APML Is Medical Emergency

11 Mar, 2021

Dr. Rajesh Bollam

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#APML is medical emergency
APML : 8% of adult AML cases. Median age 47
🏥can present w pancytopenia & associated sx (fatigue, SOB, bleed/bruise). Leukocytosis (like in this case) is a marker of high-risk disease
🩺Dx: t(15,17) translocation (that results in fusion of PML-RAR gene). You don't need 20% blasts if that's present
Pathophys: PML-RARA fusion protein blocks differentiation ➡️ cells are stuck in the promyelocyte stage
🪦Prognosis: w/o tx, short term survival is very poor! Median survival is <1 mo.
🧠🩸A major cause of this is hemorrhage! Up to 40% can have a fatal head bleed
🚨That's why coagulopathy & APL = medical emergency!
Simplified into 2 main mechanisms:
🩸DIC
(unlike in sepsis there are higher levels of Protein C&S in APL hence ⬆️ bleeding)
✂️Hyperfibrinolysis
Annexin II (expressed on blasts) ⬆️ plasmin by tPA dependent mechanism ⏩ fibrinolysis.
But why are pts with APL so prone to bleeding?
Therefore w acute leukemia (& esp if APL is suspected):
☑️ Do a neuro exam (⬆️head bleed in APL)
☑️ Check Plt, D-dimer, fibrinogen, INR & have a low transfusion threshold: Fibrinogen >150, plt >30-50,INR <1.5
✅ATRA as soon as you *SUSPECT* APL (don't need confirmed dx)
💊ATRA promotes the terminal differentiation of malignant immature promyelocytes to mature neutrophils!
🌟Despite high early mortality, with treatment, remission rates can be >90% !!
Take home points:
🏠Acute leukemia? Look for DIC/bleeding, TLS, febrile neutropenia, leukostasis
🏠Pts. with APL have high short term mortality & high risk of bleeding. Make sure you check coags & do a neuro exam
🏠Start ATRA if you suspect APL!

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