Flashcards in MACROCYTIC ANAEMIA Deck (29):
What is the normal range for mean cell volume?
What type of macrocytic anaemia does folate or B12 deficiency cause?
Megaloblastic anaemia (right shift)
What processes are affected by folate or B12 deficiency?
What is the daily requirement of vitamin B12?
Where is vitamin B12 absorbed?
What must be present for vitamin B12 to be absorbed?
Where is intrinsic factor excreted?
Parietal cells of the stomach.
What is the most common cause of vitamin B12 deficiency in the UK?
What is the underlying mechanism of pernicious anaemia?
Autoimmune gastritis where autoantibodies attack the parietal cells leading to a reduction in intrinsic factor.
Is pernicious anaemia more common in males or females?
What is the peak age of onset for pernicious anaemia?
What diseases are associated with pernicious anaemia?
Vitiligo - patchy whiteness of the skin
What is the daily requirement of folate?
Where is folate absorbed in the intestine?
Upper small intestine
How long do body stores of folate usually last for?
What disease is especially associated with folate deficiency?
What are the clinical features of megaloblastic anaemia caused by a vitaman B12 or folate deficiency?
May present with signs of congestive heart failure
What does the blood film of someone with anaemia related to vitamin B12 or folate deficiency look like?
Hypersegmented neutrophil neuclei
Low white cell or platelet count
What are the characteristics bone marrow features of megaloblastic anaemia?
Other than low Hb, what might a blood test of someone with megaloblastic anaemia show?
Raised unconjugated bilirubin
Raised serum lactic dehydrogenase
Raised serum homocysteine
Parietal cell antibodies
Intrinsic factor antibodies
Why is jaundice associated with megaloblastic anaemia?
Increased destruction of the red cell precursors in the marrow
Other than anaemia, what other effects are there from a vitamin B12 or folate deficiency?
Neural tube defects
Epithelial changes - such as glossitis
What is the most common cause of raised MCV of red blood cells (macrocytosis) in the UK?
Alcohol - even quite small amounts and not necessarily associated with liver disease
What are the causes of raised MCV of red blood cells?
Megaloblastic anaemia (B12 and folate)
Pregnancy and neonatal period
Changes in plasma protein (eg paraproteins associated with myeloma)
Drugs - hydroxyurea and azathioprine
Benign familial macrocytosis
Other than blood tests, what investigations would you do with someone who presented with megaloblastic anaemia?
Bone marrow examination
Radioactive vitamin B12 absorption study - with and without intrinsic factor
Endoscopy - to confirm atrophic gastritis or exclude gastric carcinoma
What are the causes of megaloblastic anaemia?
Congenital intrinsic factor deficiency
Congenital selective malabsorption
Drugs - anticonvulsants, sulphasalazine
What is the medical treatment of vitamin B12 deficiency?
Initial treatment is injections of hydroxycobalamin 1 mg every 3-4 days, followed by 4 injections a year for life.
What is the medical treatment of folate deficiency?
Folic acid 5 mg daily for 4 months
Those with severe haemolytic anaemia should continue to have this dose once a week.