, abdominal pain/fullness or early satiety are the common presenting symptoms (both on boards and I've seen in patients) due to splenomegaly.  They can also have a leukostasis syndrome like in AML, but this is rare unless the blast count is very high.  Remember that CML is a MYELOPROLIFERATIVE Disorder.  That being said: The WBC count is always high.  This is always the case.   The Hemoglobin can be low, normal or high. The platelet count is either normal or high. 
Smear with immature cells - promyelocytes, metamyelocyes and myelocytes.  Patients can have increased basophils and/or eosinophils as well. 

ALL: Rare in adults compared to other leukemias.   What you'll need to know, for the most part - can present just like AML - lymphadenopathy, organomegaly, etc.  Can also get leukostasis syndrome as the WBC count can get very high.... but can also have a low WBC count. Just like AML:  Pancytopenia OR a modest to very high WBC count with anemia and thromboctyopenia. However, since it is a disease of lymphoid lineage - unlike AML - the smear will show predominantly lymphoblasts.   

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