THE BLOODY TRUTH ABOUT CATS AND DOGS, HEMATOLOGY BASICS: DIFFERENTIALS

HEMATOLOGY BASICS: DIFFERENTIALS

By Sarah Ouellette CVT.

1. T H E BL OO D Y T RU T H AB OU T C A T S A N D DOG S H E M A T O L OG Y BAS I C S : D I FFE R E N T I A L S Sarah Ouellette CVT.

2. THE WHITE BLOOD CELL: LEUKOCYTES

3. W hi t e Bloo d C ell s Five major White Blood Cells Further defined into two groups: Granulocytes Neutrophils Eosinophils Basophils Monocellular cells (agranulocytes) Lymphocytes Monocytes

4. W hi t e Bloo d C ell s 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. 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. Neutrophils Morphology: Canine : white cytoplasm with sm. pink granules, multi-lobed nuclei with condensed chromatin that stains deep purple

7. Neutrophils Morphology: Feline: white/pink cytoplasm witch lacks visible granules, multi-lobed nuclei with condensed chromatin that stains deep purple

8. Granulocytes Eosinophils Second most common granulocyte Slightly larger than neutrophils Function: Hypersensitivity reactions Parasitic infections Allergic reactions

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. 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. 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. Granulocytes Basophils Occasionally observed/difficult to find Slt larger than neutrophils Commonly mistaken for monocytes Function: Hypersensitivity reactions Parasitic infections Allergic reactions

13. Ba s ophil s 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. Ba s ophil s Can i ne Feli n e

15. M ono c ellula r c ell s Lymphocytes Second most common WBC seen Slightly larger than red blood cells Commonly confused with nRBC Function: Antibody immunity Cell mediated immunity

16. L y m pho cy t e s 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. n R B C v . s l y m pho cy t e s nRBC • lymphocyte

18. L y m pho cy t e s Metarubricyte Ba s oph i l ic rubricyte Small l y m pho c y t e

19. M ono c ellula r c ell s Monocytes Largest WBC Increased # indicative of chronic inflammation Function: Phagocytosis Release inflammatory mediators

20. M ono cy t e s 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. M ono cy t e s Can i ne

22. M ono cy t e s Fe l ine

23. I mm a t ur e W B C 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. I mm a t ur e W B C (neu t rophil s ) Shape of the nucleus differentiates these cells Myelocyte – nucleus appears round Metamylocyte – kidney bean shape Band cell- horseshoe shape Mature cell – segmented

25. I mm a t ur e W B C Band cells Widths of the nuclear margins are smooth and parallel

26. T o x i c c hange s 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. T o x i c C hange s 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. T o x i c c hange s Cytoplasmic basophillia - cytoplasm develops a streaky irregular darker blue appearance Presence of dohle bodies Cytoplasmic vacuolation - vacuoles are present within the cytoplasm of the cell giving it a frothy appearance Vacuolation can also be a storage related artifact Nuclear immaturity - nuclear chromatin is lighter, finer and less clumped than that of normal cells often subtle and difficult to visualize Toxic granules – distinct fine granules in the cytoplasm change is not common and can be difficult to visualize

29. T o x i c C hange s ( N eu t rophil ) 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. T o x i c C hange s 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. T o x i c C hange s 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. T o x i c C hange s 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. Abnor m a l W B C 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. Abnor m a l W B C 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. Abnor m a l W B C 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. Pelge r -hue t ano m al y

37. W B C I n c lu s ion s Usually include or represent phagocytosed material such as other cells, cell debris, retained cellular material and infectious organisms

38. W B C I n c lu s ion s 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. W B C I n c lu s ion s Barr body Found in neutrophils Appendage attached to nucleus Small tennis racket shape No pathological significance Indicates that the dog is female

40. W B C I n c lu s ion s Dohle Body Small irregular pale blue aggregate Present in cytoplasm of neutrophils Represents aggregates of the rough endoplasmic reticulum Seen in toxic changes

41. W B C I n c lu s io n 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. W B C Para s i t e s 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. W B C Para s i t e s 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. H epa t o z oo n c ani s

45. W B C Para s i t e s 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. Ehrli c hi a s p p . 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. Ehrli c hi a e w ingl i

48. W B C Para s i t e s 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. Anapla s m a phago cyt ophilu m Morphology: Small deep blue/purple structures Grouped individually or in grape-like clusters Observed in cytoplasm of circulating neutrophils and rarely in eosinophils

50. PLATELETS: THROMBOCYTES

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. 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. 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. 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. T hro m bo cy t e Abnor m ali t ie s 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. T hro m bo cy t e Abnor m ali t ie s Activated platelets: Spider/Thread-like projections Fibrin strands Smaller body Form platelet clumps Non-pathological finding

57. T hro m bo cy t e Abnor m ali t ie s Clumping Causes: Sample collection (slow venipuncture) Age of the sample (samples over 24 hours are prone to clumping) 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. Thrombocytes Platelet clumping on feathered edge (10x magnification)

59. T hro m bo cy t e Abnor m ali t ie s 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. M ega t hro m bo cy t e s

61. Pla t ele t di s order s Quantitative abnormality Thrombocytopenia: Decreased number of platelets Normal function Caused by: Increased utilization of platelets Increased destruction of platelets Decreased production

62. Pla t ele t di s order s 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. Pla t ele t di s order s 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. Questions?