Pathology

• Welcome to Pathology – Blood disorders!

  
• Please tap in with your campus card and take a seat. Settle in and we'll begin in a bit....
• Pathology: Blood Disorders
• Dr Natasha Barrett
• Lecture capture – new!


  Many lecture theatres are now set up to record the slides and audio of lectures as they are delivered (Yuja).
• Any conversations near the microphone will be captured if recording is active ie. any Q&A / discussions.
• Not all staff will be recording lectures.
• Recordings (where available) will not be available immediately.
• Learning Objectives


  • By the end of this session you should be able to:

  Describe several different blood disorders

  • Anaemia (RBCs)
  • Leukaemia (WBCs)
  • Thrombosis (platelets / coagulation)

  Including details of their...

  • Pathophysiology (see A&P notes)
  • Histology
  • Symptoms / signs
  • Diagnosis
  • Treatment / prevention
  • Prognosis
• Blood - Anatomy
• Red blood cells


  Part of blood that supplies oxygen to tissue and cells, and helps remove carbon dioxide
• White blood cells


  Part of blood that helps fight infection
• Platelets and plasma (clotting factors)


  Part of blood that prevents vascular leaking
• RBCs - Anaemia
• Signs and symptoms
• Histology of RBCs


  Blood smear stained with Romanowsky stain:

  • Methylene blue stains nuclei purple
  • No nucleus
  • Eosin (counterstain) stains cytoplasmic proteins pink
  • Full of haemoglobin
  • No mitochondria
  • LOTS! 4-6 x 1012/L
  • Biconcave discs
  • 7-12µm, ~90fL

  
• Pathophysiology


  Physiology (function) of RBCs: Transport of oxygen (bound to haemoglobin) and carbon dioxide around the body

  Pathophysiology: When the physiology goes wrong resulting in disease or disorders ie. Inability to transport sufficient O2 / CO2 around the body
• Anaemia


  Reduced haemoglobin concentration in the blood

  • Reduces the oxygen carrying capacity of blood
  • Common condition, affecting 10% of women and 2-5% of men
  • Several different causes / classifications
  • Usually low haematocrit
  • May or may not cause low RBC count
  • May cause small pale RBCs
• Common Causes of Anaemia


  • Acute bleeding (trauma, surgery)

  Chronic bleeding (GI, heavy menstruation)

  Iron deficiency (dietary, malabsorption, pregnancy)

  Folate / Vitamin B12 deficiency (dietary, malabsorption)

  Premature destruction of RBCs (haemolysis eg. Sickle cell)
• Signs and Symptoms of Anaemia


  • Shortness of breath

  Tachycardia

  Pallor

  Fatigue
• Diagnosis of Anaemia
• Diagnosis of Anaemia


  • FBC
  • Anaemia Y/N
  • Hb concentration <120g/L
  • Cause / class
  • RBC count
  • Size of RBCs
  • Colour of RBCs

  
• Treatment of Anaemia


  Depends on cause

  • Stop / address any bleeding
  • Iron rich foods, iron supplements, iron injections
  • Folate / B12 rich foods, supplements, B12 injections
  • Blood transfusion

  Prognosis – depends on the cause
• A person with a normal RBC count can still be anaemic
• Anaemia causes tachycardia
• If you are anaemic you must need more iron
• WBCs - Leukaemia
• Histology of WBCs


  5 types of WBC

  • Fewer / larger than RBCs ~24μm
  • Romanowsky stain:
  • Methylene blue stains nuclei purple
  • Different shaped nuclei
  • Eosin stains cytoplasm pink
  • Granulocytes contain differently staining granules
• Functions of WBCs (physiology)

  Neutrophils: Migrate out of blood into tissues where needed. Elevated in bacterial infection, stress, exercise.

  Lymphocytes: Sit in lymph nodes to screen lymph. Elevated in viral infection.

  Monocytes (macrophages in tissues): Clear cell debris. Elevated in infection, inflammation, tissue damage.

  Eosinophils: Role in allergy, intestinal parasites.

  Basophils: Role in allergy.
• Pathophysiology


  When the physiology goes wrong (too much or too little).
• Pathologies of WBCs


  • Deficiencies of WBCs eg. Neutropenia

  Autoimmune disorders (separate lecture)

  Infections (separate lecture)

  Leukaemia – cancer of the WBCs
• Leukaemia


  Uncontrolled growth of one WBC type in the bone marrow

  in affected WBC type

  Bone marrow failure (over crowding)
• 4 main classes of leukaemia


  • AML – acute myeloid leukaemia

  CML – chronic myeloid leukaemia

  CLL – chronic lymphoid leukaemia

  ALL – acute lymphoblastic leukaemia
• Acute leukaemia – many immature WBCs
• Chronic leukaemia – many maturing or mature WBCs
• Common Causes of Leukaemia


  • Usually unknown cause

  Occasionally chemicals, radiation, viral or genetic
• Signs and Symptoms of Leukaemia


  • Overcrowding of the bone marrow causes...

  Anaemia (SOB, fatigue)

  Leukopenia (recurrent infections)

  Thrombocytopenia (bleeding)
• Diagnosis of Leukaemia
• Diagnosis of Leukaemia


  • FBC

  affected WBC type

  other WBCs

  RBCs

  platelets

  Bone marrow biopsy

  immature WBCs

  Histology of WBCs

  Possibly enlarged nuclei (immature blast cells)
• Treatment of Leukaemia


  • Chemotherapy

  Bone marrow transplant