Anaemias 2

What are the types of anaemia?

  1.   Iron-Deficiency Anaemia

Importance: iron is critical to the formation of red blood cells

Cause: decreased intake of iron, increased demand, excessive blood loss

Red blood cell (RBC) state: microcytic and hypochromic

NOTE: ingested iron moves into the plasma where it binds to transferrin, which is then absorbed into the liver or bone marrow. It is the recycling of red blood cells in the spleen that returns this iron into the bloodstream.

  2.   B₁₂ and Folate Deficiency Anaemia (Pernicious Anaemia)

Importance: vitamin B₁₂ and folic acid play a role in red blood cell maturation

RBC state: microcytic (megaloblastic) and low hematocrit

  3.   Aplastic Anaemia

Cause: failing haemopoietic stem cells, decreasing levels of red blood cells, white blood cells and platelets due to radiation, chemotherapy, drugs, viruses and autoimmune diseases

RBC state: normocytic, normochromic and low count

  4.   Post-Hemorrhagic Anaemia

Cause₁: severe acute blood loss
RBC state₁: normocytic, normochromic, low hematocrit

Cause₂: chronic blood loss
RBC state₂: microcytic and hypochromic

  5.   Haemolytic Anaemia

Cause: chronic increased destruction of red blood cells with a shorter life span

RBC state: increased reticulocyte count, splenomegaly

Sickle Cell Anaemia

Cause: mutation in the gene coding for the ϐ-globin chain

Characteristics: abnormally structured haemoglobin, rigid and deformed red blood cells, 'sickle shaped' red blood cells when deoxygenated

Consequences: vessel occlusion → tissue ischemia, infarction and gangrene, chronic hyperbilirubinaemia (jaundice skin and eyes)

Thalassemia

Cause: mutation in gene coding for synthesis of ɑ or ϐ global chains

Characteristics: less haemoglobin being produced → increased destruction of red blood cells

Types: thalassemia minor (heterozygotes: next to no symptoms, protective against malaria), thalassemia major (homozygotes: severe, life-threatening form)

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