WBC Flashcards
indications for a CBC
o Hemorrhage (look at hct & hgb)
o Infection (look at WBC)
o Chronic fatigue/Sudden pain
o Unknown bruising/Blood in urine
what’s included in CBC
o total WBC
o red blood cells
o Hemoglobin & hematocrit
o WBC with differentials (neutrophils, lymphocytes, monocytes, eosinophils, basophils)
function of WBC (aka leukocytes)
fight infection, react against foreign invaders (inflammation
differentiation of WBCs
o Total WBC count
o Differential- % of each type of leukocyte= 100%
* Neutrophils (70%)
* Lymphocytes (20-40%)
* Monocytes (3-8%)
* Eosinophils (1-6%)
* Basophils (0.01-0.3%)
innate immunity
body’s first defense
* Rapid, non-specific
* Pathogen associated molecular patterns (PAMPs) bind to Pattern Recognition Receptors (PRRs) immune response
* Response involves
* Granulocytes—–>Neutrophils, basophils, eosinophils
* Monocytes –> macrophages –> phagocytosis
* Activation of the complement system
adaptive immunity
based on antigen exposure
* Slower, specific, learned
* Response involves
* Lymphocytes
o T-cells (mature in the thymus)
o B-cells (mature in the bone marrow)
viral infection=
elevated lymphocytes
bacterial infection=
elevated WBCs
neutrophilia (increased neutrophil count): common causes
o Infection (typically bacterial)
o Inflammation
o Stress (physical and emotional)
o Vigorous exercise
o Cigarette Smoking
o Drugs
o Pregnancy
o Obesity
o Asplenia
o Myeloproliferative neoplasms (ie CML)
neutropenia (decreased neutrophil count): common causes
o Decreased production from the bone marrow
* Bone marrow injury/suppression
Overwhelming infection
* Bone marrow capacity exceeded by use
o Viral infection (including hepatitis, HIV, sepsis) – related to marrow injury from pathogen
o Drugs
o Radiation therapy
o B12/Folate deficiency
o Autoimmune/Idiopathic
o Lab artifact – EDTA
“Left Shift”
- More bands and less segmented cells body is sending out these immature neutrophils bc there’s often an infection
- Associate a left shift with bacterial infection
- Left shift is associated with Neutrophilia (increased neutrophils)
ANC- infection risk: formula
ANC= WBC * (% neutrophils + % bands)
degree of neutropenia correlates with risk of infection
o Mild 1.0-2.0 x 10^9/L
o Moderate 0.5 – 1.0 x 10^9/L
o Severe <0.5 x 10^9/L
red flags
o <1.0 well or febrile: Urgent referral
o 1.0-2.0 febrile – Urgent eval; well – close follow-up, if persists- to heme
* Very low ANC would suggest immunocompromise
eosinophils
- Physiologic function unknown
- Reside primarily in tissue
- Phagocytes of antigen-antibody complexes
- Seen in allergic response
- Elevated with parasitic infection
- Unlikely to be seen in bacterial and viral infections
eospinophilia (increased eosinophils)–> worms, wheezes, weird diseases
- Often found incidentally
- Allergic disorders
o Asthma, hay fever, food or drug sensitivity - Parasitic infection
o Trichinosis, hookworm, roundworm, amebiasis - Skin
o Eczema, psoriasis, dermatitis - Autoimmune
o Scleroderma - Neoplastic diseases
o Hodgkin’s disease, Chronic Myelocytic Leukemia (CML), tumors - Others…
o Eosinophilic esophagitis, eosinophilic gastritis, ulcerative colitis, pernicious anemia, excessive exercise
having LOW eosinophils is….
UNCOMMON
basophils
- As with neutrophils and eosinophils, basophils perform phagocytosis
- Seen in allergic reactions
- Can be simulated in parasitic infections
- Unlikely to be seen in bacterial in viral infections
- Contain histamine, heparin, and serotonin
o Hives - Basophilia often indicates a myeloproliferative disorder
o Chronic myelocytic leukemia (CML)
o Polycythemia Vera
o Myelofibrosis
o Multiple myeloma
agranulocytes
- Monocytes
- Lymphocytes
Granulocytes
- Neutrophils
- Basophils
- Eosinophils
Monocytes
- Phagocytes
o Differentiate into macrophages when they migrate into tissue - Fight bacterial infection (similar to neutrophils)
o Remove injured and dead cells, microorganisms and particles – clear debris - Stay in circulation longer than neutrophils
- Monocytosis: indicative of:
o chronic infection (TB, syphilis, malaria),
o chronic inflammatory disorders (RA, Lupus),
o malignancy (if in conjunction with other leukocyte abnormalities)
Lymphocytes
- Primary function is to fight acute viral and chronic bacterial infection
- 2 main types
o T cells - Helper T Cells – stimulate the production of other immune cells
- Killer T Cells - destroy infected cells
o B cells: produce antibodies to attack invading bacteria, viruses and toxins
Lymphocytosis (increased lymphocytes): causes
o Acute infection
* EBV, hepatitis, CMV, HIV, Pertussis, Measles, Mumps, Rubella
o Stress
o Smoking
o Asplenia
o Thymoma
o Autoimmune disorders
* Thyroiditis, RA
o Malignancy (CLL, Non-Hodgkin’s Lymphoma)
Lymphocytopenia (decreased lymphocytes)
- Not typically significant
- Can be seen in:
o Steroid use
o Late stage HIV
o Radiation
o Lupus
Pediatric Variations of WBC
- It is different with neonatal (-4 weeks), infants (4 week+), children (1-8-12 yrs /puberty)
- The WBC is increased and then decreases after the first few weeks and gradually declines to adult levels
WBC Variations in Pregnancy
- The WBC count can increase in the 3rd trimester with a slightly increased percentage of neutrophils
- Will see leukocytosis (increased leukocytes)
- Neutrophil count: increases throughout the pregnancy
- Lymphocyte count: stable
- Monocyte count: stable
- Eosinophil: may slightly increase
- Basophils: may slightly decrease
Platelets (not part of the WBC)
- Function: regulate hemostasis and thrombosis formation = stop bleeding
- Activated by vascular injury, adhere to the extracellular matrix of the vasculature forming a platelet plug
- Platelets are circulating, live for 7-9 days
Thrombocytosis (increased platelets)
- Reactive/secondary causes
o Infection
o Surgery
o Acute blood loss
o Splenectomy
o Iron deficiency anemia
o Living at high altitude
o Strenuous exercise
o Medication - Estrogen, OCPs
- Bone marrow problem (ie essential thrombocythemia)
- Pregnancy
- Thrombocytosis is interchangeable with thrombocythemia.
- Diseases a/w spontaneous thrombocytosis are:
o Iron deficiency anemia
o Malignancy (leukemia, lymphoma, solid tumors)
o Polycythemia vera
o Post splenectomy syndrome
o Acute or chronic infections and inflammatory processes - The main risk in this is a clot, leading to tissue or organ infarction
Thrombocytopenia (decreased platelets)
- Decreased platelet production
- Increased platelet destruction
- Increased platelet sequestration in the spleen
- Hemorrhage
- Medications
o Chemotherapy, H2RAs, isoniazid, indomethacin, sulfas, thiazide diuretics - Bleeding risk
o Assess for any evidence of bleeding
o Correlates with platelet count - Mild 100-150000/microL
- Moderate 50-99000/microL
- Severe < 50000/microL
o Surgical bleeding a concern if <50,000
o Spontaneous bleeding a concern if < 20,000 – urgent referral - Confirm with a Peripheral Blood Smear due to risk of artifact
- Rule out pseudo thrombocytopenia
- Once confirmed it is true thrombocytopenia, confirm etiology
- Bleeding risk
Correlates with platelet count
Mild 100-150000/microL
Moderate 50-99000/microL
Severe < 50000/microL
- Peripheral smear
o Evaluates RBC, WBC, and platelets
o Shape, size, general appearance
o Blood mixed with dye and placed under a microscope
- Flow cytometry
o Measures physical and chemical characteristics of cells
o Looking for abnormal markers on the cell that could indicate, for example, cancerous cells
