Anaemia and haematinic deficiencies Flashcards
What happens when bleeding occurs acutely and chronically?
1) Acutely, loss of red cells, quickly
• Hb concentration remains the same
2) Plasma volume expands to maintain BP –> dilution of red cells
• Hb falls
• MCV remains the same
3) Chronically, iron stores are depleted making fresh red cells
• Iron stores (ferritin) falls
• Hb and MCV may remain relatively normal
4) When iron stores are depleted
• Iron deficient, microcytic, hypochromic red cells are made
What is functional iron deficiency?
Evolutionary advantage to keep iron away from bacteria.
Increased stores in infection/inflammation.
Decreased absorption via hepcidin in enterocyte basolateral membrane.
What is pteroylglutamic acid?
Folate
What are some causes of folate deficiency?
1) Low intake
2) Impaired absorption (crohn’s, coeliac)
3) Increased requirement (pregnancy, haemolysis, inflammation)
4) Increased excretion/loss (dialysis, drugs)
What is cyanocobalamin?
Vitamin B12
What is the Schilling test?
Used to determine how well vitamin B12 is absorbed in the intestinal tract.
What is pernicious anaemia?
Where parietal cells in the gastric mucosa are targeted by an autoimmune response.
Thus intrinsic factor is not produced and vitamin B12 is not absorbed.
This leads to a macrocytic anaemia.
What are acanthocytes? In what conditions can they be present?
A red blood cell that has a spiked cell membrane, due to abnormal thorny projections. Also known as a spur cell.
Found in cases of acute or chronic anemia, hepatitis A, B, and C, hepatorenal syndrome, hypopitutarism, malabsorption syndromes, and malnutrition
What is an echinocyte?
RBCs that have a membrane characterised by many small, evenly spaced thorny projections. (REVERSIBLE)
Also known as burr cell.
Echinocytes can be distinguished from acanthocytes by the shape of the projections, which are smaller and more numerous than in acanthocytes and are evenly spaced. Echinocytes also exhibit central pallor under Wright staining.
What does poikilocytosis mean?
Abnormally shaped erythrocytes
What is sideroblastic anaemia?
Bone marrow produces ringed sideroblasts rather than healthy red blood cells (erythrocytes).
Iron is available but cannot be incorporated it into haemoglobin.
Causes include genetic disorders or indirectly as part of myelodysplastic syndrome which can develop into hematological malignancies (especially acute myeloid leukemia).
