Vit B12 and folate deficiency Flashcards
Define Vitamin B12 & Folate deficiency
Deficiency in vitamin B12 and folate that results in macrocytic and megaloblastic anaemia
Aetiology of folate deficiency
Ignorance, poverty, apathy - Often present in elderly alcoholics
Alcoholism
Increased physiological demand (pregnancy, adolescence, prematurity, lactation)
Pathological demand (malignancy, erythroderma, haemolytic anaemia)
Small intestine disorders (tropical sprue, coeliac, intestinal resection)
Medications e.g. sulfasalazine, trimethoprim, methotrexate, pyrimethamine, anticonvulsants
Thrombosis due to enzymes invovled in homocysteine metabolism
Aetiology of B12 deficiency
(Normal absorption in the duodenum and terminal ileum of the SI via intrinsic factor)
Reduced intake: vegans and vegetarians
Poor absorption: reduced intrinsic factor, gastric atrophy, pernicious anaemia
Diseases of the small bowel: Crohn’s, coeliac disease, surgical resection
Infections: H. pylori, Giardia, fish tapeworm
Drugs: metformin, PPIs, oral contraceptive
Symptoms of folate deficiency
Anaemia: fatigue, weak, tired, SOB, dizzy
Weight loss and changes in bowel habit (diarrhoea)
Headache
Loss of appetite
Sterility
Developing foetus - spina bifida, anencephaly
Symptoms of B12 deficiency
Anaemia: fatigue, weak, tired, SOB Weight loss and changes in bowel habit Sterility Loss of sensation in the lower extremities Paraesthesiae in glove and stocking distribution Muscle weakness Visual impairment Psychiatric disturbances Ataxia
Signs of folate deficiency
Jaundice Glossitis and angular cheilosis Signs of alcoholic liver disease Signs of skin diseases (exfoliative dermatitis) Tachycardia and tachypnoea Anaemia: Pallor Petechiae Painful swallowing
Signs of B12 deficiency
Bilateral peripheral neuropathy Optic atrophy Dementia Absence of reflexes Upgoing plantar response Positive Romberg's test Petechiae Glossitis and angular cheilitis Anaemia: pallor
Investigations for folate deficiency
FBC: Macrocytic anaemia | low haematocrit | elevated MCH | thrombocytropenia | neutropenia
Peripheral blood smear: Anisocytosis | macrocytosis | hyper-segmented neutrophils | giant metamyelocytes/megamyelocytes
Reticulocyte count: low
Serum folate: low
Red cell folate: low
Serum B12: normal Serum LDH: elevated Serum unconjugated bilirubin: elevated Serum iron panel: elevated serum iron, ferritin, transferrin Plasma homcysteine: elevated
Investigations for B12 deficiency
Anisocytosis | macrocytosis | hyper-segmented neutrophils | giant metamyelocytes/megamyelocytes
Serum B12: low
Reticulocyte count: low
Intrinsic factor antibodies: ?pernicious anaemia
Anti-parietal cell antibodies: ?pernicious anaemia
Breath test for bacterial overgrowth: ?H. pylori
Homocysteine and methylmalonic acid (MMA)
