Pathology Flashcards Preview

Hematology > Pathology > Flashcards

Flashcards in Pathology Deck (30):
1


Blood sample collection


EDTA anticoagulated tubes (purple top)

Testing within 8 hr for room temp, 24 hr for refrigerated

Artifacts of delay - increased MCV, decreased MCHC, decreased ESR

2


CBC


RBC data - count, HgB, HCT, RBC indices, distribution width

WBC data - count with or without differential

Platelet count, volume

3


RBC total


Adult male - 4.5-6x10^12/L

Adult female - 4-5.5x10^12/L

4


Hemoglobin


Adult male - 14-18 g/dL

Adulte female - 12-16 g/dL

Anemia or polycythemia

5


HCT


Calculated from RBC and MCV

Male - 40-54%

Female - 35-47%

6


MCV


Mean of RBC distribution on histogram

Normally 82-100 um^3

Micro or macrocytosis

7


MCH


Mean corpuscular hemoglobin

 

Normal - 27-34pg

=Hb/RBC

Limited use

8


MCHC


Mean corpuscular hemoglobin concentration

Normal 32-36%

Hb/HCT

Limited use

9


RDW


Red cell distribution width

Degree of variation of RBC size

Normal - 11-15%

Increase - associated with anemia from iron, B12, folate deficiencies

Normal-low - thalassemias or chronic disease anemias

Not specific - interpreted in context of other data

10


Reticulocytes


Automated or manual count

Normal - 0.5-1.5% (20-76B/L)

Low - iron deficiency, folate/B12 deficiency, bone marrow failure

High - acute blood loss, hemolysis

11


Erythrocyte sedimentation rate (ESR)


Normal 0-15 mm/hr

Negative charges on RBCs prevent stacking, but inflammatory proteins allow stacking (sedimentation)

Increased ESR - inflammatory processes - especially temporal arteritis, polymyalgia rheumatica

Not for screening - high false positives/negatives

12

Anemias based on MCV, RDW

A image thumb
13


Iron deficiency anemia


Microcytic hypochromic anemia - low Hb and MCV with increased RDW

Serum iron profile - low iron, ferritin, TIBC

Seen with low to normal reticulocytes, no polychromasia

Smear - small RBCs with increased central pallor

14


Abnormal RBC morphology

Anisocytosis - variation of size

Poikilocytosis - variation in shape

Polychromasia - increased reticulocytes

Spherocytes - small, round RBCs without central pallor - in acquired immune hemolytic anemia, post-transfusion, oxidizing (drug) hemolysis, enlarged spleen hemolysis, hereditary spherocytosis

Eliptocytes/oalocytes - elongated RBC with blunt end - egg to pencil shape

Target cell - dense central area surounded by clear halo, peripheral rim of hemoglobin - in thalassemias, sickle cell (especially HbC), liver disease, post-splenectomy, iron deficiency

Echinocytes (Burr cells) - short, evenly spaced spicules with preserved central pallor - in uremia, bleeding ulcers, gastric cancer, or artifactual

Schistocyte - distorted, fragmented cells with 2-3 points - microangiopathic hemolytic anemia, severe burns, prosthetic valves

Teardrops - from myelophthisis - bone marrow fibrosis from various etiologies (primary, metastatic carcinoma, etc)

Rouleaux - cell aggregates resembling stacked coins - d/t increased serum paraprotein - artifactual or gammopathies

Agglutination - clumping - at cold temperature, not normal body temperature - d/t IgM antibodies against RBC surface - causes hemolysis

15


Sickle cell RBCs


Pointed at both ends

Due to HbS aggregation

Only in sickle cell disease (both alleles), not sickle cell trait (one allele)

Point mutations in beta-globin chain - polymerizes at low oxygen, causing abnormal shape

16


RBC inclusions

 

  • Howell-Jolly bodies - small dense inclusions, usually single - nuclear remnants - seen post-splenectomy, hemolytic anemia, megaloblastic anemias
  • Basophilic stippling - punctate inclusions of precipitated rRNA - fine in anemias, coarse in thalassemia, lead intoxication

17


Microangiopathic hemolytic anemia


Includes thrombotic thrombocytopenic purpura (TTP), DIC, hemolytic uremic syndrom, uremia w/ HTN, sickle cell anemia w/ pulmonary emboli

RBCs fragmented by intravascular fibrin deposit in TTP, DIC

RBC morphologies seen - burr, acanthocyte, spur, fragmented, etc.

18


Neutrophils


50-65% of leukocytes

3-4 lobed nucleus

Circulate only 12 hours

Released into circulation in band stage - nucleus band-shaped, not fully segmented

Recruited into tissues by inflammatory cytokines

19


Neutrophilia


Absolute neutrophils > 7,000/ul

Etiologies

  • Infection
  • Acute stress
  • Acute tissue necrosis (MI)
  • Medications (steroids, lithium, GFs)
  • Pregnancy (3rd trimester)
  • Malignancy

Pathophysiology - initial increased mobilization from marrow pool and circulating blood, later increased production secondary to colony stimulating factors

Reactive morphologic findings

  • Left shift (increased bands)
  • Toxic granulation (increased cytoplasmic granules)
  • Dohle bodies (blue inclusions of aggregated rough ER)
  • Vacuolization of cytoplasm

Differential diagnosis - must determine if neutrophilia is due to myelogenous leukemia or reactive (leukemoid reaction).  Reactive state:

  • Stages of cells - more mature in leukemoid
  • Alkaline phosphatase activity retained in leukemoid
  • Morphologic findings present
  • Basophilic
  • Philadelphia chromosome absent

20


Neutropenia


Absolute PMN < 1800/ul

Increased susceptibility to infection

Agranulocytosis - virtual absence d/t depletion of marrow and circulating pools

May require antibiotic prophylaxis

Pathophysiology

  1. Decreased marrow production - aplastic anemia, viral suppression, drug-related, Kostmann syndrome (congenital lack)
  2. Ineffective marrow production - megaloblastic anemia, myelodysplasia
  3. Increased peripheral destruction - antibody-mediated, infection, hypersplenism

21


Neutrophil morphologic abnormalities

 

  • Nuclear abnormalities - no functional implications
  1. Pelger Huet anomaly - hyposegmentation - AD or acquired (myelodysplasia)
  2. Hypersegmentation (5+) - megaloblastic anemia, hydroxyurea

22


Lymphocytes


25-40% of leukocytes (higher in children)

Round to oval, non-segmented nucleus

Small cytoplasm

80% T cells

Large granulated lymphocytes - cytotoxic T cells, NK cells - more cytoplasm than others

Involved in humoral, cell-mediated immunity

23


Lymphocytosis


Absolute lymphocyte count > 5000ul (7000 in children, 9000 in infants)

Etiology: infection (viral), lymphoproliferative disorders, immunologic reactions (drugs, serum sickness)

Types:

  • Small, mature - e.g. pertussis
  • Reactive atypical lymphocytes - large, smudgy chromatin, larger cytoplasm - usually CD8 - e.g. in EBV infection
  • Large granular lymphocytes - HIV, rheumatoid arthritis, leukemias

24


Monocytes


5-12% of leukocytes

Irregular, non-segmented nucleus

Abundant blue cytoplasm with some granules, vacuoles

Migrate into tissues to become macrophages

Function in inflammation

25


Monocytosis


Absolute monocytes > 800/ul

Etiology:

  • Chronic inflammation
  • Chronic infection (TB)
  • Neutropenia - relative increase
  • Clonal disorders - monocytic leukemia

 

26


Eosinophils


3% of leukocytes

Segmented 2-lobe nucleus

Orange-red cytoplasmic granules

Migrate into tissues or mucosa

In allergic reactions, parasitic infections

27


Eosinophilia


Absolute eosinophils >350/ul

Etiology:

  • Infectious disease
  • Allergic reaction
  • Asthma
  • Collagen vascular disease
  • Neoplastic process

 

28


Hypereosinophilic syndrome


Unexplained eosinophilia >6 months

Count often >1500/ul

Eosinophils have abnormal morphology

Tissue infiltration in heart, lungs, CNS causing damage

Treat with steroids and/or chemotherapy

29


Basophils


1% of leukocytes

Segmented nucleus

Numerous purple cytoplasmic granules - mostly histamine

Distinct from mast cells (tissue cells)

Immediate hypersensitivity reactions

30

Functional leukocyte defect


Chronic granulomatous disease

X-linked deficiency of NADPH oxidase

Impaired respiratory burst and peroxide production

Recurrent bacterial infections - especially catalase-positive organisms