Hematology Flashcards

Question

What are the classic causes of microcytic, normocytic, and macrocytic anemia? Which of these tends to have an inappropriately low reticulocyte count?

Answer 1

* **Elevated lactate dehydrogenase** (LDH) * **Elevated bilirubin** (unconjugated + conjugated if the liver is functioning) * **Jaundice** * **Low or absent haptoglobin** (intravascular hemolysis only) * **Urobilinogen, bilirubin, and hemoglobin in urine** (only conjugated bilirubin shows up in the urine, and hemoglobin shows up in the urine only when haptoglobin has been saturated, as in brisk intravascular hemolysis) * **Pigmented gallstones or history of cholecystectomy** (usually at a young age)

Answer 2

Iron deficiency anemia

Answer 3

infants: if given cow's milk before 1 year of age (due to GI bleed) women of reproductive age: menstrual blood loss, pregnancy, lactation patients \> 40: colon cancer (causing chronic, asymptomatic blood loss)

Answer 4

low iron and low ferritin levels, elevated total iron-binding capacity (TIBC; also known as transferrin), and low TIBC saturation. Rare patients may develop a craving for ice or dirt (pica)

Answer 5

A triad: **esophageal web** resulting in **dysphagia**; **iron deficiency anemia**; and **glossitis**

Answer 6

First you must determine the cause. * In a menstruating woman, a presumptive diagnosis of menstrual blood loss is often made. * In patients older than 40 years, be sure to test the stool for occult blood and strongly consider colonoscopy to detect occult colon cancer. * Postmenopausal vaginal bleeding may also cause anemia and warrants screening for gynecologic cancer. Treat with **iron supplements for 3 to 6 months** in uncomplicated cases to replete body iron stores.

Answer 7

* alcoholics (poor intake) * pregnant women (increased need) * poor diet (e.g., tea and toast) * methotrexate * prolonged therapy with trimethoprim-sulfamethoxazole * anticonvulsant therapy (especially phenytoin) * malabsorption Peripheral blood smears * macrocytes * hypersegmented neutrophils with **no** neurologic symptoms or signs * low folate levels in serum or RBCs Treat with oral folate.

Answer 8

**Pernicious anemia** - caused by antiparietal cell antibodies (most common) * Remember B12 absorption depends on intrinsic factor, which is secreted by parietal cells * B12 deficiency results in megaloblastic anemia * Achlorhydria is also present in pernicious anemia - remember that parietal cells secrete HCl as well Others: Gastrectomy, terminal ileum resection or disease (e.g., Crohn disease), strict vegan diet, chronic pancreatitis, and Diphyllobothrium latum (fish tapeworm)

Answer 9

patients have neurologic ∆s (loss of sensation and position sense, paresthesias, ataxia, spasticity, hyperreflexia, positive Babinski sign, dementia) due to degeneration of DCML peripheral blood smear: macrocytes, hypersegmented neutrophils Diagnosis: low serum B12 levels, (+) anti-intrinsic factor if pernicious anemia is the cause

Answer 10

Vitamin B12 supplements, usually given IM PO doses may have erratic absorption, so it may be best utilized after levels have been normalized via the parenteral route. Supplementation may be required for life.

Answer 11

**iron levels are** * low in iron deficiency anemia * normal in thalassemia Both cause microcytic, hypochromic anemia

Answer 12

Patients with **alpha** thalassemia are symptomatic at birth or die in utero (fetal hydrops), * 4 gene loci for alpha chain Patients with **beta** thalassemia are not symptomatic until 6 months of age. * 2 gene loci for beta chain dx: **hemoglobin electrophoresis** trmt: * minor thalassemia: no treatment because these patients are often asymptomatic as they are used to living with a lower level of Hg * major thalassemia: transfusions, iron chelation therapy to prevent secondary hemochromatosis

Answer 13

peripheral smear and African American race; usually have a **high percentage of reticulocytes** (8%-20%).

Answer 14

* Aplastic crises (caused by parvovirus B19 infection) * Bone pain (due toinfarcts; the classic example is *avascular necrosis of the femoral head*) * Dactylitis (also known as hand-foot syndrome, seen in children) * Renal papillary necrosis * Splenic sequestration crisis * Autosplenectomy (increased infections with encapsulated bugs such as Pneumococcus, Haemophilus, and Neisseria species) * Acute chest syndrome (mimics pneumonia) * Pigment cholelithiasis * Priapism * Stroke

Answer 15

hemoglobin electrophoresis Sickle cell trmt: * prophylactic penicillin until at least 5 years of age and perhaps longer, beginning as soon as the diagnosis is made. * Proper vaccinations: pneumococcal, meningococcal, and H. influenzae, yearly influenza vaccination. * folate supplementation * early treatment of infections * proper hydration Sickle cell crisis * O2 * IVF * analgesics * transfusions if symptoms/findings are severe

Answer 16

Remember that immediately after blood loss the hemoglobin may be normal; it **takes at least 3 to 4 hours, often more, for reequilibration** to occur**.** Instead, look for signs of hypovolemic shock: **obvious bleeding; pale, cold skin; tachycardia;** and **hypotension**. Consider internal hemorrhage in the setting of trauma and abdomi- nal aortic aneurysm in patients with a pulsatile abdominal mass. Treatment: transfuse if indicated, even with a normal hemoglobin in the acute setting.

Answer 17

* **Lupus erythematosus** or medications that cause lupus-like syndromes **(procainamide, hydralazine, and isoniazid)** * **Drugs** (the classic example is methyldopa, but penicillins, cephalosporins, sulfa drugs, and quinidine also have been implicated) * **Leukemia** or **lymphoma** * **Infection** (the classic examples are mycoplasmosis, Epstein-Barr virus, and syphilis)

Answer 18

**Coombs test** is positive in most autoimmune anemias. You also may see spherocytes on peripheral smear because of incomplete macrophage destruction (extravascular hemolysis) of RBCs.

Answer 19

clues: * basophilic stippling on peripheral smear * elevated free erythrocyte protoporphyrin or lead level * causes a **hypochromic, microcytic anemia** * almost always in a **child that lives in an old, run down building** Acute symptoms: vomiting, ataxia, colicky abdominal pain, irritability (aggressive behavior, behavioral regression), and encephalopathy, cerebral edema, or seizures

Answer 20

True. ## Footnote Screening all asymptomatic children with a serum lead level at 1 - 2 years old, regardless of risk, is becoming controversial. **However,** **screening should start at 6 months** **in children with risk factors, because chronic low-level exposure may lead to permanent neurologic sequelae.** risk factors: pica (especially paint chips and dust in old buildings that may have lead paint), residence in an old or neglected building, and/or residence near or family members who work at a lead-smelting or battery-recycling plant.

Answer 21

decrease exposure to source (best strategy) lead chelation therapy, if needed * succimer in children * dimercaprol in adults * in severe cases, use dimercaprol + EDTA for children or adults.

Answer 22

classic description: **microcytic, hypochromic anemia** with **increased or normal iron, ferritin, and total iron-binding capacity (transferrin).** Look for **polychromatophilic stippling** and the **classic “ringed sideroblast”** in the bone marrow Sideroblastic anemia may be related to **myelodysplasia or blood dyscrasias**. Treatment: **supportive**; in rare cases, the anemia responds to **pyridoxine/B6**. Do _not_ give iron.

Answer 23

First, look for the presence of a disease that causes chronic inflammation (e.g., rheumatoid arthritis, lupus erythematosus, cancer, tuberculosis). Findings: **normocytic (early) or microcytic (late) anemia** Labs: **Low** serum iron and total iron-binding capacity; therefore % saturation may be near normal. **Elevated** serum ferritin (ferritin is an acute-phase reactant) Treatment: Treat underlying disorder. Do _not_ give iron.

Answer 24

* Normochromic, normocytic anemia * spherocytes on peripheral smear * (+) family history (autosomal dominant) * splenomegaly * (+) osmotic fragility test * increased mean corpuscular hemoglobin concentration (the only occasion when this RBC index is useful for the Step 2 examination). Treatment: splenectomy

Answer 25

**Normocytic, normochromic anemia** with **decreased reticulocyte count** develops in all patients with chronic renal failure because of decreased erythropoietin production. Treatment: **EPO**, if necessary

Answer 26

Although aplastic anemia may be idiopathic, on the Step 2 examination watch for * **chemotherapy** * **radiation** * **malignancy affecting the bone marrow (especially leukemias)** * **benzene** * **implicated medications (chloramphenicol, carbamazepine, sulfa drugs, zidovudine, gold)** Labs: decreased WBC and platelets. Treat: * first stop any possible causative meds * then try **antithymocyte globulin, colony-stimulating factors** (EPO, sargramostim, filgrastim, pegfilgrastim), or **bone marrow transplant**

Answer 27

caused by a **space-occupying lesion in the bone marrow** (malignant invasion that destroys bone marrow, myelodysplasia, myelofibrosis) Peripheral smear: marked anisocytosis (different size), poikilocytosis (different shape), nucleated RBCs, giant and/or bizarre-looking platelets, and teardrop-shaped RBCs. Diagnosis: bone marrow biopsy may reveal no cells (“dry tap” if the marrow is fibrotic) or malignant-looking cells.

Answer 28

* **X-linked recessive, affects males** * most common in **blacks** + **Mediterraneans** * usually sudden hemolysis or anemia after exposure to **fava beans** or certain drugs **(antimalarials, salicylates, sulfa drugs**) or after **infection** * peripheral blood smear: **Heinz bodies and “bite cells”** * **diagnosis: RBC enzyme assay,** which should not be done immediately after hemolysis because of the potential for a false-negative result (all of the older RBCs have already been destroyed, and the younger RBCs are not affected in most patients) * Treat with avoidance of precipitating foods and medications; discon- tinue the triggering medication first.

Answer 29

* Endocrine failure (especially pituitary and thyroid; look for endocrine symptoms) * Mechanical heart valves (hemolyzed RBCs) * DIC, TTP, and HUS (schistocytes and RBC fragments on smear and other appropriate findings) * Hemoglobinopathies (hemoglobin C and E varieties are fairly common) * Paroxysmal nocturnal or cold hemoglobinuria * Clostridium perfringens infection, malaria, and babesiosis (cause intravascular hemolysis and fever) * Hypersplenism (associated with splenomegaly and often with low platelets and white blood cells)

Answer 30

when Hg \< 7 g/dL or if patient is symptomatic

Answer 31

* **Whole blood**: Used for rapid, massive blood loss or exchange transfusions (poisoning, thrombotic thrombocytopenic purpura). * **Packed red blood cells**: Used for routine transfusions. * **Washed red blood cells:** Free of traces of plasma, white cells, and platelets; *good in IgA deficiency* as well as for allergic or previously sensitized patients. * **Platelets**: Given for symptomatic thrombocytopenia (usually \< 10,000/μL). * **Granulocytes**: Used on rare occasions for neutropenia. * **Fresh frozen plasma**: Contains all clotting factors; used for bleeding diathesis when vitamin K will take too long to take effect (e.g., DIC, severe warfarin poisoning) or when vitamin K will not work (liver failure). * **Cryoprecipitate**: Contains fibrinogen and factor VIII; used in hemophilia, von Willebrand disease, and DIC.

Answer 32

laboratory error **Type O negative** blood can be used to avoid a reaction when you cannot wait for blood typing or when the blood bank does not have the patient's blood type.

Answer 33

Look for * **febrile reaction** (chills, fever, headache, back pain) from antibodies to WBC * **hemolytic reaction** (anxiety or discomfort, dyspnea, chest pain, shock, jaundice) from antibodies to RBCs * **allergic reaction** (e.g., urticaria, edema, dizziness, dyspnea, wheezing, anaphylaxis) to an unknown component in donor serum * **Oliguria** may be an associated finding

Answer 34

The first step is to stop the transfusion. If oliguria is present, treat with IV fluids and diuresis (mannitol or furosemide).

Answer 35

* **blood transfusion reaction** (described in another card) * **infection** (usually viral such as hepatitis B and C, HIV, CMV) * **hyperkalemia** (from hemolysis) * **bleeding diathesis** may occur with large transfusions (\> 5 U of packed RBCs) due to dilutional thrombocytopenia and citrate (a blood preservative and calcium chelator that prevents clotting). Look for oozing from puncture or IV sites.

Answer 36

* pregnancy and obstetric complications (roughly 50% of cases) * malignancy (33%) * sepsis * trauma (especially head trauma, prostate surgery, and snake bites)

Answer 37

DIC usually manifests with **bleeding diathesis** but may have **thrombotic tendencies**. Look for * classic **oozing or bleeding from puncture and IV sites** * **prolonged PT/PTT/BT** * ****DIC is the only disorder on the Step 2 examination that prolongs all three tests. * (+) D-dimers * increased fibrin degradation products * thrombocytopenia * decreased fibrin * decreased clotting factors (including factor VIII, which is normal in hepatic necrosis). Treat the underlying cause (evacuate the uterus, give antibiotics), **fresh frozen plasma** or, in rare cases, **heparin** (only if thrombosis occurs).

Answer 38

* Allergic or atopic diseases (allergic rhinitis, asthma, allergic bronchopulmonary aspergillosis, eczema, urticaria, atopic dermatitis, milk-protein allergy, drug reactions) * Parasitic infections * Fungal infections * HIV infection * Malignancies (lymphoma, leukemia, lung cancer, gastric cancer, pancreatic cancer, colon cancer, ovarian cancer) * Connective tissue/autoimmune diseases (Churg-Strauss vasculitis, rheumatoid arthritis, lupus, scleroderma, eosinophilic fasciitis, Dressler syndrome, IBD) * Granulomatous disorders (sarcoidosis) * Skin disorders (psoriasis, pemphigus) * Immune disorders (Wiskott-Aldrich syndrome, hyper-IgE syndrome, IgA deficiency, thymoma) * Adrenal insufficiency * Pulmonary eosinophilia (Löffler syndrome) * Cirrhosis * Atheroembolic disease * Familial eosinophilia * Eosinophilia-myalgia syndrome (from using L-tryptophan)

Answer 39

Allergies or neoplasm/blood dyscrasia.

Answer 40

True. Lupus anticoagulant may cause **prolonged PTT,** but patients have a tendency toward **thrombosis**. Look for: **associated lupus symptoms, (+) VDRL or (+) RPR****,**or**a history of miscarriages**

Answer 41

Genetic causes: * factor V Leiden mutation (or activated protein C resistance) * prothrombin G20210A mutation * hyperhomocysteinemia\* * elevated factor VIII level * deficiencies in protein C, protein S, or antithrombin III Acquired causes * antiphospholipid syndrome (lupus anticoagulant and anticardiolipin antibody) * hyperhomocysteinemia\* * pregnancy * cancer * estrogen-containing medications Note that hyperhomocysteinemia can be genetic or acquired. Suspect these conditions when recurrent clots develop or when a clot develops in the absence of risk factors for clot development. All are treated with **anticoagulant therapy** to prevent DVT and PEs.

Answer 42

* PT measures the function of the extrinsic clotting pathway (prolonged by warfarin) * activated PTT measures the function of the intrinsic clotting pathway (prolonged by heparin) * BT measures platelet function (prolonged by aspirin).

Answer 43

Common causes of thrombocytopenia include: * purpura (idiopathic or thrombotic) * hemolytic uremic syndrome * DIC * HIV * splenic sequestration * heparin (including heparin-induced thrombocytopenia; treat by first stopping heparin) * medications (quinidine and sulfa drugs) * autoimmune disease * alcohol Bleeding from thrombocytopenia is in the form of **petechiae, nose bleeds, and easy bruising.**

Answer 44

* **Vitamin C deficiency (scurvy)** causes bleeding similar to that seen with low platelets (splinter and gum hemorrhages, petechiae); perifollicular and subperiosteal hemorrhages are unique to scurvy. Patients have a poor dietary history (the classic example is hot dogs and soda or tea and toast), myalgias and arthralgias, and capillary fragility (bleeding is caused by collagen problems in the ves- sels). * Treat with oral vitamin C * **Uremia** (results in platelet dysfunction) * **Inherited connective tissue disorders** (Ehlers-Danlos syndrome, Marfan syndrome) * **Chronic corticosteroid use** (causes capillary fragility)