haematology - macrocytic anaemia Flashcards
causes of macrocytosis
megaloblastic
nonmegaloblastic
other haematological disease
causes of megaloblastic macrocytosis
B12 deficiency
folate deficiency
cytotoxic drugs
causes of non-megaloblastic macrocytosis
alcohol reticulocytosis liver disease hypothyroidism pregnancy
other haematological disease macrocytosis
myelodysplasia
myeloma
myelproliferative disorders
aplastic anaemia
features of a megaloblastic blood film
hyperhsegmented polymorphs leucopenia macrocytosis anaemia thrombocytopenia with megaloblasts
source of B12
meat and dairy
causes of B12 deficiency
dietary
malabsorption
- stomach
- terminal ileum
malabsorption of B12 in stomach
lack of intrinsic factor produced by parietal cells
pernicious anaemia
post gastrectomy
malabsorption of B12 in terminal ileum
due to ill resection Crohn's bacterial overgrowth tropical sprue tapeworms
clinical features of B12 deficiency anaemia
glossitis
angular cheilosis
irritability
depression
psychosis
dementia
paraesthesiae
peripheral neuropathy
SACD of spinal cord
pernicious anaemia
autoimmune atrophic gastritis
↓
achlorhydria and lack of IF
most common cause of macrocytic anaemia in Western countries
pernicious anaemia
specific tests for pernicious anaemia
parietal cell antibodies (90%)
IF antibodies (50%)
Schilling test
treatment of B12 deficiency
IM hydroxycobalamin
sources of folate
green vegetables nuts yeast liver synthesised by gut bacteria
cannot produce de novo
