Hematology & Coagulation Review (Exam Prep)

Flashcards covering hematopoiesis, red cell biology, iron studies, various anemias (iron deficiency, thalassemias, sideroblastic, B12/folate), hemolytic disorders, aplastic anemia, MDS, myeloproliferative disorders, leukemias/lymphomas, coagulopathies (ITP, TTP, DIC, vWD, hemophilias, vitamin K, liver disease), postpartum/coagulation scenarios, and tumor markers. Designed to prepare for exams by reinforcing definitions, differential diagnoses, and typical treatments.

Where are hematopoietic stem cells (HSC) primarily located in adults?

In the bone marrow, predominantly in the heads of long bones (e.g., near the ends of the humerus and femur). HSC differentiate into myeloid and lymphoid progenitors.

What do the myeloid and lymphoid progenitor lines give rise to?

Myeloid progenitors differentiate into red cells, megakaryocytes (platelets), eosinophils, basophils, monocytes/macrophages, and neutrophils. Lymphoid progenitors become T cells, B cells, NK cells, and plasma cells.

What is a reticulocyte and why is reticulocyte count measured in anemia?

A reticulocyte is an immature red blood cell released from the bone marrow; reticulocyte count indicates bone marrow response to anemia (high in hemolysis or blood loss; low in underproduction).

How is iron recycled after red cell destruction?

Iron is recovered from senescent red cells, bound to transferrin, stored as ferritin in the liver, and reused for new red cell production.

What labs define iron deficiency anemia (IDA)?

Low ferritin, high TIBC, low serum iron; may have microcytosis with low MCV and high RDW.

What does the mnemonic 'ticks' stand for in microcytic anemia?

Thalassemia, Iron deficiency, Chronic disease, and Sideroblastic anemia.

How are microcytic, normocytic, and macrocytic anemias defined by MCV?

Microcytic: MCV < 80 fL; Normocytic: MCV 80–100 fL; Macrocytic: MCV > 100 fL.

What is the most important test to differentiate beta-thalassemia from iron deficiency when you see microcytosis with inconclusive iron studies?

Hemoglobin electrophoresis helps differentiate thalassemia (abnormal Hb patterns) from iron deficiency (low ferritin, low serum iron).

How can you differentiate beta-thalassemia from iron deficiency when microcytosis is present?

Beta-thalassemia often has normal or high ferritin with a normal iron panel, but abnormal Hb electrophoresis; iron deficiency shows low ferritin and low serum iron with high TIBC.

What are the thalassemia major and minor presentations for alpha and beta loci?

Beta-thalassemia major presents in infancy with severe anemia; beta-thalassemia minor presents in adulthood. Alpha-thalassemia ranges from silent/trait to HbH disease; hydrops fetalis is incompatible with life.

What is the hallmark feature of beta-thalassemia major on physical exam and imaging?

Frontal bossing and chipmunk facies due to marrow expansion; electrophoresis confirms diagnosis; treatment includes transfusions and chelation; possible splenectomy.

What are features of sideroblastic anemia and its common etiologies?

Microcytic anemia with high iron and ferritin; basophilic stippling; ring sideroblasts on bone marrow; often due to lead poisoning or toxin exposure; remove toxins and chelate as needed.

What distinguishes vitamin B12 deficiency from folate deficiency clinically?

B12 deficiency often has neurologic symptoms (paresthesias, ataxia, cognitive changes) and elevated methylmalonic acid and homocysteine; folate deficiency lacks neuro signs but has elevated homocysteine.

What is pernicious anemia?

Autoimmune destruction of gastric parietal cells leading to intrinsic factor deficiency and malabsorption of vitamin B12.

How is vitamin B12 deficiency treated if absorption is intact versus impaired?

If absorption is intact: intramuscular B12 injections with a typical schedule. If absorption is impaired (e.g., pernicious anemia or gastric bypass): lifelong injections or alternative routes; dietary B12 and fortified foods also help.

What is the hallmark laboratory finding in B12 deficiency?

Macrocytosis with hypersegmented neutrophils on smear; low hemoglobin with elevated MMA and/or homocysteine.

What is aplastic anemia and how is it treated?

Aplastic anemia is pancytopenia with hypocellular bone marrow replaced by fat; causes include drugs and viral infections; management includes stopping offending agent, supportive care, and possibly stem cell transplant.

What is myelodysplastic syndrome (MDS)?

Underproduction with dysplasia in one or more myeloid lineages; increased risk of progression to AML; diagnosed by CBC showing cytopenias and bone marrow showing dysplasia.

What is polycythemia vera (PV) and its key features?

Myeloproliferative disorder with high red cell mass; often a JAK2 mutation; symptoms include headaches, aquagenic pruritus, splenomegaly; treated with phlebotomy, low-dose aspirin, and sometimes ruxolitinib.

What is essential thrombocythemia (ET)?

Myeloproliferative disorder with elevated platelets; erythromelalgia, headaches, splenomegaly, and thrombosis risk; treated with hydroxyurea, plateletpheresis, or anagrelide.

What is chronic myeloid leukemia (CML) hallmark and treatment?

Philadelphia chromosome (t(9;22)) with BCR-ABL; treated with tyrosine kinase inhibitors like imatinib; often presents with splenomegaly and leukocytosis.

What is chronic lymphocytic leukemia (CLL)?

Most common adult leukemia; clonal B-cell malignancy; small mature lymphocytes and smudge cells on smear; often asymptomatic and managed with watchful waiting until progression.

What is acute myeloid leukemia (AML) hallmark and management?

Auer rods in myeloblasts; risk factors include benzene exposure; presents with anemia and thrombocytopenia; treated with chemotherapy and possible stem cell transplant.

What is acute lymphoblastic leukemia (ALL)?

Most common pediatric leukemia; lymphoid blasts; bone marrow and peripheral blood involvement; treated with intensive chemotherapy; high cure rate in children.

What is multiple myeloma and its CRAB features?

Age >65 with hypercalcemia, renal failure, anemia, and bone lytic lesions; M-spike on SPEP/UPEP; Bence Jones proteins in urine.

What are Reed-Sternberg cells and their significance?

Owl-eyed cells pathognomonic for Hodgkin lymphoma; EBV association; diagnosed by excisional lymph node biopsy; treated with chemotherapy ± radiation; generally favorable prognosis.

How can you differentiate TTP from DIC on labs and presentation?

TTP: normal coagulation tests (INR, aPTT); schistocytes; thrombocytopenia; fever and neurologic symptoms; treat with emergent plasmapheresis. DIC: prolonged INR and aPTT, low fibrinogen, elevated D-dimer; treat underlying cause.

What is a postpartum TTP scenario and how does it help differentiate from DIC?

Postpartum patient with fever, neuro changes (forgetting baby’s name), thrombocytopenia; normal coagulation tests suggests TTP rather than DIC.

Which tumor markers correspond to specific cancers?

CA 19-9 — pancreatic/biliary; CA-125 — ovarian; AFP — liver/germ cell tumors; beta-hCG — testicular; CEA — colon/lung/breast; PSA — prostate; chromogranin A — neuroendocrine tumors.