Blood Cell Abnormalities Flashcards
What is anaemia?
The reduction in Hb in a given volume of blood below what is expected in a healthy person
What is microcytic anaemia?
RBC size is reduced- usually also hypochromic
What are common causes of microcytic anaemia?
Defect in haem synthesis
Iron deficiency
Anaemia of chronic disease
Defect in globin synthesis (thalassemia)
What are causes of iron deficiency?
Increased blood loss Insufficient intake (dietary/ malabsorption) Increased requirement (pregnancy, infancy)
What is macrocytic anaemia?
RBC increased in size- usually also polychromatic
Result of abnormal haemopoiesis so red cell precursors continue to generate Hb and other cellular proteins but fail to divide normally
What is megaloblastic erythropoiesis?
Delay in maturation of nucleus whilst cytoplasm continues to mature and cell continues to grow.
Megaloblasts often seen in blood marrow not blood film
What are common causes of macrocytic anaemia?
Lack of B12 or folate
Liver disease and ethanol toxicity
Haemolytic anaemia (increased reticulocytes)
Pregnancy
Use of drugs interfering with DNA synthesis
Major blood loss with inadequate iron stores
What are causes of normocytic anaemia?
Recent blood loss- GI haemorrhage, trauma
Failure in production of RBCs- early stages if iron deficiency, bone marrow failure or suppression, bone marrow infiltration e.g. leukaemia
Pooling of red cells in spleen- hypersplenism e.g. liver cirrhosis, splenic sequestration in sickle cell anaemia
What are stages of iron depletion?
Iron depletion: storage iron reduced or absent
Iron deficiency: low serum iron and transferrin saturation
Iron deficiency anaemia: low haemoglobin and haematocrit
What are clinical features of iron deficiency anaemia?
pallor, fatigue, breathlessness, impaired development in children
What are common causes of anaemia of chronic disease?
Rheumatoid arthritis Autoimmune disease Malignancy Infectors such as TB and HIV Kidney disease
What’s the pathophysiology of anemia of chronic disease?
cytokines such as TNF and interleukin alpha in chronic disease lead to decrease in erythropoietin production and prevents normal flow of iron from duodenum to RBCs
What are laboratory clues of ACD?
High ferritin
Low transferrin
C-reactive protein is high
Erythrocyte sedimentation rate is high (unlike iron deficiency)
What is polycythaemia?
Too many red cells in circulation- Hb, RBC and Hct all increased
Pseudopolycythaemia = reduced plasma volume
True polycythaemia = increase in total red cells in circulation
What are causes of polycythaemia?
Blood doping or over transfusion
Appropriately increased erythropoietin- e.g. result of hypoxia
Inappropriate erythropoietin synthesis/ use- e.g. from renal tumour secretion
What is polycythaemia vera?
Independent of erythropoietin
Intrinsic bone marrow disorder (myeloproliferative neoplasm) leading to hyperviscosity (thick blood)
This can lead to vascular obstruction and venous or arterial thrombosis
Drugs given to reduce bone marrow production of RBCs or blood can be removed to reduce viscocity
What is chronic leukaemia?
Benign- will last a while before death
What is acute leukaemia?
Malignant- leads to death in short amount of time and is aggressive
What is lymphoid leukaemia?
affects B, T or NK lineage
What is myeloid leukaemia?
Affects a combination of granulocytic, monocytic, erythroid or megakaryocytic lineage
What is leukaemia?
Cancer of the blood, bone marrow disease
What are causes of leukaemia?
Results from series of mutations in single lymphoid or myeloid stem cell
Mutations leads to progeny of cell to show abnormalities in proliferation, differentiation and survival- leads to steady expansion of leukemic clone
What is acute lymphoblastic anaemia?
Increase in very immature cells (lymphoblasts)
Bone marrow is infiltrated by immature lymphoblasts resulting in impaired haematopoiesis
What are causes of acute lymphoblastic anaemia?
Causes usually unknown, sometimes mutagenic drugs or exposure to irradiation or chemicals in utero, possibly delayed exposure to pathogen
