AGEP 2 Clinical Haematology 1 24-25 PDF

Clinical Haematology 1 Session ID: & Introduction to Task EmiB TurningPoint mobile...

Clinical Haematology 1 Session ID: & Introduction to Task EmiB TurningPoint mobile App, or AGEP 2; Animal Systems and Professional Life 2 www.ttpoll.eu Emi Barker BSc (hons) BVSc (hons) PhD PGCertTLHE DipECVIM-CA FRCVS RCVS Recognised and EBVS® European Veterinary Specialist in Small Animal Internal Medicine Clinical Lead in Infectious Diseases [email protected] https://eclinpath.co m/ Intended learning outcomes 1. Understand the concepts behind the laboratory assessment of the erythrocyte 2. Recognise common red blood cell (RBC) abnormalities, including terminology and clinical significance 3. Be aware of other auxiliary diagnostic tests used in the assessment of RBC abnormalities NB: erythrocyte = red blood cell Haematology  This series will be primarily canine- / feline-based – with other species indicated where appropriate Where are red blood cells primarily made? A. Bone marrow B. Liver C. Spleen D. Thymus To understand abnormal, you need to understand normal…  Erythropoiesis = production of erythrocytes – Typically, in bone marrow within the medullary cavity of larger bones (of axial and appendicular skeleton) – Can also occur at extramedullary sites at times of increased demand or if the bone marrow is failing (e.g. liver, spleen) RBC production  Erythropoietin (EPO) = main stimulus for RBC production 5-7 1-2 days days RBC structure  Biconcave disk (in health) – Increased surface area for oxygen diffusion – Flexible – to pass through smaller vessels  High concentration of cytoplasmic haemoglobin (iron-containing metalloprotein) – Carries oxygen RBC lifespan  Anucleate (in mammals) – no capacity for repair in circulation  Senescent (end of life) RBC 70 days (cat) – Removed in spleen 110 days – Or haemolyse (dog) 145 days (horse) What tube do we collect samples for haematology into? A. Citrate B. EDTA C. Heparin D. Oxalate fluoride E. Serum / clot  Red blood cell parameters Platelet parameters White blood cell parameters Manual comment Beware the interference from artefacts…  Clots  Platelet clumps  Macroplatelets  Cell (RBC, leukocyte) Example of a agglutination macroplatelet  Nucleated RBC  Heinz bodies  Lipaemia  Delay in sample handling  haemolysis and cell swelling Evaluating RBC RBC mass RBC indices Some analysers also  Hb, RBC, and MCV = measured by the analyser provide RBC distribution – HCT, MCH, and MCHC are calculated width (RDW) and reticulocyte count /  Limitations indices – Risk of artefact – No automated machine can evaluate morphology – MCH, MCV, and MCHC are averages Evaluating RBC – packed cell volume (PCV)  Percentage of red cells in a volume of blood  Manual technique Plasma – Centrifuged whole anti-coagulated blood – RBC read as a % of column – Different to haematocrit! Buffy coat  Also permits: – Buffy coat assessment Packed RBC – Plasma colour evaluation (haemolysis, jaundice, lipaemia) – Plasma total proteins measurement (using refractometer) Evaluating platelets  More on this in future lectures Evaluating white blood cells (WBCs) Main parts of a blood smear Base or head Monolayer Feathered edge Blood smear examination 1. Stain the slide (e.g. modified Wright’s; Diff-Quik) 2. Use oil immersion 3. Start with the feathered edge – Platelet clumps – Atypical cells 4. Review the monolayer (battlements) – RBC morphology – Platelet estimation 5. Review the lateral edge – WBC (count, morphology, 100-cell differential) NORMAL ‘normocytic, normochromic’ Anisocytosis  Variability in cell size  Why? – Macrocytosis? – Microcytosis? – Both?  Is there also polychromasia? – Macrocytosis with polychromasia indicates RBC regeneration – Erythroid maturation  progressively smaller cells Macrocytes and microcytes  With polychromasia = regeneration  Without polychromasia  FeLV (cat)  Familial macrocytosis (e.g. Toy / Mini Poodles)  Common laboratory artefact (↑Na+; ↑glucose; excess EDTA; storage)  Iron deficiency (+/- hypochromasia)  Absolute  Relative (liver disease inc. congenital portosystemic shunts. Polychromasia  Variability in cell colour  Due to increased presence of immature RBC (larger, ’bluer’) (‘polychromatophils’)  More notable in some species e.g. dogs Nucleated red blood cells (nRBC) and Howell-Jolly bodies  Retained – Nuclei (nRBC) – Nuclear material (H-JB)  Most commonly seen with regeneration  In the absence of regeneration – Lead poisoning – Splenic disease / removal – Bone marrow disease – Heat stroke What species NORMALLY have nucleated RBC? A. Birds and reptiles B. Horses and donkeys C. Lagomorphs and rodents D. Sheep and cattle Hypochromasia  RBC have less haemoglobin than normal  Typically seen associated with – Iron deficiency anaemia (e.g. severe parasitism; gastrointestinal blood loss;) – And copper deficiency (farm animals)  Often accompanied by poikilocytosis (‘basket’ term for abnormal RBC shape) and microcytosis Schistocytes  RBC fragments  Evidence of shear injury – Vascular neoplasia (e.g. haemangiosarcoma, common in spleen or liver) – Disseminated intravascular coagulopathy – Iron deficiency anaemia (cells are more fragile) – Glomerulonephritis – Heartworm – Portosystemic shunts Acanthocytes, keratocytes, & blister cells Acanthocytes  RBC with large, blunt-ended projections  Seen in liver disease, lipid disorders, and alongside shearKeratocytes and injury blister cells  evidence of shear injury Echinocytes (crenated RBC)  Common artefact  If real – then usually seen alongside other shear-injury related changes Sometimes elliptical RBC are normal! (and, therefore, not considered poikilocytes!) Spherocytes and ghost cells  Seen with certain types of anaemia – More on this is session 2…  Spherocytes – Same volume / smaller surface area  no central pallor Ghost – More challenging to recognise in cats cell Spherocyt es Red blood cell oxidative injury  Heinz bodies – Oxidation of Hb (-SH chain)  non-functional Hb – Pushed to edge of cell = Heinz body – Species susceptibility varies  Cats > horses > dogs  Other evidence of oxidative injury may also be present – E.g. methaemoglobinaemia, eccentrocytes  Causes – Toxicity - Allium spp. (onions, garlic etc. *baby food*); zinc; paracetamol; naphthalene (moth balls); others – Some diseases in cats (diabetes mellitus; lymphoma; hyperthyroidism) New methylene blue (NMB) stain Common, but non-specific, changes  Codocytes (target cells)  Commonly seen with regenerative anaemia or hypochromasia Inclusion bodies Can you name that infectious agent? A. Anaplasma spp. B. Babesia spp. C. Dirofilaria spp. D. Ehrlichia spp. E. Leishmania spp. Introduction to Clinical Haematology task TASK - Intended learning outcomes 1. Apply knowledge, recognise normal and abnormal clinical haematology results 2. Interpret haematology results to determine the likely aetiology 3. Suggest further diagnostic tests to construct a differential diagnosis 4. Apply haematological principles to predict likely findings  You are expected to integrate and apply your existing knowledge alongside that acquired during the clinical haematology teaching  Task material can be found alongside the Clinical Haematology 1 / Intro to Task section on Blackboard MUST DO Tasks  Online Blackboard task (automated Blackboard register) – A series of Blackboard quizzes – relating to clinical cases – Analyse and interpret haematology results and answer questions  The focus of the task is the clinical haematology findings  Other diagnostic results have been included only for clinical context and interest – Use allocated study time, to work INDIVIDUALLY through ALL the cases – You should complete ALL the tasks by 5pm, Wednesday 5th February  Attendance at the LIVE task review session on Friday 7th February – The cases will be wrapped-up (also an opportunity to ask/review other aspects relating to clinical haematology) TASK  Five quizzes (1x analytical aspects of clinical haematology; 4x case studies) – All quizzes allow unlimited attempts – They can be saved and closed at any time – You need to answer each question, before progressing to the next  Each case study/scenario has only ONE disease process that explains ALL the clinical and haematological findings – You will learn to integrate comorbidities later in the course  On completion of each quiz, you will be given a summary of your answers and feedback Any Questions or Feedback? If you have any questions relating to this series of lectures – please post to the relevant padlet (chances are someone else is thinking the same thing!). Feedback is also gratefully received – things to improve, things you would like more of, things that did or didn’t work well – either anonymously on the padlet or feel free to email if you have specific queries [email protected] https://uob.padlet.org/emibarker/emi-barker-s-24-25-root-padlet-30nns46t9hq6p8n8