TOC  | D-Dx |  HEME     

Abnormal CBC Differential Diagnosis                        REF: Outlines of Clinical Medicine 2007  

• A. Neutrophilia (Leukocytosis)
• B. Neutropenia
• C. Hypereosinophilia
• D. Lymphocytosis
• E. Lymphopenia
• F. Monocytosis
• G. Thrombocythemia
• H. Thrombocytopenia
• I. Abnormal Red Blood Cell Counts

A. Neutrophilia (Leukocytosis)

1. Acute Infection
2. Chronic Inflammation (infectious or noninfectious)
3. Glucocorticoid Therapy
4. Stress Reaction
5. Leukemia
6. Smoking
7. Lithium
8. Asplenia, hyposplenism
9. Congenital
   • a. Chronic idiopathic neutrophilia
   • b. Hereditary neutrophilia
   • c. Leukocyte adhesion deficiency
   • d. Familial cold urticaria

B. Neutropenia

1. Increased Consumption

• a. Splenomegaly
• b. Felty's Syndrome
• c. Collagen Vascular Disease
• d. Drug induced autoantibodies

2. Decreased Production

• a. Aplastic Anemia (autoimmune)
• b. Fanconi Anemia
• c. Viral Infection (especially Parvovirus B19)
• d. Radiation
• e. B12, Folate deficiency
• f. Marrow Infiltration: leukemia, tumor, myelofibrosis
• g. Cyclic Neutropenia: often in blacks, less frequent in hispanics

3. Drugs

• a. Chemotherapy: nearly all cytotoxic agents
• b. Antibiotics: chloramphenicol, sulfamethoxazole, amoxicillin, oxacillin, nafcillin
• c. Antithyroid Agents: propylthiouracil, carbimazole, methimazole
• d. Antiseizure Agents: carbamazepine, felbamate
• e. NSAIDs: aspirin, indomethacin, others
• f. Clozapine
• g. Ticlopidine
• h. Ganciclovir and valganciclovir
• i. Immunological: quinidine, heparin

C. Hypereosinophilia

1. Neoplasm

2. Allergy (drugs, other) and Asthma

3. Addison's Disease

4. Collagen Vascular Disease

5. Parasitic Infection

6. Mnemonic: "NAACP"

7. Hypereosinophilic syndrome (precancerous syndrome)

D. Lymphocytosis

1. Viral Infections

• a. Infectious mononucleosis (EBV)
• b. Cytomegaloviras (CMV)
• c. Hepatitis Viruses (HAV, HBV)
• d. Mumps, Rubella, Roseola
• e. Herpesviruses: simplex and zoster (varicella)
• f. Influenza

2. Bacterial Infectious

• a. Pertussis
• b. Rickettsia
• c. Tuberculosis
• d. Syphilis
• e. Brucellosis

3. Serum Sickness

4. Drug Induced - uncommon

5. Lymphocytic leukemias

E. Lymphopenia

1. Severe combined immunodeficiency (various forms)

• a. X-linked due to mutation in gamma chain of interleukin 2 receptor
• b. JAK3 deficiency - mutation in signalling pathway
• c. Adenosine deaminase (ADA) deficiency
• d. Lymphocyte receptor gene rearrangement defects (RAG1, RAG2 gene mutations)
• e. Omenn's Syndrome (autoreactive type 2 T helper cells)
• f. Reticular Dysgenesis

2. Acute bacterial and other infections

3. HIV infection

4. Glucocorticoids

5. Chemotherapeutic agents

6. Anti-thymocyte and OKT3 antibody therapies

7. Other lymphocyte depleting therapies (CAMPATH 1H, Anti-CD20, others)

F. Monocytosis

1. Primary Causes

• a. Cyclic neutropenia
• b. Congenital agranulocytosis
• c. Congenital disorders

2. Secondary: recovery phase from neutropenia of any cause

3. Malignant Disorders

• a. Chronic myelomonocytic leukemia
• b. Acute myeloid (M5) leukemia
• c. Chronic myeloid leukemia
• d. Monosomy 7 myeloproliferative disease

G. Thrombocythemia

1. Iron Deficiency Anemia: probably the most common cause of increased platelet counts

2. Inflammation

• a. Chronic infections
• b. Neoplasia
• c. Autoimmune: inflammatory bowel disease (IBD), rheumatoid arthritis, vasculitis
• d. Granulomatous Disease: sarcoidosis, Wegener's granulomatosis

3. Infection (acute) - platelets may be thought of as "acute phase reactant"

4. Neoplasm: any cancer, especially carcinomas and lymphomas

5. Dehydration

6. Hemolysis / Hemorrhage

7. Non-functional spleen: splenectomy, splenic infarction, sickle cell disease

8. Essential Thrombocythemia: Myeloproliferative Syndrome (platelets often >10e6/µL)

H. Thrombocytopenia

1. Drugs: chemotherapy, heparin, chloramphenicol, Ticlopidine, Clozepine, H2-blockers
2. Autoimmune :  a. Previously called idiopathic    b. May follow viral infection
3. Splenomegaly: liver failure, malignancy, infection
4. Viral: follows infection. ? Autoimmune. Associated with CMV, HIV
5. Isoimmune: in neonates, mother makes anti-platelet antibody
6. Neoplastic: infiltration of bone marrow prevents platelet development
7. Aplastic Anemia: pancytopenia; viral, idiopathic, autoimmune, chloramphenicol
8. Thrombotic thrombocytopenic purpura (TTP): with hemolysis, fever, mental status changes
9. Disseminated intravascular coagulopathy (DIC): consumptive coagulopathy
10. HIV Related
11. HELLP Syndrome: Follows pregnancy. Low platelets
12. Hereditary Disorders

I. Abnormal Red Blood Cell Counts

1. Anemia

2. Polycythemia

    2007