Hematology/Oncology Flashcards
Fluctuating sizes of lymph nodes = _____ lymphoma
Follicular
What is 5-HIAA and what is its clinical utility?
A serotonin metabolite. Increased levels will be found in the urine in the setting of carcinoid syndrome.
What is carcinoid syndrome? What are presenting symptoms?
Carcinoid tumors arise from enterochromaffin (endocrine) cells of the intestinal mucosa. When they metastasize to the liver they bypass destruction and thus release their products into the systemic circulation. Most notably: serotonin (5-HT), bradykinin, and prostaglandins.
Symptoms:
Skin flushing, telangiectasias, watery diarrhea, bronchospasm, dyspnea, valvular fibrous plaques
Does CO cause methemoglobin?
NO!
Methemobloginemia is caused by drugs (dapsone, nitrites), enzyme deficiencies, and hemoglobinopathies
Ondansetron, granisetron, and dolasteron are all examples of ________ used in the treatment of _________. How do they work?
5-HT3 (serotonin) receptor antagonists
Treat chemotherapy-induced vomiting.
They work by:
- Blocking the vagus-mediated n/v from Gi tract stimulus
- Central blockage of serotonin receptors in the area protstrema and NTS
What are the 3 drug classes useful in treating chemotherapy-induced vomiting?
- Serotonin receptor antagonists (e.g. ondansetron)
- NK1 receptor antagonists (e.g. arepitant)
- Dopamine receptor antagonists (e.g. metoclopramide)
Why do you get splenomegaly in the setting of pyruvate kinase deficiency?
PK converts PEP to pyruvate in the glycolytic pathway. RBCs do not have mitochondria and thus rely on lactate (made from pyruvate) for glycolysis and thus ATP generation.
Absence of PK reduces ATP -> echinocyte formation and hemolysis. Hemolyzed RBCs are destroyed and eaten up in the spleen by the reticuloendothelial system in the RED PULP. Chronic hemolysis leads to red pulp hyperplasia and splenomegaly.
Etoposide targets Topoisomerase ___, preventing the repair of the double stranded breaks it makes when it relieves positive and negative supercoiling.
II
What lab findings are indicative of hemolytic uremic syndrome (HUS)?
Anemia and thrombocytopenia
Decreased hemoglobin and haptoglobin
Increased serum LDH and indirect (unconjugated) bilirubin
^massive hemolysis overwhelms conjugation abilities
_______ syndrome is characterized by dysphagia due to esophageal web formation, iron deficiency anemia, spoon nails, and a shiny smooth red tongue.
Plummer-Vinson
Tx: iron supplementation
How would nephrotic syndrome end up causing renal vein thrombosis and a varicocoele?
Nephrotic syndrome causes loss of many proteins, including anticoagulant antithrombin III -> hypercoaguable state and renal vein thrombosis.
RVT will cause impaired LEFT gonadal venous drainage -> varicocoele.
_______ balance pro- and anti-apoptotic proteins. When inhibited, proapoptotic proteins build up causing apoptosis. Bortezomib is an example of an inhibitor of these and is used in the tx of _________.
Proteasomes
Multiple Myeloma
Patients with beta thalessemias generate more Hemoglobin ____ to compensate. What is the main deficiency in beta thalessemias?
Hemoglobin A2 (alpha2delta2) is upregulated to compensate.
Occasionally increased HbF
Thalessemias occur due to a variety of DNA mutations affecting the transcription, processing, and translation of beta-globin mRNA (most commonly due to aberrant precursor mRNA splicing or premature chain termination during translation).
What do lead-poisoned RBCs look like? What are symptoms of lead poisoning?
Basophilic stipling
Microcytic hypochromic anemia
Constipation
Mental status change
HER2 ___ (+/-) breast cancers are associated with poorly differentiated, rapidly growing tumors.
HER2 +
HER2 oncogene encodes for a human epidermal growth factor receptor with tyrosine kinase activity in the intracellular domain.
Anti-HER2 monoclonal Abs (e.g. trastuzumab) are now available.
Integrin is important for bridging cell membranes with both INTRA and EXTRAcellular filaments. Intracellular filaments include:
Extracellular include:
Intracellular: actin and keratin
Extracellular: fibronectin, collagen, laminin
TMP-SMX is the drug of choice for PJP. However, in patients with sulfa allergies, dapsone is used instead. What does dapsone put them at risk for?
Methemoglobinemia.
Occurs most often in G6PD-deficient patients.
What are common precipitating factors for G6PD deficiency anemia?
- Infection
- Drugs (dapsone, antimalarials, sulfa drugs)
- DKA
- Favism (ingestion of fresh fava beans)
What do bite cells indicate?
Oxidant-induced RBC damage, e.g. G6PD deficiency
KRAS is a _______ while
APC, BRCA1, RB, and TP53 are all tumor _______
KRAS = proto-oncogene
The rest are examples of tumor suppressors.
What is the most common tumor in HIV-positive individuals?
Kaposi’s Sarcoma caused by HHV-8
Presents as multiple blue-violet or brownish dermal plaques that start on the feet and legs and spread proximally.
Cytokeratins are commonly used immunohistochemical markers for __________ tumors.
Epithelial-derived tumors (e.g. breast cancer)
Angiogenesis is primarily driven by what 2 factors?
VEGF (vascular endothelial growth factor)
and
Fibroblast growth factor (FGF)
How is G6PD deficiency inherited? In which ancestry is it most common?
X-linked (therefore more common in males)
Commonly found in people of African, Asian, and Mediterranean descent.
In question stems, hemolysis caused by sulfa drugs (bactrim, TMP/SMX) is often due to __________.
G6PD deficiency
G6PD is an enzyme in the pentose phosphate shunt necessary for maintaining NADPH (and therefore reduced glutathione needed to relieve RBC oxidative stress)
How does desmopressin (DDAVP) stop bleeding in hemophilia and Type I vWF disease patients?
Increases circulating factor VII and endothelial secretion of vWF to stop bleeding.
How is von Willebrand’s disease inherited?
Autosomal dominant
HHV8/Kaposi’s Sarcoma can cause __ cell lymphoma
B