What should you do if the WBC count is too high or too low?
Order a WBC differential (super important—do this before you call a hematology consult)
- This will tell you the distribution and number of the different kinds of WBCs.
- An elevation of a line of WBCs can be malignant (leukemia) or reactive (and sometimes reactive to a different malignancy that is NOT a leukemia)
CML is a disease characterised by an elevation in _____ count, caused by an abnormal ____ in the bone marrow.
CML is a disease characterised by an elevation in neutrophil count, caused by an abnormal clone in the bone marrow.
(Remember P vera can also lead to an elevation in neutrophil count)
What can cause an elevated neutrophil count?
•CML (here, the neutrophils are made by an abnormal clone in the bone marrow). Also P vera.
•Physiologic - exercise, pregnancy, lactation, neonates
•Acute infections
•Acute inflammation
- Acute hemorrhage
- Non hematologic malignancies
- Post-splenectomy
- Drugs: corticosteroids, G-CSF, lithium
- Misc: seizures, electric shock, post-splenectomy, Leukocyte Adhesion Deficiency (they like to ask this one on boards)
- Smoking is the most common cause of a slightly elevated neutrophil count
How is the neutrophil count affected by corticosteroids?
Elevates neutrophil count.
Most neutrophils are on in the periphery on the margins of the tissues. Steroids make them let go and release into the bloodstream - looks like an elevation in total body neutrophil count, but it’s actually just more in the blood vs. on the tissues.
This also makes the neutrophils a little less effective at fighting infections.
_____ is the most common cause of an increased neutrophil count
Smoking
Leukocyte Adhesion Deficiency is characterized by a(n) ____ (increase/decrease) in neutrophil count
increase
What can cause a low neutrophil count?
•Physiologic - in African-Americans
•Drugs - esp. remember anti-psychotics, anti-epileptics, anti-thyroid, and some antibiotics
•Chemotherapeutic agents
- Infections: viral, overwhelming bacterial sepsis, TB, fungal
- Immune - lupus, rheumatoid arthritis
- Familial
- Hypothyroidism, hypopituitarism
Define agranulocytosis:
This is the complete or near-complete absence of neutrophils in the peripheral blood, with a normal platelet count and hemoglobin.
How do patients develop agranulocytosis?
•Almost always drug-induced:
- Clozapine (Clozaril®) (and other newer antipsychotics)
- Propythiouracil (antithyroid)
- Anti-convulsants
- Sulfa and chloramphenicol antibiotics
- Levamisol-contaminated cocaine
- Causes severe necrotizing ulcers in the mouth and throat
- Severe risk for life-threatening infection
What is the differential diagnosis for elevated eosinophil count?
“NAACP”:
- Neoplasm,
- Allergy/asthma,
- Addison’s disease, Athero-embolic disease
- Collagen vascular disease
- Parasites
What is Addison’s Disease?
Addison’s disease is a lack of endogenously produced corticosteroids, which normally kill eosinophils. Thus your eosinophil count rises.
Differential diagnosis of Basophilia:
•Hypersensitivity reactions
•Myeloproliferative disorders
•Thyroid disease
Differential diagnosis of lymphocytosis:
•Viral infections
•Bacterial infections - whooping cough (pertussis), TB, syphilis, brucellosis
•Chronic Lymphocytic Leukemia (CLL)
•Lymphomas and Waldenstrom’s macroglobulinemia
Differential diagnosis of Lymphopenia:
•Immunodeficiencies, including HIV/AIDS
•Immunosuppresive drugs, including corticosteroids
•Lymphomas
•Granulomatous diseases, including sarcoid, TB
•Alcoholism, malnutrition, zinc deficiency
Differential diagnosis of monocytosis:
- Bacterial infex: TB, syphilis, subacute bacterial endocarditis, typhoid, brucellosis
- Protozoal infex: malaria
- Rickettsial infex: RMSF, typhus
•Myelodysplastic syndromes
- Leukemias
- Inflammatory bowel disease
Important (4) inherited neutrophil abnormalities:
- Leukocyte Adhesion Deficiency
- Chronic Granulomatous Disease
- Myeloperoxidase Deficiency
- Chediak Higashi Syndrome
Acquired defects in neutrophil function:
•Corticosteroid Use
•Alcoholism
•Leukemias
•Myelodysplasia
•Myeloproliferative disorders
(ALL GREEN)
