12.4 Hematologic Disorders: Anemias (Microcytic, Normocytic, Macrocytic), Leukopenia & Coagulopathies

Hematologic Disorders: Anemias, Leukopenia & Coagulopathies

Hematologic abnormalities are encountered daily in adult and geriatric primary care, ranging from asymptomatic mild laboratory anomalies discovered on routine screening to fulminant, life-threatening oncologic and thrombohemorrhagic emergencies. For the Adult-Gerontology Primary Care Nurse Practitioner (AGPCNP), clinical mastery requires systematic interrogation of complete blood count (CBC) indices, peripheral blood smears, iron kinetics, bone marrow proliferative responses, and the coagulation cascade.

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1. Algorithmic Diagnostic Approach to Anemias

Anemia is defined by the World Health Organization (WHO) as Hemoglobin (Hb) $<13.0\text{ g/dL}$ in adult men and $<12.0\text{ g/dL}$ in non-pregnant adult women. Initial classification relies on the Mean Corpuscular Volume (MCV) and the bone marrow's regenerative capacity measured by the Reticulocyte Production Index (RPI).

+---------------------------------------------------------------------------------------------------+
|                                ALGORITHMIC CLASSIFICATION OF ANEMIAS                              |
|                                                                                                   |
|   [INITIAL CBC: HEMOGLOBIN / HEMATOCRIT REDUCED]                                                  |
|                                  |                                                                |
|                                  v                                                                |
|   [EVALUATE MEAN CORPUSCULAR VOLUME (MCV)]                                                        |
|         /                        |                        \                                       |
|        v                         v                         v                                      |
|   MICROCYTIC (MCV <80 fL)   NORMO CYTIC (MCV 80-100 fL)   MACROCYTIC (MCV >100 fL)                |
|   * Differential (TAILS):   * CHECK RETICULOCYTE INDEX:   * EVALUATE PERIPHERAL SMEAR:            |
|     - Thalassemia             - RPI >2% (Hyperproliferative): - Megaloblastic (Hypersegmented      |
|     - Anemia of Chronic         * Hemolysis (Warm AIHA,         neutrophils + oval macrocytes):   |
|       Disease (ACD)               Cold agglutinin, G6PD,        * Vitamin B12 Deficiency          |
|     - Iron Deficiency             Sickle cell, MAHA/TTP)        * Folate (B9) Deficiency          |
|     - Lead Poisoning            * Acute blood hemorrhage      - Non-Megaloblastic (Round macrocytes)|
|     - Sideroblastic           - RPI <2% (Hypoproliferative):    * Chronic Alcoholism / Cirrhosis  |
|                                 * Early Iron / B12 / Folate     * Hypothyroidism                  |
|                                 * Anemia of Chronic Disease     * Myelodysplastic Syndromes (MDS) |
|                                 * Chronic Kidney Dis (Low EPO)  * Reticulocytosis                 |
|                                 * Aplastic Anemia / Marrow inv  * Medications (Hydroxyurea)       |
+---------------------------------------------------------------------------------------------------+

The Reticulocyte Production Index (RPI)

Raw reticulocyte percentages overestimate marrow response in anemia because the total RBC pool is reduced. The AGPCNP calculates the Corrected Reticulocyte Count and RPI:

$\text{Corrected Reticulocyte Count (\%)} = \text{Observed Reticulocyte \%} \times \left(\frac{\text{Patient's Hematocrit}}{\text{Normal Hematocrit (45)}}\right)$

$\text{Reticulocyte Production Index (RPI)} = \frac{\text{Corrected Reticulocyte Count}}{\text{Maturation Correction Factor (1.0 to 2.5 based on Hct)}}$

• RPI $>2.0%$: Adequate marrow response; indicates accelerated erythrocyte destruction (Hemolysis) or acute hemorrhage.
• RPI $<2.0%$: Inadequate hypoproliferative marrow response; indicates substrate deficiency (iron, B12, folate), lack of erythropoietin stimulation (CKD), marrow suppression/damage, or chronic inflammation.

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2. Microcytic Anemias (MCV <80 fL): Differential Diagnosis

+---------------------------------------------------------------------------------------------------+
|                         MICROCYTIC ANEMIAS: IRON KINETICS & DIFFERENTIAL                          |
|                                                                                                   |
|   PARAMETER         IRON DEFICIENCY (IDA)   THALASSEMIA TRAIT       ANEMIA CHRONIC DIS (ACD)      |
|   ---------------------------------------------------------------------------------------------   |
|   Serum Ferritin    LOW (<30 ng/mL;         NORMAL to HIGH          NORMAL to ELEVATED (acute     |
|                     <15 is diagnostic)      (normal iron stores)    phase reactant; trapped iron) |
|   Serum Iron        LOW                     NORMAL                  LOW                           |
|   TIBC              HIGH (>400 mcg/dL)      NORMAL                  LOW to NORMAL (<250 mcg/dL)   |
|   Transferrin Sat   LOW (<16% - 20%)        NORMAL                  LOW to NORMAL (15% - 25%)     |
|   RDW               HIGH (>15%; anisocytosis)NORMAL (homogeneous size)NORMAL to mildly elevated  |
|   RBC Count         LOW                     HIGH (>5.5 million/mcL; LOW to NORMAL                 |
|                                             microcytic polycythemia)                              |
|   Mentzer Index     > 13                    < 13                    Variable                      |
|   (MCV / RBC count)                                                                               |
|   Hemoglobin        Normal HbA, A2, F       Beta-Thal: HbA2 >3.5%   Normal HbA, A2, F             |
|   Electrophoresis                           Alpha-Thal: Normal                                    |
+---------------------------------------------------------------------------------------------------+

Iron Deficiency Anemia (IDA): Etiology, Clinical Findings & Management

• Etiologies:
  • Adult Males & Postmenopausal Females: Gastrointestinal blood loss until proven otherwise! Mandatory evaluation with Colonoscopy and Esophagogastroduodenoscopy (EGD) to exclude occult colorectal carcinoma, gastric adenocarcinoma, peptic ulcer disease, or angiodysplasias.
  • Premenopausal Females: Menorrhagia / abnormal uterine bleeding, pregnancy/lactation.
  • Malabsorption: Celiac disease, prior Roux-en-Y gastric bypass, Helicobacter pylori gastritis, chronic high-dose PPI use.
• Physical Signs: Pallor (conjunctival, palmar), fatigue, exertional dyspnea, koilonychia (spoon nails), angular cheilitis, atrophic glossitis, pica (compulsive craving for non-nutritive substances: pagophagia [ice], geophagia [clay/dirt], amylophagia [starch]), restless legs syndrome, and Plummer-Vinson syndrome (triad of microcytic anemia, esophageal webs with dysphagia, and atrophic glossitis).
• Pharmacological Treatment:
  • Oral Iron: Ferrous Sulfate 325 mg (65 mg elemental iron) once daily or on alternate days (alternate-day dosing enhances intestinal iron absorption by preventing hepcidin upregulation and reduces GI side effects). Take on an empty stomach with Vitamin C (ascorbic acid 500 mg) to enhance acidic absorption; avoid co-administration with calcium, antacids, PPIs, dairy, tea, or coffee. Continue oral therapy for 3 to 6 months after normalization of hemoglobin to replenish tissue ferritin stores.
  • Intravenous Iron (Ferric carboxymaltose, Iron sucrose): Indicated for oral iron intolerance, severe malabsorption (Celiac, bariatric surgery), active inflammatory bowel disease, chronic kidney disease on hemodialysis, or rapid replacement needs.

Thalassemia Syndromes

• Beta-Thalassemia Minor (Trait): Heterozygous mutation in beta-globin gene on chromosome 11. Manifests as mild microcytic anemia (Hb 10–12 g/dL) with profound microcytosis (MCV 55–75 fL), elevated RBC count ($>5.5\times 10^{12}/\text{L}$), normal RDW, and Mentzer Index $<13$. Confirmatory test: Hemoglobin Electrophoresis revealing elevated Hemoglobin $A_2$ ($>3.5%$) and elevated HbF.
• Alpha-Thalassemia Trait: Deletion of 2 alpha-globin genes on chromosome 16. Hemoglobin electrophoresis in adults is completely normal; definitive diagnosis requires alpha-globin gene DNA testing.
• Critical Board Warning: Never prescribe empiric iron therapy to patients with thalassemia trait unless co-existing iron deficiency is proven by low ferritin! Administering iron to thalassemia patients causes iatrogenic iron overload (hemosiderosis).

Anemia of Chronic Disease (ACD / Anemia of Inflammation)

• Pathogenesis: Driven by Hepcidin, a hepatic peptide upregulated by inflammatory cytokines (principally IL-6). Hepcidin binds to and degrades ferroportin (the iron efflux channel on enterocytes and reticuloendothelial macrophages), blocking intestinal iron absorption and trapping iron inside macrophage storage pools, depriving developing erythroid precursors of iron.
• Management: Treat the underlying chronic inflammatory, infectious, or malignant condition. In chronic kidney disease, administer Erythropoiesis-Stimulating Agents (ESAs: Epoetin alfa, Darbepoetin alfa) when $\text{Hb} < 10\text{ g/dL}$, maintaining target Hb between 10.0 and 11.5 g/dL (targeting $\text{Hb} > 11.5\text{ g/dL}$ increases risks of stroke, venous thromboembolism, and cardiovascular mortality). Ensure iron repletion (ferritin $>100\text{ ng/mL}$, TSAT $>20%$) before initiating ESAs.

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3. Macrocytic Anemias (MCV >100 fL): Megaloblastic vs. Non-Megaloblastic

+---------------------------------------------------------------------------------------------------+
|                         MEGALOBLASTIC ANEMIAS: BIOCHEMICAL & CLINICAL PROFILE                     |
|                                                                                                   |
|   FEATURE              VITAMIN B12 (COBALAMIN) DEFICIENCY  FOLATE (VITAMIN B9) DEFICIENCY         |
|   ---------------------------------------------------------------------------------------------   |
|   Pathophysiology      Impaired DNA synthesis; defective   Impaired DNA synthesis; defective      |
|                        conversion of homocysteine -> met   purine/thymidylate synthesis.          |
|                        and methylmalonyl-CoA -> succinyl   Stores deplete in 3 to 4 MONTHS!       |
|                        Stores last 3 to 5 YEARS!                                                  |
|                                                                                                   |
|   Common Causes        Pernicious Anemia (anti-IF/anti-    Inadequate dietary intake (alcoholism, |
|                        parietal cell Ab), Gastrectomy,     elderly tea-and-toast diet), malabsorp-|
|                        terminal ileal disease (Crohn's),   tion (Celiac), medications: METHOTREX- |
|                        Strict Vegans, METFORMIN, PPIs.     ATE, Trimethoprim, Phenytoin.          |
|                                                                                                   |
|   Neurological Signs   PRESENT & PROGRESSIVE:              ABSENT!                                |
|                        Subacute Combined Degeneration      No spinal cord or peripheral nerve     |
|                        (SCD: posterior column vibratory /  degeneration.                          |
|                        proprioception loss, spasticity,                                           |
|                        ataxia, "megaloblastic madness").                                         |
|                                                                                                   |
|   Peripheral Smear     Oval macrocytes + HYPERSEGMENTED    Oval macrocytes + HYPERSEGMENTED       |
|                        NEUTROPHILS (>=5 lobes in >=5%).    NEUTROPHILS (>=5 lobes in >=5%).       |
|                                                                                                   |
|   Methylmalonic Acid   ELEVATED (>0.4 mcmol/L)             NORMAL                                 |
|   (MMA)                                                                                           |
|                                                                                                   |
|   Homocysteine         ELEVATED                            ELEVATED                               |
|                                                                                                   |
|   First-Line Therapy   Cyanocobalamin 1000 mcg IM daily    Oral Folic Acid 1 to 5 mg PO daily.    |
|                        x 1 wk -> weekly x 4 wks -> monthly Always rule out B12 deficiency first!   |
|                        (or high-dose oral 1000-2000 mcg/d).                                       |
+---------------------------------------------------------------------------------------------------+

The Folate Trap & Neurological Risk

If a patient with occult Vitamin B12 deficiency is mistakenly treated with high-dose Folate monotherapy, the hematologic anemia will resolve because folate bypasses the enzymatic block in DNA synthesis, but the neurological degeneration (Subacute Combined Degeneration of the spinal cord) will rapidly progress to irreversible paraplegia and dementia. The AGPCNP must always verify Vitamin B12 levels before or concurrent with initiating folate therapy.

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4. Normocytic Hemolytic Anemias & Smear Morphologies

+---------------------------------------------------------------------------------------------------+
|                         HEMOLYTIC ANEMIAS: LABORATORY HALLMARKS & TAXONOMY                        |
|                                                                                                   |
|   [HALLMARKS OF ACTIVE HEMOLYSIS]                                                                 |
|   - Elevated Reticulocyte Production Index (RPI >2%)                                              |
|   - Elevated Lactate Dehydrogenase (LDH) & Elevated Indirect (Unconjugated) Bilirubin             |
|   - Decreased / Absent Serum Haptoglobin (haptoglobin binds free intravascular hemoglobin)        |
|   - Peripheral Smear Abnormalities (Schistocytes, Spherocytes, Bite cells, Target cells)           |
|                                  |                                                                |
|                                  v                                                                |
|   [DIRECT ANTIGLOBULIN TEST (DAT / COOMBS TEST)]                                                  |
|         /                                                 \                                       |
|        v                                                   v                                      |
|   DAT POSITIVE: IMMUNE-MEDIATED                       DAT NEGATIVE: NON-IMMUNE                    |
|   1. Warm AIHA (IgG mediated at 37°C):                1. Microangiopathic (MAHA / Schistocytes):  |
|      - Extravascular splenic hemolysis;                 - TTP, HUS, DIC, Mechanical valves.       |
|        Spherocytes on smear; triggered by               - High shear stress fragments RBCs.       |
|        CLL, SLE, drugs (penicillin, ceftriaxone).     2. Enzymatic Defect:                        |
|      - First-line: Oral Prednisone (1 mg/kg/day).       - G6PD Deficiency: X-linked; oxidative    |
|   2. Cold Agglutinin Disease (IgM mediated <37°C):        stress (fava beans, sulfa, dapsone);    |
|      - Intravascular/extravascular hemolysis;             Heinz bodies & BITE CELLS (degmacytes). |
|        triggered by Mycoplasma pneumoniae, EBV.       3. Hemoglobinopathy:                        |
|      - Acrocyanosis; keep patient warm; Rituximab.      - Sickle Cell Disease (HbSS): sickle cells,|
|      - (Steroids and splenectomy are INEFFECTIVE!).       Howell-Jolly bodies (autosplenectomy).  |
+---------------------------------------------------------------------------------------------------+

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5. Leukopenia, Oncologic Hematology & Multiple Myeloma

Neutropenia & Febrile Neutropenia Oncologic Protocol

• Absolute Neutrophil Count (ANC):

$\text{ANC} = \text{Total WBC} \times \left(\frac{\%\text{Segmented Neutrophils} + \%\text{Band Neutrophils}}{100}\right)$

• Severity: Mild (1000–1500/mcL), Moderate (500–1000/mcL), Severe ($<500/\text{mcL}$ or predicted nadir $<500$).
• Febrile Neutropenia Definition: Single oral temperature $\ge 38.3^\circ\text{C}$ ($101^\circ\text{F}$) or sustained $\ge 38.0^\circ\text{C}$ ($100.4^\circ\text{F}$) for $>1\text{ hour}$ in a patient with $\text{ANC} < 500/\text{mcL}$.
• Emergency Protocol: ONCOLOGIC EMERGENCY. Administer empiric, broad-spectrum, antipseudomonal monotherapy within 60 minutes of presentation: IV Cefepime (2 g q8h), Piperacillin-tazobactam (4.5 g q6h), or Meropenem (1 g q8h). Add IV Vancomycin if hemodynamic instability, central catheter infection, or pneumonia is present.

Chronic Leukemias: CLL vs. CML

+---------------------------------------------------------------------------------------------------+
|                                 CHRONIC LEUKEMIAS COMPARATIVE PROFILE                             |
|                                                                                                   |
|   FEATURE              CHRONIC LYMPHOCYTIC LEUKEMIA (CLL)  CHRONIC MYELOGENOUS LEUKEMIA (CML)     |
|   ---------------------------------------------------------------------------------------------   |
|   Epidemiology         Most common leukemia in Western     Adults age 40 - 60 years               |
|                        adults; median age 70 years         (15% of adult leukemias)               |
|   Cytogenetics         Deletions 13q14, 11q, 17p (p53)     PHILADELPHIA CHROMOSOME t(9;22)(q34;q11)|
|                                                            BCR-ABL1 fusion tyrosine kinase gene   |
|   Peripheral Smear     Absolute mature lymphocytosis       Dramatic leukocytosis (>100,000/mcL)   |
|                        (>5000/mcL) + SMUDGE CELLS          with FULL MYELOID SPECTRUM (myelocytes,|
|                        ("basket cells"); Coombs (+) AIHA.  metamyelocytes, blasts <2%, basophilia)|
|   Clinical Signs       Painless generalized lymphadenopathy,Massive splenomegaly, abdominal full- |
|                        hepatosplenomegaly, fatigue.        ness, hypermetabolic fever/sweats.     |
|   Treatment Approach   Asymptomatic early stage: WATCHFUL  Targeted TYROSINE KINASE INHIBITORS    |
|                        WAITING (active surveillance);      (TKIs: Imatinib, Dasatinib, Nilotinib).|
|                        Targeted agents: BTK inhibitors                                            |
|                        (Ibrutinib, Acalabrutinib).                                                |
+---------------------------------------------------------------------------------------------------+

Multiple Myeloma: The CRAB Diagnostic Tetrad

Clonal proliferation of malignant plasma cells in bone marrow producing monoclonal immunoglobulin ($M\text{-protein}$, most commonly IgG in 55% or IgA in 20%):

• C - Hypercalcemia: Serum calcium $>11.0\text{ mg/dL}$, caused by osteoclast-activating factors (RANKL).
• R - Renal Insufficiency: Serum creatinine $>2.0\text{ mg/dL}$, caused by toxic light-chain cast nephropathy (myeloma kidney).
• A - Anemia: Normocytic normochromic anemia ($\text{Hb} < 10\text{ g/dL}$) due to bone marrow plasma cell infiltration.
• B - Bone Lytic Lesions: "Punched-out" osteolytic lesions on skeletal survey/CT, pathological fractures, severe unremitting back pain.
• Diagnostic Workup: Serum Protein Electrophoresis (SPEP - monoclonal M-spike), Urine Protein Electrophoresis (UPEP - Bence Jones proteinuria), Serum Free Light Chain (FLC) ratio, bone marrow biopsy ($>10%$ clonal plasma cells), Rouleaux formation on peripheral blood smear (RBCs stacked like coins), and markedly elevated ESR ($>100\text{ mm/h}$).

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6. Coagulopathies, Platelet Disorders & Anticoagulation

+---------------------------------------------------------------------------------------------------+
|                         PLATELET & COAGULATION DISORDERS MATRIX                                   |
|                                                                                                   |
|   DISORDER          PATHOPHYSIOLOGY & CLINICAL SIGNS   LABORATORY FINDINGS MANAGEMENT PROTOCOL    |
|   ---------------------------------------------------------------------------------------------   |
|   Immune            Autoantibodies (IgG) against       Isolated THROMBO-   Asymptomatic & plt>30k:|
|   Thrombocytopenia  platelet GPIIb/IIIa -> splenic     CYTOPENIA (<30,000);Observe. Plt <30,000   |
|   (ITP)             destruction. Petechiae, purpura,   normal PT/INR, aPTT,or bleeding: Oral      |
|                     epistaxis, mucosal bleeding.       normal smear.       Prednisone or IVIG.    |
|                                                                                                   |
|   Heparin-Induced   IgG autoantibodies against         >=50% DROP in plt   IMMEDIATELY STOP ALL   |
|   Thrombocytopenia  HEPARIN-PF4 COMPLEX -> platelet    count 5-10 days     HEPARIN! Start non-    |
|   (HIT Type II)     activation -> PROTHROMBOTIC CRISIS!post-heparin. Anti- heparin Direct Thrombin|
|                     Venous/arterial thrombosis (DVT/PE).PF4 ELISA / SRA (+).Inhibitor (Argatroban).|
|                                                                                                   |
|   Thrombotic        Severe deficiency of ADAMTS13      Thrombocytopenia +  EMERGENT THERAPEUTIC   |
|   Thrombocytopenic  protease (<10%) -> ultra-large     MAHA (SCHISTOCYTES) PLASMA EXCHANGE (PLEX) |
|   Purpura (TTP)     vWF multimer microvascular clots.  + Normal PT and aPTT+ Corticosteroids.     |
|                     Pentad: MAHA, Plt low, Neuro signs,(rules out DIC!).   NEVER GIVE PLATELETS!  |
|                     Fever, Renal dysfunction.          ADAMTS13 <10%.                             |
|                                                                                                   |
|   Disseminated      Systemic uncontrolled activation   PROLONGED PT/INR &  Treat underlying cause;|
|   Intravascular     of coagulation -> consumptive      aPTT; Low FibrinogenCryoprecipitate (if    |
|   Coagulation (DIC) coagulopathy and lethal bleeding.  (<100 mg/dL); High  fibrinogen <100), FFP, |
|                     Triggers: Sepsis, trauma, APL.     D-Dimer; Plt low.   platelet transfusions. |
+---------------------------------------------------------------------------------------------------+

Oral Anticoagulant Monitoring & Reversal Agents

• Warfarin (Coumadin): Inhibits Vitamin K Epoxide Reductase (VKORC1), blocking synthesis of Factors II, VII, IX, X, and Proteins C and S. Monitored via PT/INR (Target INR 2.0–3.0 for non-valvular atrial fibrillation, DVT, PE; 2.5–3.5 for mechanical mitral valves). Reversal: Oral/IV Vitamin K1 (Phytonadione) + 4-Factor Prothrombin Complex Concentrate (4F-PCC / Kcentra) for life-threatening bleeding.
• Direct Oral Anticoagulants (DOACs):
  • Direct Factor Xa Inhibitors: Apixaban (Eliquis), Rivaroxaban (Xarelto), Edoxaban (Savaysa). Reversal Agent: Andexanet alfa (Andexxa).
  • Direct Thrombin (Factor IIa) Inhibitor: Dabigatran (Pradaxa). Reversal Agent: Idarucizumab (Praxbind).

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7. Board-Yield Summary & Clinical Pearls

+---------------------------------------------------------------------------------------------------+
|                                 ANCC AGPCNP CLINICAL EXAM PEARLS                                  |
|                                                                                                   |
|   - Any new, unexplained Iron Deficiency Anemia in an adult male or postmenopausal female is      |
|     Gastrointestinal Malignancy until proven otherwise! Schedule Colonoscopy and EGD.             |
|                                                                                                   |
|   - Macrocytic Anemia with Hypersegmented Neutrophils = Megaloblastic Anemia. Check both B12 and   |
|     Folate, as well as Methylmalonic Acid (MMA). Elevated MMA confirms Vitamin B12 deficiency!   |
|     Never treat B12 deficiency with Folate alone, as irreversible Subacute Combined Degeneration  |
|     of the spinal cord will progress.                                                             |
|                                                                                                   |
|   - Thalassemia Trait produces marked microcytosis (MCV 55-75) with mild anemia, high RBC count,  |
|     normal ferritin, and Mentzer Index <13. Never prescribe iron therapy to Thalassemia trait!    |
|                                                                                                   |
|   - Suspected Heparin-Induced Thrombocytopenia (HIT): Stop ALL heparin immediately and switch to  |
|     Argatroban or Fondaparinux. Never initiate Warfarin until platelet counts recover to >=150,000|
|     to prevent catastrophic warfarin-induced microvascular skin necrosis.                        |
|                                                                                                   |
|   - TTP is a medical emergency requiring immediate Therapeutic Plasma Exchange (PLEX) and        |
|     corticosteroids. Platelet transfusions are STRICTLY CONTRAINDICATED (fuels microvascular clots).|
|                                                                                                   |
|   - Multiple Myeloma CRAB Criteria: HyperCalcemia, Renal insufficiency, Anemia, Bone lytic lesions.|
|     Diagnosed with SPEP (M-spike), UPEP (Bence Jones light chains), and bone marrow biopsy.       |
+---------------------------------------------------------------------------------------------------+