Haematology: introduction to blood cells Flashcards
Composition of blood
Blood which is composed of plasma (-55%) and the cellular elements which are:
- The erythrocytes (RBC’s)-45%
- The Leukocytes (WBC’s) and platelets (thrombocytes) – 1%
Erythrocytes contain and function
Contain haemoglobin
Function in the transport of O2 and CO2
Centrifuged whole blood the sample
Anti-coagulated sample e.g. EDTA to chelate Ca2+
Normal blood cell production –
- Fetal: yolk sac
- Post natal – long bones (femur and humerus)
- Adult – axial skeleton
Bone Marrow
• 75% of marrow for WBC
• 25% of BM for Red cells
Erythroid/Granuocyte Ratio 1:3 (increased in consumption or loss of RBC)
How are cells produced?
Multi-potential hematopoietic stem cells
• Common myeloid progenitor
• Common lymphoid progenitor
Common myeloid progenitor produces
Thrombocytes Erythrocytes Mast cells Myleblasts: • Basophil • Neutrophils • Eosinphils • Monocyte → macrophage
Common lymphoid progenitor produces
Natural killer cells T lymphocytes (cell mediated immunity and also “help” B cells) B lymphocytes ( humoralimmunity)
Lymphoid tissue found in
- Bone marrow
- Thymus
- Tonsils and adenoids
- Spleen
- Lymph nodes
- Gut associated lymphoid tissue (GALT) e.g. tonsils, appendix, payers patches
- Lymphatic channels
- Blood – 2% of total body lymphocytes
- Thyroid, parotid etc.
Lymph node function
Act as a filter to remove bacteria, wiruses, and foreign particles
Problems with blood cells list
- Myeloid or lymphoid
- Too many cells (cythaemia, cytosis – “reactive or neoplastic/clonal)
- Lymphadenopathy – “reactive or neoplastic”
- Hepatosplenomegaly
- Clonal plasma cells (Myeloma, MGUS, plasmacytoma)
- Too many cells (cytopenia)
- Dysfunction
What does the full blood count measure:
Red cells
Platelets
White cell count
WCC: differential e.g. neutrophils
Red cells looking at
Concentratino of haemoglobin: Hb Red cell to plasma ratio: Hct or PCV (pack cell volume) Cell numbers (RBC) Cell size (MCV) Amount of Hb/RBC (MCH, MCHC)
Platelet normal range
150-4000 x 109/l
WCC normal range
4-11 x 109/l (4-11)
Neutrophils range
2-7.5 x 109/l
Lymphocytes range
1.0-4.0 x 109/l
Haemoglbin
Male: 130-180 g/L
Female: 115-165 g/L
Haematocrit
Male: 42%-54%
Female: 38%-46%
RBC count
Male: 4.7-6.1 million cells/mcL
Female: 4.2-5.4 million cells/mcL
Haematocrit definition
Ratio of red cells to haemoglobin Contents: • 57% plasma • 1% buffy coat – WBC • 42% Hct (PCV)
MCV indicates and good starting point for
Mean cell volume (MCV)
Indicates the Red cell volume (size)
Normal range 80-100 fl
Good starting point for the evaluation of anaemia
MCV can be
Microcytic (100 fl)
Microcytic anaemia differentials
Iron defiency IDA (Chronic bleeding) Chronic disease Thalassemias Hemoglobinopathies Sideroblastic anaemia
Normocytic anaemia differentials
Chronic disease Acute blood loss Hemoglobinopathies Primary marrow disorders Combined defiencies Haemolysis Renal failure
Macrocytic anaemia
Megaloblastic anaemia Liver disease/ alchohol Metabolic disorders Marrow disorders Reticulocytosis Drugs
Mean cell haemoglobin (MCH) and Mean cell haemoglobin concentration (MCHC) reflect
- Both the MCH and MCHC reflect Hb content of RBC
- MCH – 27.0-32.0 pg. Increased on macrocytosis (Large RBC)
- MCHC – 32.0-36.0 g/dL. Increased in spehrocytosis
- Both are reduced in iron defiency and thalassaemia
Reticulocyte count use for
• Investigation of anaemia
Reticulocytes increased indicates
- RBC production appropriately increased
- Reduced survival (Haemoloysis or bleeding)
- LDH, Bili, blood film, haptoglobins can help distinguish
If reticulocytes reduced
• Problem with production
Peripheral blood film usefulness depends on
Clinical information provided on request
May direct further investigations
Asess red cell, platelet and white cell, number, size, colour, morphology
Any abnormal circulating cells?
Red cell morphology example
Sickle cell anaemia
White cell morphology example
Dysplastic neutrophils
Platelets morphology example
Abnormally large platelets
Abnormal circulating cell example
Burkitts lymphoma cells
APML blasts
FBC changes may be secondary to:
Physiological
Inherited
Acquired
Physiological example
Pregnancy
Infancy
Ethnicity different normal ranges
Inherited examples
Anaemia: • Hb • Enzyme • Membrane • Bone marrow
Acquired examples
Infection (viral, bacterial, protozoal) Neoplastic (haem or non haem) Vascular (bleeding, infarction) Inflammatory, Immune Trauma (e.g. surgery) Endocrine 9thyroid, cortisol, pituitary) Drugs Metabolic (B12, folate, iron, liver, renal, alcohol) Degenerative (MDs), Dietary
Too many cells: Clonal/neoplastic
Lymphoid progenitor: • ALL (immature cells) • CLL, Lymphomas, MM (mature cells) Myeloid progenitor: • AML (immature cells) • Myeloproliferative disorders
Acute leukaemias Types
Myeloid or lymphoid
Proliferation or immature cells
Differentiation block
Acute leukaemias Symptoms
Marrow failure:
- anaemia
- Thrombocytopenia (bleeding)
- Infection (neutropenia)
- Patients have a relatively short history and are often unwell
Myeloproiferative neoplasm Characterised by
Excessive proliferation of terminally differentiated myeloid cells (normal differentiation) – somatic acquired mutations in haemopoitic stem cells
Myeloproiferative neoplasm Lead to
Cytokine independent unrestricted growth
Myeloproiferative neoplasmPatients present
Often well and asymptomatic therefore incidental findings
Myeloproiferative neoplasm Types
Platelets: essential thrombocytthaemia ET
Red cells: Polycythaemia, rubra Vera, PRV
Granulocytes: Chronic myeloid, leukaemia, Ph+ BCR/ABL +
Myeloproiferative neoplasm Mutation associated
JAK2 V617F
Primary haematological cause
Lymphoid clonal expansion Lymphoproiferative – • Lymphoma • Leukaemia (common present with lymphocytosis or lymphadenopathy or both
Lymphadenopathy causes
Lymphoma
Infection (viral e.g. HIV/EBV, bacterial e.g. TB)
Neoplatic (haem or non haem e.g. Ca)
Inflammatory (e.g. sarcoid, SLe)
Clinically divide into
Localized or generalized
→ if localized look for cause (infection, inflammation, malignancy) – need some idea which lymphoid groups drain what.
Lymphoproliferative (clonal problems
Leukaemia → bone marrow (acute vs chronic) Lymphoma → LNs> bone marrow • Hodkins • Non hodkins High grade vs low grade
Symptomatic Myeloma: Acronym
CRABI C – hypercalcaemia R- renal dysfunction A – anaemia B – bone – lytic lesions, fractures, osteoporosis I – Infection
Symptomatic Myeloma: Asymptomatic Myeloma
No CRABI
AND ether
>-10% plasma cell sin bone marrow
OR > 30 g/ paraprotein
Symptomatic Myeloma: MGUS
<30 g/l paraprotein
AND no CRABI
1% per year progress to Myeloma. More likely. More likely if high level PP, non IgG (IgM, IgA, IgE or IgD) and abnormal SFLC
Thrombocytopenia
- Repeat the test, look at previous results and ask for a blood film.
- Take a careful drug history
- Risk factors for HIV and hepatitis C
- If a patient is well, has no other abnormal clinical or laboratory findings then likely immune thrombocytopenia is the commonest cause
Risk of bleeding is not based on
- Platelet count alone; also consider age, co-morbidity, mandated anticoagulation, risk of trauma and any need for surgery
- Spontaneous bleeding/bruising unusual unless platelets <30 x 109/l
Thrombocytopaenia spurious causes
- Large platelets
- Platelet clumping
- Fibrin strand
- Platelet Satelitism
Neutropenia: Definition
<1.5 x 109/l
Neutropenia: African patients neutrophil numbers normal
<1x109/l (Physiological “ethnic” neutropenia
Neutropenia: Risk of infection determined by
Severity and cause of neutropenia
Mild 1-1.5
Moderate 0.5-1
Severe <0.5
Neutropenia: Neutropenia increases risk of
Bacterial
Suprative infections
Not parasitic or viral infections
