Lecture notes:
Hairy cell leukemia – cytoplasmic projections; acid phosphatase +
ALL – kids; CD10, TdT positive; Down syndrome –> can cause ALL and AML, but ALL more, especially in kids
Leukemias are usually B cell. If the USMLE wants T cell, you’ll get a positive Pemberton sign with an SVC-like syndrome (superior vena cava-like syndrome), where there’s flushing of the face with arms above the head. This is due to thymic lesion with compression of SVC seen in T cell variant.
6-mercaptopurine used in Tx of ALL. Pure synthesis inhibitor. When used in the treatment of leukemia, can cause tumor lysis syndrome (high K+, high phosphate, low Ca, low bicarb, high uric acid). However, don’t give a xanthine oxidase inhibitor such as allopurinol or febuxostat to prevent tumor lysis syndrome in the specific case of a patient receiving 6-MP (or azathioprine, which is metabolized into 6-MP) bc 6-MP requires xanthine oxidase for breakdown. 6-MP is activated by HGPRT ( same enzyme deficient in Lesch-Nyhan syndrome; XR).
If ALL, lymphocyte count will be super high. Normal is 4-11k. But you’ll see like 30k+.
Pertussis (whooping cough) has super high lymphocyte count for whatever reason (instead of neutrophils). Can resemble ALL based on bloods. But of course you’d have presentation of whooping cough instead.
AML you get Auer rods on smear, which are myeloperoxidase +; APL (type M3 AML) is t(15;17) translocation; can treat with all-trans retinoic acid.
CLL causes smudge cells on smear; can also cause warm autoimmune hemolytic anemia; CD5 and CD23 positive
CML they like myelocytes and metamyelocytes elevated; these are almost buzzwordy they’re so HY.
Don’t forget imatinib is Tx for CML; causes fluid retention (peripheral edema). Drug targets bcr-abl tyrosine kinase.
