Hematology

1. Hematologic System Overview

The hematologic system comprises bone marrow, blood, spleen, liver, lymph nodes, and thymus gland.

Bone Marrow

• Red marrow: functional, carries out hematopoiesis (ribs, sternum, iliac crest, vertebrae, flat bones)
• Yellow marrow: red marrow that has changed to fat (long bones)
• All blood cells start as stem cells in bone marrow

Blood Composition

• 55% plasma, 45% blood cells
• Hematocrit (PCV): portion of blood composed of RBCs — M: 40–52%, F: 36–48%

Plasma

• Contains serum proteins: total protein 6–8 g/dL
• Albumin 3.5–5.5 g/dL; Globulin 2.0–3.5 g/dL (Alpha, Beta, Gamma); Fibrinogen; Prothrombin

Spleen

• Stores ~200 mL blood; important in phagocytosis & antibody production
• Splenectomy → immunosuppression in children; functions taken over by reticuloendothelial system in adults
• Can enlarge in sickle cell anemia, infectious mononucleosis

Liver

• Kupffer cells part of reticuloendothelial system; liver produces clotting factors

2. Blood Cells & Lab Interpretation

Complete Blood Count (CBC)

WBC Differential

• Granulocytes: Neutrophil (short-term phagocytosis, ↑ bacterial infection), Eosinophil (↑ allergy), Basophil (↑ inflammation from allergies)
• Agranulocytes: Lymphocyte (immune cells, ↑ viral infection; includes B cells, T cells — CD4 normal 500–1200/mm³), Monocyte (long-term phagocytosis)
• ANC (Absolute Neutrophil Count): ANC < 500 = neutropenia (high infection risk); ANC > 2000 = risk category 0

Coagulation Panel

3. Anemias Overview

4. Iron Deficiency Anemia

Microcytic, hypochromic anemia from lack of iron.

Causes

• Inadequate intake, poor absorption, GI bleed, excess menstrual bleeding
• Partial/complete gastrectomy; blood-sucking parasites; peak in women 15–45 and pregnancy

Findings

• Pallor, fatigue, weakness, dizziness, dyspnea, palpitations, cold sensitivity
• Stomatitis, brittle hair & nails

Diagnosis

• ↓ Hgb & Hct; ↓ serum iron (normal 50–150 mcg/dL); ↓ serum ferritin (normal 20–200 mcg/L)
• Hemosiderin absent from bone marrow; ↓ reticulocyte count

Management

• Diet: dark green leafy vegetables, dried fruit, whole grains, red meat, liver, egg yolk
• Oral iron: Ferrous sulfate (Feosol), Ferrous gluconate — give on empty stomach with vitamin C / OJ; liquid iron via straw; S/E: constipation, dark/tarry stool
• IM iron: Iron Dextran (Imferon) — Z-track injection, do not aspirate, do not massage; S/E: sterile abscess, lymphadenitis, anaphylaxis

5. Pernicious (B₁₂ Deficiency) Anemia

Chronic progressive macrocytic/megaloblastic anemia. Higher incidence in blue-eyed / Scandinavian descendants.

Causes

• Deficiency of intrinsic factor (IF) — produced by parietal cells in stomach
• Atrophy of gastric mucosa (hereditary or autoimmune); post-gastrectomy
• Dietary deficiency (vegan vegetarian)

B₁₂ Functions & Deficiency Findings

• RBC maturation → anemia (pallor, weakness, palpitation, dyspnea)
• GI tract cells → sore mouth, beefy red tongue, weight loss, dyspepsia, constipation/diarrhea
• CNS & PNS → paresthesia, paralysis, depression, psychosis

Diagnosis

• Schilling Test: measures absorption of radioactive B₁₂ before/after parenteral IF
• Normal absorption ≥ 10% over 24 hr; < 10% = pernicious anemia
• Gastric analysis: ↓ free HCl; blood smear: oval macrocytic RBCs; bone marrow: ↑ megaloblasts

Management

• Monthly B₁₂ injections IM (lifelong)
• Iron & folic acid supplements; blood transfusion in severe cases
• Diet: animal sources (meat, milk, fish, eggs), soybean, oral B₁₂ supplements
• Nursing: balanced diet; if mouth sores → avoid spicy/hot food, soft mouth care; bed rest for severe anemia

6. Aplastic Anemia

Bone marrow depression → pancytopenia (↓ all cell lines).

Causes

• Idiopathic; secondary to benzene, chloramphenicol, chemotherapy, radiation

Findings

• Anemia (fatigue, pallor), infection risk (neutropenia), bleeding risk (thrombocytopenia)

Diagnosis

• Bone marrow biopsy → fatty replacement of marrow

Management

• Bone marrow transplant; blood transfusions; colony-stimulating factors
• Nursing: neutropenic precautions, meticulous mouth care; minimize bleeding risk (soft toothbrush, no dental floss, electric razor, hematest urine/stool; avoid IM injections); high-protein high-vitamin diet, rest

7. Hemolytic Anemias

Sickle Cell Anemia

Most common genetic disorder in U.S.; trait in 10% of African-Americans. Autosomal recessive → defective HgbS → crescent-shaped, inflexible RBCs (life span 6–20 days).

Crisis Types

• Vaso-occlusive (thrombocytic): sickled cells block microcirculation → severe pain, hypoxia
• Splenic (sequestration): blood pools in spleen → hypovolemia, shock; splenectomy may be needed
• Aplastic: bone marrow hyperplasia → pathological fractures

Findings

• Dactylitis (hand-foot syndrome), abdominal colic, delayed G&D, frequent infections, leg ulcers, CVA, priapism, hemolytic anemia & jaundice, heart/renal failure from hemosiderosis

Diagnosis

• Hgb 6–9 g/dL, sickledex test, Hgb electrophoresis

Management

• Hydration (oral & IV), O₂, narcotic analgesics (morphine — Demerol contraindicated), aspirin contraindicated
• Hydroxyurea (↓ HgbS), folic acid, antibiotics, bed rest, splenectomy
• Nursing: hydration & oxygenation, avoid tight clothing, keep extremities warm, avoid infection, genetic counseling, avoid overexposure to sun/heat, avoid unpressurized planes

Beta-Thalassemia (Cooley's Anemia)

• Autosomal recessive; defect in globin molecule → thin fragile target cells; Mediterranean region
• Minor: heterozygous, mild anemia; Major: homozygous, severe anemia, transfusion-dependent
• Findings: severe anemia, impaired G&D, splenomegaly/hepatomegaly, jaundice, cholelithiasis
• Management: blood transfusions, Deferoxamine (Desferal) for iron overload, bone marrow transplant, folic acid

8. Coagulation Disorders

Hemophilia

• Hemophilia A: Factor VIII deficiency (sex-linked); B (Christmas): Factor IX deficiency (sex-linked); C: Factor XI deficiency (autosomal recessive)
• Findings: prolonged bleeding after minor injury, bruising/hematoma, hemarthrosis (bleeding into joints → contractures, degeneration)
• Diagnosis: normal platelets, ↓ clotting factors, prolonged clotting time
• Management: manual pressure 15 min, hemostatic agents (topical epinephrine, fibrin foam, ADH), cryoprecipitate (thaw slowly, infuse immediately), codeine for pain (avoid aspirin, Motrin, Percodan)
• Hemarthrosis care: immobilize, elevate, avoid weight bearing 48 hr, ROM exercises as tolerated

Idiopathic Thrombocytopenic Purpura (ITP)

• Autoimmune → ↑ platelet destruction; platelets < 100,000/mm³
• Often preceded by viral illness; spontaneous bleeding into CNS/muscle/joint if < 20,000/mm³
• 80% children & 20% adults recover spontaneously
• Findings: petechiae, purpura, ecchymosis, epistaxis, mucosal bleeding, anemia
• Management: immunosuppressives, immunoglobulins, plasmapheresis, platelet transfusion, splenectomy
• Nursing: prevent bruising, ice compress, elevate bleeding part, avoid IM meds, avoid aspirin (Tylenol preferred), soft swab mouth care, stool softeners, padding, avoid contact sports

Disseminated Intravascular Coagulation (DIC)

• Abnormal clotting cascade activation → widespread microthrombi → consumption of clotting factors → hemorrhage
• Causes: sepsis, trauma, obstetric complications, malignancy, shock
• Findings: bleeding from multiple sites (petechiae, ecchymosis, oozing from IV sites), organ dysfunction from microthrombi
• Diagnosis: ↑ PT/PTT, ↓ platelets, ↓ fibrinogen, ↑ D-dimer, ↑ FDP
• Management: treat underlying cause, replace clotting factors (FFP, cryoprecipitate, platelets), heparin in some cases

Von Willebrand Disease

• Deficiency or defect of von Willebrand factor (vWF) — needed for platelet adhesion
• Findings: easy bruising, epistaxis, menorrhagia, prolonged bleeding time despite normal platelet count
• Management: DDAVP (desmopressin) to release vWF from endothelial stores; cryoprecipitate

9. Transfusion Therapy

Blood Products

Nursing Care for Transfusion

• Confirm order & signed consent; consider religious restrictions
• Ensure 18–19 gauge IV catheter; use special transfusion set with filter
• Prime tubing ONLY with NS (no dextrose — causes hemolysis)
• Two RNs verify patient ID, product, and blood bag data
• Take baseline VS; pre-medicate with Tylenol/Benadryl if ordered
• Start slowly at 2 mL/min; stay with client first 15 min; VS q15min × 1 hr then q1h
• Transport blood for one client at a time; administer within 20–30 min of arrival

Transfusion Reactions

10. NCLEX Priorities

• Transfusion reaction — first action: STOP the transfusion immediately, maintain IV access with NS
• Hemolytic reaction: most dangerous — back pain, fever, shock, renal failure; return blood bag & tubing to lab
• PRBC administration: only NS in tubing; 18–19 gauge IV; infuse over 2–4 hr; stay with client first 15 min
• Neutropenic precautions (ANC < 500): private room, no fresh flowers/fruit, avoid visitors with infections, meticulous hand hygiene
• Iron administration (IM): Z-track, do not aspirate, do not massage; use separate needles for withdrawal & injection
• Pernicious anemia: lifelong monthly B₁₂ injections; monitor for CNS symptoms (paresthesia, paralysis, depression)
• Sickle cell crisis: priority is hydration & oxygenation; morphine for pain; avoid Demerol; avoid ASA
• Aplastic anemia: pancytopenia management = infection precautions + bleeding precautions + fatigue management
• Hemophilia: apply pressure 15 min; avoid ASA; cryoprecipitate for Factor VIII replacement; avoid IM injections
• ITP: bleeding precautions; soft toothbrush; no rectal temps; avoid IM; Tylenol not aspirin; prevent injury
• DIC: treat underlying cause; replace clotting factors (FFP, cryoprecipitate, platelets); monitor for both bleeding & thrombosis
• Schilling test: measures B₁₂ absorption; normal ≥ 10% over 24 hr urine collection