Docstoc

The Peripheral Smear for the Internist

Document Sample
The Peripheral Smear for the Internist Powered By Docstoc
					Practical Utilization of the Complete Blood Count
Joseph M. Flynn, D.O.,MPH, FACP Division Hematology-Oncology THE Ohio State University Columbus, OH April 18, 2008

Introduction
Overview of Components of CBC  White Blood Cells  Hemoglobin / Hematocrit  Platelets  Cell Morphology  Secondary Testing


Complete Blood Count - CBC



    

WBC Hemoglobin / Hematocrit MCV RDW MCHC / MCH Platelets Differential Count
 Manual

 Machine

When Assessing Cytopenias Always Think Three Things

making enough  Losing cells  Cell destruction

 Not

WHITE BLOOD CELLS

Blood Cell Formation
Stem Cell

Proerythoblast
Myeloblast

Promyelocyte

Erythrocyte Eosinophil

Neutrophil

Lymph Plasma Cells Basophil Monocyte

White Blood Cells


Neutrophils
Absolute

Neutrophil Count

 WBC x Neu% (segmented neutrophils and bands)

Lymphocytes  Monocytes  Eosinophils  Basophils


What to Do if WBC Abnormal
Take a Good History  Physical Examination


Look

at Old CBC’s!!!!

Neutrophils
60 - 70 % of Circulating Leukocytes  Half Life

Six

to Seven Hours in blood One to Two Days in Connective Tissue


Primary Defense against Bacteria

Neutrophils


Neutropenia
Absolute

Neutrophil Count < 1500

 (Often < 1000 in African Americans)  

Neutrophilia
Absolute Elevation

Neutrophil Count > 8000 in WBC

Leukemoid Reaction
 Typically < 50,000

Neutropenia


Decreased Production
 Infections  Severe Bacterial  Viral  Rickettsial
 Drugs  Antibiotics  NSAIDS  Others  Hematological



Decreased Survival
 Infections
 Drugs  Immune  SLE  Cyclic

mediated

Disease

 Dietary
 Shock  Severe

Renal Disease

Evaluation of Neutropenia

Consider Heme Consult

Adapted from Goldman: Cecil Medicine, 23rd ed.

Benign (Ethnic) Neutropenia



Characterized by neutrophil counts 800 to 1400/mm3 Generally a benign course
 Sometimes

associated with periodontal disease  No increase in infections
 

Bone marrow is typically normocellular Seen in African American, some Jewish populations

Neutrophilia
 

Acute Infections
 Leukocyte:

15-25 X 109/L.

Inflammation
 Postoperatively,

neutrophilia occurs for 12-36 hours as a result of tissue injury



Metabolic
 Uremia,  DKA  Eclampsia



Chemicals
 Steroids  Epinephrine

Neutrophilia


Acute Hemorrhage
 Related

to the release of adrenal corticosteroids and/or epinephrine

    

Acute Hemolysis Myeloproliferative disorders Tissue Injury Tobacco Use Physiological Stress
 Exercise
 Emotional

Stress  Menstruation

Steroid Effect
Increases total and relative PMN’s  Peak is 4-6 hours  Normalizes in 24 hours after steroids stopped  Usually see a concurrent decrease in Lymphocytes and Monocytes


Lymphocytosis


Infections
 Viral  Hepatitis  CMV  Tuberculosis

  




Addisons Disease Leukemia Ulcerative Colitis / Crohn’s Disease Vasculitis Drug Hypersensitivity

Lymphopenia



Increased Destruction
 Corticosteroids

Congestive Heart Failure
 Loss

through GI tract



Decreased Production
 Malignancies  Immunoglobulin  HIV

Disorders

Infection  Lupus

Eosinophilia



 


   

> 250/ CU MM Highest Levels in am Allergic Diseases Parasitic Infections: Trichinosis, Schistosomiasis Leukemias Familial Addison’s Disease, Hypopituitarism Drugs: Aspirin Collagen Vascular Diseases: Churg-Strauss, Scleroderma/dermatomyositis, RA, SLE, Periarteritis Nodosa

Monocytosis




> 10% of differential Elevated in:
 Leukemia  Hodgkins

/ Non Hodgkins lymphoma  Post Splenectomy  Protozoan Infections  Rickettsial Infections: Rocky Mountain Fever, Typhus  Sarcoidosis  Collagen Vascular Diseases  Enteritis

Hemoglobin


Boys and girls are same until @ age 11
Boys

values slowly become higher Adult levels reached
 Age 15 Women  Age 18 Men
African

Americans 0.5 - 1.0gm (5-10 g/dL) lower than northern Europeans Positional differences
 Upright vs post bedtime

Changes in Hgb
Not Due to Blood Loss or Abherrent Condition


Increased:
Increased Smoking Dehydration Triglycerides



Decreased
Position Pregnancy Diurnal Race Females IV

WBC

 WBC >50,000

 >2000

fluids

MCV Falsely Abnormal
Cold Agglutinins  Hyperglycemia  Reticulocytosis  Leukocytosis  Acute Hemolysis


RDW vs MCV


Normal RDW ; Low MCV
 Thalassemia  Chronic



Normal RDW ; Normal MCV
 Chronic

disease

Disease



Normal RDW ; High MCV
 Aplastic

Anemia  Myelodysplasia  Alcohol
Adapted: Ravel; 1995; 14

(90%)  Hereditary Spherocytosis  Acute Bleed  Cirrhosis  Uremia

RDW vs MCV


HIGH RDW ; Low MCV
 Iron



HIGH RDW ; Normal MCV
 Early

Deficiency  S-Thalassemia  RBC fragmentation


HIGH RDW ; HIGH MCV
 B12/Folate
 Autoimmune

Factor Deficiency  SS disease  SC dz  Sideroblastic anemia  Myelofibrosis

hemolysis  Cold Agglutinins

Pathophysiologic Classification Anemia
Due to Decreased RBC Production  Due to RBC Destruction

0.8

% rbc’s destroyed daily Best suited for relating disease processes to their mechanisms Limited in the complexity of mechanisms and lack of solidly established mechanisms

Microcytosis Differential Diagnosis
Iron Deficiency  Thalassemia

Beta-Thalassemia:

Elevated Hgb A2 or F alpha Thalassemia diagnosis of exclusion



Anemia of Chronic Disease
Though

75% patients are normocytic

Sideroblastic anemia - rare  Lead poisoning - rare

Iron Deficiency
Most common cause of microcytosis  Clinical Clues  Iron Studies

Iron

Iron Binding Capacity Ferritin  Iron Saturation (Serum Iron / TIBC ) < 10 % saturation

Total

Iron
Serum Iron Iron Deficiency Sideroblastic Thalassemia Anemia of Chronic Disease Low Elevated TIBC Elevated Nml Nml Low Ferritin Low Elevated Elevated Elevated

Elevated
Low

When Do I Get a Hemoglobin Electropheresis
Iron studies not indicative of another process  Family history of hemoglobinopathy  African American  Asian decent  Mediterranean decent  Microcytosis in face of mild-No anemia


Macrocytosis MCV > 100
   


 


 

Folate/B12 Chronic Liver dx Alcoholism Chemotherapy Reticulocytosis Myelodysplastic Unknown Distance runners Hypothyroidism ** Hyperlipidemia **

20 - 30% 15 - 20% ** 10 - 12% - Can occur with 1bottle of wine per day 10 - 15% 7% Common 25%
**Lipid membrane defects

Evaluation of Macrocytosis
History  Physical  False Macrocytosis

Cold

agglutinins: RBC clumping Hyperglycemia: Hyperosmolarity Leukocytosis: WBC counted as RBC

Evaluation of Macrocytosis
  

B12 / Folate
Look

for hypersegmented neutrophils

Thyroid Studies
If

clinically indicated

Liver Associated Enzymes  Reticulocyte Count

Megaloblastic Anemia


Hypersegmented Neutrophils
Any

neutrophil with > six segments or More than five percent with five segments or Majority of cells with four segments


Presence of Macroovalocytes
Egg

- shaped cells

The combination is a result of absence of terminal divisions of marrow precursors

Megaloblastic Anemia Diagnosis


Serum folate levels may be misleading
 Alcohol

lowers the folate levels  Correcting serum folate can be seen after a meal
 

Determine the cause of the deficiency
 Ie.

Pernicious anemia, Malabsorption, Diet

Red cell changes are not seen in all vitamin deficient patients
 MCV

usually > 110 though > 130 more specific  Look at RDW  Cell Morphology

Diagnosing Vitamin Deficiencies


Serum cobalamin
<

200 pg/ml: consistent with Cobalamin deficiency >300 pg/ml: Normal


Serum folate concentrations
If

Folate is >4ng/ml then not folate deficient If Folate is < 2ng/ml then folate deficient If Borderline, Check Red blood cell levels

Diagnosing Vitamin Deficiencies


Methylmalonic acid and Homocysteine
Good

if Cobalamin and Folate are equivocal Both elevated = Cobalamin Deficiency
 95% Sensitivity  99% Specificity
If

Homocysteine only elevated = Folate Deficiency
 85% Sensitivity



Anti-Intrinsic factor Antibodies Confirms Pernicious Anemia

Consider Lab Error

MCV >100

Rule out Drugs

Retic ct High Blood Loss
Eval for Hemolysis
LDH Bilirubin Haptoglobin

B12 & Folate

LOW

LFT’s Thyroid

Normal
MMA & HC Consider Bmbx

Most commonly Myelodysplasia

Adapted from Colon-Otero, Med Clin of NA. 76(3)581-596. 1992

Normocytic Anemia Differential Diagnosis



  


 

Acute Hemorrhage Hemolysis Aplastic Anemia Renal Failure Myelophthisis Sickle cell anemia Chronic Disease Combined Microcytosis / Macrocytosis

Normocytic Anemia Evaluation
Clinical History  Review CBC for multiple Cell line deficiencies  RDW / Smear

Malnutrition

Direct Antibody Test  Chemistries  Consider Bone Marrow Biopsy


Red Blood Cells
 Spherocytes

Cells  Schistocytes  Tear Drop Cells  Basophilic Stippling  Howell-Jolly Bodies

 Sickle

Schistocytes
Differential Diagnosis
Mechanical Valves  Stenotic Valves  Malignant Hypertension  Disseminated Intravascular Coagulation DIC  Hemolytic Uremic Syndrome – HUS



Thrombotic Thrombocytopenic Purpura

Platelets
Size should be <1/3 that of RBC  Thrombocytopenia: < 150,000

<

100,000 is important number Should be suspected when platelets are found in <1 in 10 fields on high power

Thrombocytosis: >450,000/cu mm  Pseudothrombocytopenia


Thrombocytopenia
Decreased Production  Acute Infection  Increased Destruction  Consumption  Primary or Hereditary


Thrombocytopenia
> 50,000: Typically no bleeding  20 – 50,000: Post operative bleeding and minor mucosal bleeding  5 – 20,000: Can have significant bleeding  <5,000: Severe bleeding possible

Unless

ITP

Pseudothrombocytopenia



EDTA related platelet clumping
Clinically

insignificant

Cold Agglutinins  Giant Platelets  Erythrocytosis

Idiopathic Thrombocytopenic Purpura
IDIOPATHIC  Bleeding unlikely unless < 10,000  Diagnosis of exclusion  Bone marrow biopsy necessary only in those > 60 years old


Thrombocytosis


Infection
 Acute Phase Reactant  1/3 of patients

    



Inflammatory State Malignancy Recent Surgery Iron Deficiency Anemia Trauma Myeloproliferative Disorder
 >600,000

on two occasions


				
DOCUMENT INFO
Shared By:
Categories:
Tags:
Stats:
views:55
posted:11/15/2009
language:English
pages:48