Hematology and Oncology

Iron deficiency:- Serum iron: ↓- Transferrin or TIBC: ↑- Ferritin: ↓- % transferrin saturation (serum iron/TIBC): ↓↓ Chronic disease:- Serum iron: ↓- Transferrin or TIBC: ↓- Ferritin: ↑- % transferrin saturation (serum iron/TIBC): – Hemochromatosis:- Serum iron: ↑- Transferrin or TIBC: ↓- Ferritin: ↑- % transferrin saturation (serum iron/TIBC): ↑↑ Pregnancy/OCP use:- Serum iron: –- Transferrin or TIBC: ↑- Ferritin: –- % transferrin saturation (serum iron/TIBC): ↓

High mortality rate with accidental ingestion by children (adult red iron tablets may look like candy). Mechanism: Cell death due to peroxidation of membrane lipids. Symptoms: Nausea, vomiting, gastric bleeding, lethargy, scarring leading to GI obstruction. Treatment: Chelation (eg, IV deferoxamine, oral deferasirox) and dialysis.

Inherited deficiency of antithrombin: has no direct effect on the PT, PTT, or thrombin time but diminishes the increase in PTT following heparin administration. Can also be acquired: renal failure/nephrotic syndrome → antithrombin loss in urine → ↓ inhibition of factors IIa and Xa.

Mutation in 3' untranslated region → ↑ production of prothrombin → ↑ plasma levels and venous clots.

- Occurs in adults - t(11;18) - Associated with chronic inflammation (eg, Sjögren syndrome, chronic gastritis [MALT lymphoma])

B-cell lymphoma- Occurs in adults - Most commonly associated with HIV/AIDS- Pathogenesis involves EBV infection - Considered AIDS-defining illness. - Variable presentation: confusion, memory loss, seizures. - Mass lesion(s) may be ring-enhancing in immunocompromised patient on MRI, needs to be distinguished from toxoplasmosis via CSF analysis or other lab tests.

Oncologic emergency triggered by massive tumor cell lysis, most often in lymphomas/leukemias. Release of K+ → hyperkalemia, release of PO43- → hyperphosphatemia, hypocalcemia due to Ca2+ sequestration by PO43-. ↑ nucleic acid breakdown → hyperuricemia →↑ acute kidney injury. Prevention and treatment include aggressive hydration, allopurinol, rasburicase.

Mutations that cause production of hemoglobin with high oxygen affinity. Low oxygen levels stimulate the kidneys to increase erythropoietin synthesis, which results in a compensatory erythrocytosis that helps maintain normal oxygen delivery. Typically asymptomatic.

Clinical features:- Venous or arterial thromboembolic disease (eg, DVT, PE, ischemic stroke/TIA)- Adverse pregnancy outcomes (eg, unexplained embryonic or fetal loss, premature brith due to placental insufficiency or preeclampsia) Lab findings: - Lupus anticoagulant effect: Paradoxical aPTT prolongation not reversed on plasma mixing studies.- Presence of specific antiphospholipid antibodies (anticardiolipin, anti-beta2-glycoprotein) - These antibodies can cause false-positive results on nontreponemal serologic syphilis tests (eg, RPR and VDRL) by reacting with cardiolipin.

Autosomal recessive disorder of nonhomologous end joining DNA repair. - Aplastic anemia- 50% develop AML or myelodysplastic syndromes- Short stature- Café-au-lait spots- Thumb and radial malformations Labs: Pancytopenia- Anemia- Bleeding gums, nosebleeds- Frequent infections

Normocytic, normochromic anemias are classified as nonhemolytic or hemolytic. The hemolytic anemias are further classified according to the cause of the hemolysis (intrinsic vs extrinsic to the RBC) and by the location of the hemolysis (intravascular vs extravascular). Hemolysis can lead to increases in LDH, reticulocytes, unconjugated bilirubin, urobilinogen in urine. Non-hemolytic anemias (reticulocyte count ≤2%):- Aplasic anemia- Chronic kidney disease- Anemia of chronic disease- Iron deficiency (early) Hemolytic (reticulocyte count ≥2%)- Extrinsic: Autoimmune, microangiopathic, macroangiopathic, infections- Intrinsic: Membrane defects, enzyme deficiencies, hemoglobinopathies