Lymphoreticular cell biology of exotic species

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Created by
Lucy The 3rd

Cards (47)

  • Rabbit Venipuncture - environment + preparation
    Ensure proper, safe restraint at all times.
    Circulatory volume is approximately 55-70ml/kg.
    Can collect up to 10% of this (i.e. 5.5-7.5ml/kg).
    Rabbit blood tends to clot very quickly.
  • Rabbit Venipuncture - sample types
    EDTA - haematology
    Serum/Heparin - biochemistry (use heparin if restricted on sample volume).
    Fluoride Oxalate - glucose
  • Rabbit Venipuncture - locations
    • Jugular vein
    • Similar technique to cat, Dewlap can get in the way, restraint may inhibit respiration.
    • Cephalic
    • Saphenous
    • Marginal ear vein (not middle vein)
    • Small gauge needles and 1ml syringe.
    • Pinna necrosis if poor/rough technique, but smaller area effected compared to artery.
  • Guinea pig Venipuncture - locations
    Cephalic vein (situated more lateral).
    Cranial vena cava most useful for large blood draws.
  • Rat, mouse, gerbil and hamster Venipuncture
    Blood volume of 60-70ml/kg (on average).
    Safe volumes of blood sample = 1% BW rule.
    Locations:
    • Lateral tail vein (warm tail first).
    • Lateral saphenous vein.
    • Cranial vena cava.
  • Ferret Venipuncture
    Very similar to a small wriggly cats.
    Skin can be very thick especially in mature hobs.
    Blood volume = 50-70ml/kg.
    May require sedation or GA to restrain adequately (latter can lower measured PCV).
    Locations:
    • Jugular vein (more lateral compared to cat).
    • Cranial vena cava.
  • Hedgehog Venipuncture
    Patient lateral recumbency with leg to be sampled on table - area is clipped and prepped.
    All require GA.
    Locations:
    • Cranial vena cava.
    • Jugular vein (hard to visualise due to thick skin).
    • Femoral vein (inside hind leg).
  • Cranial vena cava method in blood sampling
    Useful in many smaller species such as guinea pigs, ferrets, sugar gliders, hedgehogs ect.
    Potential for severe complications if performed incorrectly.
    In some species (e.g. guinea pig, hedgehog) the heart lies very close to sample site.
    Thoracic pathology may change normal anatomy (radiograph dust helps).
    Anaesthesia is essential
  • How to sample blood with the cranial vena cava method.
    Patient in dorsal recumbency, head extended and forelimbs retracted caudally.
    25G, 0.5” needle (or similar).
    Needel placed at the notch where first rib meets the manubrium.
    Advance towards the contra-lateral hindlimb.
    Approximate 30 degree angle until blood flash.
  • Reptile Venipuncture - location + environment
    Most veins are not visible = use landmarks and feel.
    The lymphatic system is closely associated with blood vessels which may lead to contamination of blood samples (affects PCV and some biochemistries).
    Blood pressure low and blood draws slowly.
    As with all animals, ensure you always do a fresh blood smear.
  • Reptile Venipuncture - sample tubes
    EDTA - tends to haemolyse reptile blood cells.
    Lithium Heparin - is anticoagulant of choice, ca clump cells so good for biochem but not haem.
    Make two good quality fresh smears.
    Haemotology is usually performed Malay since automated techniques are made difficult due to Nucleated red blood cells.
    Skin is often heavily contaminated so ensure thorough skin preparation.
  • Circulating blood volume in reptiles

    Approximately 5-8% of bodyweight
    May collect up to 10% (i.e. 5-8ml/kg)
    But many reptiles are presented in poor to very poor health and are often anaemic.
    Therefore often only take half the amount of blood.
    Rarely require more than 2ml.
  • Ventral coccygeal vein - Lizard Venipuncture
    Tail vein.
    Most useful in lizards.
    Entry approximately 1/3rd down the tail to avoid hemipenes and anal glands.
    Ventral or lateral approach may be used.
    Beware tail anatomy of some species (especially Geckos as can drop their tail).
    General anaesthesia helps prevent this problem.
  • Reptile Venipuncture - ventral abdominal vein
    May be visualised in some species.
    Difficult to prevent haematoma if used.
  • Reptile Venipuncture - jugular vein
    Useful in large, longer necked species such as monitor lizards.
    Blind approach along imaginary line from dorsal ear to shoulder.
    Often quite superficial.
  • Snake Venipuncture - ventral coccygeal vein
    Similar approach to lizards.
    Difficult in small snakes.
  • Snake Venipuncture - heart
    Dorsal recumbency.
    Heart located visually, with Doppler or ultrasound.
    Stabilise heart between finger and thumb.
    Needle entry ventral midline at a 30 degree angle in a cranial direction (aim for caudal point of ventricle).
  • Snake Venipuncture - palatine veins
    Prone to haemotoma formation.
    Large, anaesthetised snakes only.
    In books, but rarely used in practive.
  • Chelonia Venipuncture - jugular vein
    Along line from dorsal ear scale to shoulder.
    Tends to be superficial.
    Visible in some species.Lymph contamination least likely
    Coratid artery is deeper and more ventral.
  • Chelonia Venipuncture - sub-carapacial vein
    Entry point cranio-dorsal midline where skin joins carapace.
    Aim for point at junction of 1st and 2nd vertebral scute on midline.
    May need to be needle slightly.
    Head may be retracted or extended.
  • Chelonia Venipuncture - dorsal coccygeal vein
    Often superficial.
    Aim as far cranially as possible.
    Often lymph contaminated.
  • Rabbit Erythrocytes
    Same as other animals.
    Anisocytosis (RBCs are unequal in size) and Polychromasia (high number of immature RBCs) is a common, normal finding.
    May be due to shorter erythrocyte life span (57-67 days).
  • Rabbit white blood cells
    Heterophils have granular cytoplasm and may be mistaken for eosinophils.
    Basophils are present quite commonly.
    Lymphocytes, eosinophils and monocytes similar to dog/ cat.
    Representative rabbit blood cells - (A) RBCs + platelets, (B) heterophil, (C) lymphocyte, (D) Eosinophil, (E) basophil, (F) monocyte.
  • Guinea pig WBCs
    Kurloff cell = produced by the thymus under oestrogen stimulation. Resembles lymphocyte with round to oval inclusions.
    Neutrophil most abundant cell.
    Same as the other mammals except for the Kurloff cells.
  • Ferret WBCs
    Neutrophils: contain small, pale-red granules.
    Eosinophil: granules rounded and bright red.
    Generally, have higher HCT, HB and RBC counts.
    White cell count generally quite low (3-4 x10^9).
    Ferrets appear to have no blood groups.
  • Reptile erythrocytes and thrombocytes
    Both cell types are Nucleated.
    Similar function to mammals.
    PCV 20-40% in most species.
    Erythrocyte life span up to 800d in some species.
    Polychromasia and reticulocytosis low (<1%).
    May take 4 months for losses to be replenished.
  • Reptile Heterophils
    Predominant cell types.
    Equivalent to mammalian neutrophils.
    Intracytoplasmic fusifrom granules.
    Increase in summer, decrease during hibernation.
    Heterophilia = infection, inflammation, stress.
    Heteropaenia = chronic stress/ disease, severe infection.
    Toxic Heterophils in severe inflammation.
  • Reptile lymphocytes
    Morphology very similar to mammals.
    Lymphocytes generally lowest in winter.
    Lymphopaenia = malnutrition, stress immunosuppression and poor husbandry.
    Lymphocytosis = inflammation, parasitic and viral disease, wound healing, ecdysis.
  • Reptile eosinophils and basophils
    Similar morphology to those of mammals.
    Eosinophils generally lower in summer.
    Eosinophilia = parasites and inflammation.
    Basophils minimal seasonal change.
    Basophilia = parasitic and viral disease.
  • Reptile monocytes and Azurophils
    Azurophils:
    • Unique to reptiles.
    • Similar to monocytes in mammals.
    • Red-purple cytoplasm.
    • More common in snakes.
    Also have monocytes, which are similar to those of mammals.
    Monocytosis and Azurophilia occur with inflammation and granulomatous diseases.
  • Avian Venipuncture - risk factors
    Some important differences to mammals:
    • Veins are generally very superficial.
    • Veins are very fragile and prone to haematoma formation.
    • Post-sampling haemorrhage and haematoma formation is potentially life-threatening.
  • Avian Venipuncture - safe volumes
    Circulating blood volume is approxiately 6-12% of body weight.
    May collect up to 10% of this (i.e. 6-12ml/kg).
    If in poor health take much less!
    • Take into account potential volume lost in haematoma which can be hugely significant in small species e.g. Budgies.
  • Avian Venipuncture - sample preparation

    EDTA - can haemolyse red blood cells in some species (corvids, ostriches, some ducks).
    Lithium Heparin - used for Haemotology and biochemistry in small patients.
    Always make to good quality fresh blood smears.
    Haemotology is usually performed manually since automated techniques are made difficult due to nucleated red blood cells.
  • Avian Venipuncture - restraint
    Inadequate restraint:
    • Injury to patient.
    • Injury to the handler.
    • Possibly fatal haemorrhage.
    Prolonged restraint:
    • Stress
    • Hyperthermia.
    Sedation/ GA with gas:
    • Probably less risk than physical restraint in sick or fractious birds.
    • Reduce haematoma formation by relieving stress and lowering blood pressure.
  • Avian Venipuncture - jugular vein
    Large, accessible vein.
    Right jugular vein usually used as tends to be larger.
    Can use in all species:
    • Easily visualised in most without plucking feathers.
    • Palpation and blind technique in some species (penguin, waterfowl, cranes).
    • Can be difficult to prevent/ stop haematoma.
  • Avian Venipuncture - Ulnar/asilic vein
    Small samples in larger birds.
    Potential to fracture wing if performed conscious.
    Haematomas are common and can be severe.
    How?
    • Bird placed dorsal recumbency.
    • Extend the wing.
    • Wing stabilised with thumb and forefinger.
    • Syringe rested on thumb and advanced into vein.
  • Avian Venipuncture - Medial metatarsal vein
    Very useful in waterfowl and chickens.
    Heavy scaling may be a problem.
    How?
    • Lateral recumbency with lower limb extended caudally.
    • Easy to restrain in towel with feet out.
    • Limb held by assistant similarly to dog/cat.
    • Medial aspect. Above or below joint.
    • Light pressure bandage easily placed to prevent haematoma.
  • Avian cellular origins - thymus
    Located in the neck and consists of 3-8 flattened, pale pink lobes lying along the neck, close to jugular vein.
    T-lymphocyte precursors are produced by stem cells in the embryonic yolk sac and bone marrow and then develop into T-lymphocytes in the thymus.
    Thymus decreases in size at sexual maturity.
  • Avian cellular origins - Bursa of Fabricus

    Unique to birds.
    Is a dorsal diverticulum in the proctodeum.
    Consists of folds of lymphoid tissue.
    Stem cells in yolk sac produce B-lymphocyte precursors which then develop in the bursa.
    Subsequently seeds other lymphoid organs with B-cells.
  • Avian cellular origins - spleen
    Situated on right side of coelom between proventricular and ventriculus.
    Shape varies.
    Not a blood reservoir so is relatively small.
    Aged erythrocytes are phagocytosed.
    Aids in lymphopoiesis and production of antibody.