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Hematology basics pt 2

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Hematology basics pt 2

  1. 1. THE BLOODY TRUTH ABOUT CATS AND DOGS HEMATOLOGY BASICS: DIFFERENTIALS Sarah Ouellette CVT.
  2. 2. THE WHITE BLOOD CELL: LEUKOCYTES
  3. 3. White Blood Cells • Five major White Blood Cells • Further defined into two groups: 1. Granulocytes • Neutrophils • Eosinophils • Basophils 2. Monocellular cells (agranulocytes) • Lymphocytes • Monocytes
  4. 4. White Blood Cells • Granulocytes: • Classified due to the granules present in their cytoplasm • Monocellular cells (agranulocytes): • Classified due to their round globular shaped nucleus ** somewhat misleading due to the fact that most monocytes do not have a round nucleus**
  5. 5. Granulocytes • Neutrophils (segmented neutrophils, segs) • Most predominant WBC in healthy animals • First line of defense against infections • 1 ½ times the size of RBC’s • Function: • Seek out, ingesting, killing, and invading microorganisms
  6. 6. Neutrophils Morphology: • Canine: white cytoplasm with sm. pink granules, multi-lobed nuclei with condensed chromatin that stains deep purple
  7. 7. Neutrophils Morphology: • Feline: white/pink cytoplasm witch lacks visible granules, multi-lobed nuclei with condensed chromatin that stains deep purple
  8. 8. Granulocytes • Eosinophils • Second most common granulocyte • Slightly larger than neutrophils • Function: • Hypersensitivity reactions • Parasitic infections • Allergic reactions
  9. 9. Eosinophils Morphology: • Canine: variable in size, round-oval in shape. The cytoplasm is faint blue/pink that contains round pink-orange granules, lobed nuclei with condensed chromatin (less lobed than neutrophils)
  10. 10. Eosinophils Morphology: • Feline: uniform in size and shape. The cytoplasm is faint blue/pink that contains rod shaped pink- lavender granules, lobed nuclei with condensed chromatin (less lobed than neutrophils)
  11. 11. Eosinophils • A specific morphologic variant of the eosinophil is seen in greyhounds and other sighthounds • Lack visible granules and appear as cells with slightly segmented nuclei, grey/lavender cytoplasm, and vacuoles.
  12. 12. Granulocytes • Basophils • Occasionally observed/difficult to find • Slt larger than neutrophils • Commonly mistaken for monocytes • Function: • Hypersensitivity reactions • Parasitic infections • Allergic reactions
  13. 13. Basophils Morphology: • Nucleus is segmented with dense chromatin • Can also commonly have a kidney bean shaped nucleus • Cytoplasm is pale blue/grey/lavender • Contains a few distinct dark blue/purple granules • Distinct “cobblestone” appearance • Cytoplasm MAY contain small vacuoles • Most commonly confused with monocytes
  14. 14. Basophils • Canine • Feline
  15. 15. Monocellular cells • Lymphocytes • Second most common WBC seen • Slightly larger than red blood cells • Commonly confused with nRBC • Function: • Antibody immunity • Cell mediated immunity
  16. 16. Lymphocytes Morphology: • Small amount of light blue cytoplasm • Coarsely clumped chromatin • takes up the majority of the cell • Nucleus is round-oval in shape • may be slightly indented
  17. 17. nRBC v.s lymphocytes • nRBC • lymphocyte
  18. 18. Lymphocytes Metarubricyte Basophilic rubricyte Small lymphocyte
  19. 19. Monocellular cells • Monocytes • Largest WBC • Increased # indicative of chronic inflammation • Function: • Phagocytosis • Release inflammatory mediators
  20. 20. Monocytes Morphology: • Variable in shape from round to angular • Grey/blue cytoplasm • Nucleus is irregular and variable in shape • and has a lacey less dense chromatin pattern • May have a few small vacuoles (not distinguishing factor)*
  21. 21. Monocytes • Canine
  22. 22. Monocytes • Feline
  23. 23. Immature WBC Left shift • Increased numbers of immature neutrophils • Most common cause is inflammation • Can also be seen in some marrow disorders (leukemia) or severe bone marrow injury • Cells are classified based on their stage of maturation
  24. 24. Immature WBC (neutrophils) • Shape of the nucleus differentiates these cells • Myelocyte – nucleus appears round • Metamylocyte – kidney bean shape • Band cell- horseshoe shape • Mature cell – segmented
  25. 25. Immature WBC • Band cells • Widths of the nuclear margins are smooth and parallel
  26. 26. Toxic changes • Hypersegmentation • Neutrophil with 5 or more lobes • Causes: • Common ageing artifact • Exposure to excessive amounts of EDTA • Also seen in: • Glucocorticoid therapy • Hyperadrenocorticism • Chronic infections
  27. 27. Toxic Changes Toxic Neutrophils • Occurs when the maturation in the bone marrow is accelerated • Often accompanied by a left shift • Causes: • Inflammation • Graded as mild, moderate and severe • Severity of abnormalities and number of cells affected • We evaluate five main features to determine toxicity…
  28. 28. Toxic changes 1. Cytoplasmic basophillia - cytoplasm develops a streaky irregular darker blue appearance 2. Presence of dohle bodies 3. Cytoplasmic vacuolation - vacuoles are present within the cytoplasm of the cell giving it a frothy appearance • Vacuolation can also be a storage related artifact 4. Nuclear immaturity - nuclear chromatin is lighter, finer and less clumped than that of normal cells • often subtle and difficult to visualize 5. Toxic granules – distinct fine granules in the cytoplasm • change is not common and can be difficult to visualize
  29. 29. Toxic Changes (Neutrophil) A: Normally matured segmented C: late band neutrophil Both: white cytoplasm with pink granules long and fairly narrow nuclei tightly condensed chromatin B: Segmented D: Band neutrophil Both: with toxic changes Nucleus is larger less condensed chromatin bluer cytoplasm due to retention of ribosomal RNA
  30. 30. Toxic Changes Reactive Lymphocytes • Large lymphocytes • Seen in: • Antigenic stimulation • Relatively non-specific finding • Any disease process can cause an antigenic stimulation leading to the presence of these cells in circulation
  31. 31. Toxic Changes Reactive Lymphocytes • Extremely variable in size and morphologic features • Chromatin is coarsely clumped • Nucleus is extremely variable in shape • Can have an increased amount of cytoplasm • Cytoplasm stains deep blue/purple
  32. 32. Toxic Changes Granular lymphocytes • Usually found in low numbers in healthy animals • Caused by chronic antigenic stimulation • Distinguished by the presence of distinct pink granules collected into one area of the cytoplasm
  33. 33. Abnormal WBC • Mast cells • Rarely seen in peripheral blood smears • Large irregular deeply staining • Round/oval nucleus difficult to visualize • Large amounts of deep blue cytoplasm • Numerous small purple cytoplasmic granules • Seen in: • Inflammatory diseases • Certain neoplastic diseases
  34. 34. Abnormal WBC • Smudge Cells or Blast cells • Dying WBC’s • Normal to see an occasional cell • Increased numbers are indicative of leukemia • May be an artifact of slide preparation • By applying too much pressure to the slide
  35. 35. Abnormal WBC • Pelger-huet anomaly • Congenital disorder in dogs • All the granulocyte nuclei fail to undergo segmentation • Can also occur in certain drug interactions Morphology: • Nucleus is uniform • Lacks the toxic changes • distinguishes this from an inflammatory process • Accompanied by a normal leukogram • Neutrophils have a normal function
  36. 36. Pelger-huet anomaly
  37. 37. WBC Inclusions • Usually include or represent phagocytosed material such as other cells, cell debris, retained cellular material and infectious organisms
  38. 38. WBC Inclusions • Chediak Higashi Syndrome • Syndrome of cats (Persians) • Neutrophillic inclusion • Variable size • Round, pale blue/pink • Attaches to granules in cytoplasm • Usually see 1:3 ratio • Tend to have lower platelet numbers • Otherwise healthy
  39. 39. WBC Inclusions • Barr body • Found in neutrophils • Appendage attached to nucleus • Small tennis racket shape • No pathological significance • Indicates that the dog is female
  40. 40. WBC Inclusions • Dohle Body • Small irregular pale blue aggregate • Present in cytoplasm of neutrophils • Represents aggregates of the rough endoplasmic reticulum • Seen in toxic changes
  41. 41. WBC Inclusion • Distemper virus • Aggregates of viral particles • Round and variable in size • Pink/lavender in color • Found in RBC,WBC • Rarely seen even with + infection
  42. 42. WBC Parasites • There are several organisms that can be detected from examination of a peripheral blood smear, however they can be intermittently seen and therefor further serological testing should be done • Transmission most commonly occur through the bites of ticks
  43. 43. WBC Parasites Hepatozoon canis • Protozoal parasite transmitted via ticks • Not commonly seen even with active infection • Accompanied by a severe leukocytosis • Found in a small number if cells Morphology: • Large aqua-staining rod • Esinophilic patches • May distort the cell border • also be seen as a clear capsule
  44. 44. Hepatozoon canis
  45. 45. WBC Parasites Ehrlichia ewingli and Ehrlichia canis • Bacterial parasite transmitted via ticks • More commonly seen in the south • Dogs can be asymptomatic or present with a fever and polyarthritis • Accompanied by moderate leukopenia and severe thrombocytopenia • Rarely seen on direct smear • Is a zoonotic dz
  46. 46. Ehrlichia spp. Mporohology: • E. ewingli morula – found in neutrophils • E. canis – found in lymphocytes and monocytes • Both appear as medium well defined round-oval inclusions within the cytoplasm that stain deep blue/purple
  47. 47. Ehrlichia ewingli
  48. 48. WBC Parasites Anaplasma phagocytophilum • Tick-born bacterial parasite • Accompanied by a mild to moderate nonregenerative anemia and thrombocytopenia • Not commonly seen even with a positive infection • Is a zoonotic disease
  49. 49. Anaplasma phagocytophilum • Morphology: • Small deep blue/purple structures • Grouped individually or in grape-like clusters • Observed in cytoplasm of circulating neutrophils and rarely in eosinophils
  50. 50. PLATELETS: THROMBOCYTES
  51. 51. Thrombocytes • 1’st line of defense for the normal function of clotting • (aka: hemostasis) • Formed and released from the bone marrow • Lifespan in the blood is 5-10 days • Observed/counted in counting area of the blood smear • Scan feathered edge of the smear to observe for clumps
  52. 52. Thrombocytes Morphology • Lack a nucleus • Vary greatly in size, shape, and granularity • Often have fuzzy edges • Can have string-like projections arising from the body of the cell • Stain pale lavender to dark purple
  53. 53. Thrombocytes Normal morphology: Dog • Round, discoid, oval, elongated, or flat • Some appear granular • Containing few purple/blue granules surrounded by a pale blue matrix
  54. 54. Thrombocytes Morphology: Cat • Morphologically similar to the dog • Spherical or elongated • Tendency to clump • More variable in size • May be as large as the red blood cells • considered normal
  55. 55. Thrombocyte Abnormalities • 90% of bleeding disorders in dogs and cats results from abnormalities with either platelet numbers or platelet function • Greyhounds tend to have a lower number of platelets overall
  56. 56. Thrombocyte Abnormalities Activated platelets: • Spider/Thread-like projections • Fibrin strands • Smaller body • Form platelet clumps • Non-pathological finding
  57. 57. Thrombocyte Abnormalities Clumping • Causes: 1. Sample collection (slow venipuncture) 2. Age of the sample (samples over 24 hours are prone to clumping) 3. Common in cats but is normal • The feathered edge should be scanned first to observe for this abnormality, the clumps being heavier tend to be pushed to the edge of the smear
  58. 58. Thrombocytes • Platelet clumping on feathered edge (10x magnification)
  59. 59. Thrombocyte Abnormalities Mega platelets or megathrombocytes • Large platelets • Can be an indication of an early production and release • May be as large as the RBC’s • Can be a normal in cats
  60. 60. Megathrombocytes
  61. 61. Platelet disorders Quantitative abnormality • Thrombocytopenia: • Decreased number of platelets • Normal function • Caused by: • Increased utilization of platelets • Increased destruction of platelets • Decreased production
  62. 62. Platelet disorders Qualitative abnormalities: • Numbers are normal but the function is compromised • Hereditary function defect • Ex: von wilebrans disease and hemophelia • Very rare defect • Usually accompanied by and anemia and/or neutropenia • Other causes: • Cancer, immune or infectious etiologies, NSAID’s
  63. 63. Platelet disorders Thrombocytosis: • Increase in the number of platelets • Very rare, usually secondary to another problem • Causes: • Iron deficiency’s anemia, certain inflammatory conditions, severe trauma (fractures), certain drug therapies, neoplasia, certain gastrointestinal diseases • Transient thrombocytopenia caused by excessive exercise or epinephrine injections
  64. 64. Questions?

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