Vitamin B12 and Folic Acid Deficiency Flashcards
(36 cards)
HAEMATINICS are?
Iron, vitB12 and folate
What vitamins are needed to make blood
Iron, vitB12 and folate
Absence of B12 or folate leads to?
Severe anaemia
B12 IS REQUIRED FOR: (2)
- DNA synthesis
2. Integrity of the nervous system (peripheral and central)
FOLATE IS REQUIRED FOR: (2)
- DNA synthesis
2. Homocysteine metabolism
What type of cells are affected by B12 OR FOLATE DEFICIENCY
ALL RAPIDLY DIVIDING CELLS ARE AFFECTED:
- Bone marrow
- Epithelial surfaces of the mouth and gut
- Gonads e.g. sperm production
- Embryogenesis
Features of vitB12 and folate deficiency? (5)
- Anaemia (MACROCYTIC AND MEGALOBLASTIC)- weak, tired, short of breath
- Jaundice
- Glossitis and angular cheilosis
- Weight loss, change of bowel habit
- Sterility in males
NORMAL RED CELL MATURATION: (4 steps)
- Erythroblast (earliest RBC precursor)
- Normoblast: Early/Intermediate/Late
- Reticulocyte
- Circulating RBC
MEGALOBLASTIC ANAEMIA is defined as….
asynchronous maturation of the nucleus and the cytoplasm in the erythroid series
What is seen in PERIPHERAL BLOOD IN MEGALOBLASTIC ANAEMIA
- Anisocytosis
- Large red cells
- Hypersegmented neutrophils
- Giant metamyelocytes
Where is dietary folate sourced from? When is this a problem
- Fresh leafy vegetables
- Destroyed by overcooking/canning/processing
Reasons for low folate? 3
- Ignorance
- Poverty
- Apathy
Consider alcoholics and elderly people
Physiological and pathological reasons for an INCREASED DEMAND FOR FOLATE: (3+3)
PHYSIOLOGICAL: - Pregnancy - Adolescence - Premature babies PATHOLOGICAL: - Malignancy - Erythroderma Large amount of body SA is inflamed- need folate to replace cells - Haemolytic anaemias
How to diagnose folate deficiency? (2)
- FBC and film
- Folate levels in the blood
How to ASSESS CAUSE OF DECREASED FOLATE: (2)
- HISTORY (diet, alcohol, illness)
- Examination Skin disease/alcoholic liver disease
Consequences of folate deficiency? (3)
- MACROCYTIC, MEGALOBLASTIC ANAEMIA
- Neural tube defects in developing foetus
- Increased risk of thrombosis in association with variant enzymes involved in homocysteine metabolism
What neural tube defects can happen with a folate deficiency
- Spina bifida Spinal column not fully closed off
- Anencephaly No head
- ALL PREGNANT SHOULD WOMEN TAKE FOLIC ACID 0.4MG PRIOR TO CONCEPTION AND FOR FIRST 12 WEEKS
What prophylactic treatment do you give to pregnant women and why
- Spina bifida Spinal column not fully closed off
- Anencephaly No head
- ALL PREGNANT SHOULD WOMEN TAKE FOLIC ACID 0.4MG PRIOR TO CONCEPTION AND FOR FIRST 12 WEEKS to prevent above
What does homocysteine do
involved in converting folate to a useful form and is converted to methionine rapidly when it gets used as it is known to be toxic
High homocysteine levels are associated with (2)
ATHEROSCLEROSIS
PREMATURE VASCULAR DISEASE
- Mildly elevated levels of homocysteine are associated with: (3)
CARDIOVASCULAR DISEASE DEFINITELY
ARTERIAL THROMBOSIS PROBABLY
VENOUS THROMBOSIS PROBABLY
Neurological consequences of B12 deficiency?
- Bilateral peripheral neuropathy
- Subacute combined degeneration of the cord Posterior and pyramidal tracts of the spinal cord
- Optic atrophy
- Dementia
Normal history of a B12 deficient patient?
- Parasthesiae – pins and needles
- Muscle weakness
- Difficulty walking
- Visual impairment
- Psychiatric disturbance
3 common causes of B12 deficiency?
- POOR ABSORPTION COMMONEST CAUSE- because of complex mechanism of absorption which can go wrong in many ways
- Reduced dietary intake:
Stores are large and last for 3-4 years
All animal produce contains B12
Vegans are at risk - Infections/infestations (these can consume B12):
Abnormal bacterial flora (stagnant loops)
Tropical sprue
Fish tapeworm
