Vitamin B12 and Folate deficiency

Question 1

define vitamin B12/ folate deficiency?

Answer 1

Having insufficient vitamin B12/ folate to meet demands

Question 2

summarise the epidemiology of vitamin B12 deficiency?

Answer 2

peak age= 60 years

vegans have higher risk of dietary B12 deficiency

preg- need to be on folate supplements

Question 3

where is B12 found and describe its absorption?

Answer 3

found in meat and animal protein foods

absorption occurs in terminal ileum and requires intrinsic factor ( produced by gastric parietal cells)

Question 4

what is pernicious anaemia?

Answer 4

autoimmune condition->Involves gastritis, atrophy of all layers of the body and fundus of the stomach and loss of normal gastric glands, parietal and chief cells=> lack of IF

accounts for 80%of megaloblastic anaemia due to impaired vitamin B12 absorption

Question 5

what are the causes/ risk factors of B12 deficiency

Answer 5

gastric- gastrectomy, atrophic gastritis- loss of IF production

inadequate intake ( vegan) - stores last 3-4 years

intestinal- malabsorption, ileal resection, crohns affecting terminalileum,tropical sprue

drugs- colchicine, metformin

Question 6

what are the causes/risk factors of folate deficieny?

Answer 6

less intake
▪ Anorexia – diet: broccoli, Brussels sprouts, asparagus, peas, chickpeas and brown rice
▪ Alcoholics
Elderly

increase demand

• pregnancy
• malignancy
• chronic inflammatory
• chronic haemolytic anaemia
• haemodialysis

decreased absorption

• jejunal disease ( coeliac’/topical sprue/ whipple’s
• SI resection

○ Meds
▪ Phenytoin (anti-epileptics)9
▪ Trimethoprim (AB)
Sulphasalazine

Question 7

what are the typical symptoms of anaemia?

Answer 7

fatigue
lethargy 
dyspnoea
faintness 
palpations
headache

Question 8

What are the B12 symptoms?

Answer 8

typical anaemia symptoms 
a pale yellow tinge to your skin 
mouth ulcer 
neurological symptoms- parasthesia-= glove and stocking 
- numbness 
- cognitive changes 
- visual disturbances 
- rombergs positive- positive rombergs test ( feeling unsteady when eyes closed) indicated a proprioceptive issue

joint position and vibration sense lost first then distal paras

▪ upper motor neuron signs typically develop in the legs, classically extensor plantars - positive babinski reflex, brisk knee reflexes, absent ankle jerks (dorsal + lateral columns affected)
▪ Depression
Irritability

Question 9

what is B12 fundamental for the maturation of?

Answer 9

RBC maturation

Question 10

what are the symptoms of a folate deficiency?

Answer 10

symptoms related to anemia

diarrhoea

headache

Question 11

how long do B12 reserves last?

Answer 11

3-4 years

Question 12

what are the signs of B12 deficiency?

Answer 12

-pallor
-heart failure
-glossitis
-angular stomatitis
-neuropsychiatric: Irritability, dementia, depression
- neurological
- subacute combined degeneration of the spinal cord
peripheral neuropathy
-upper motor neuron signs typically develop in the legs, classically extensor plantars - positive babinski reflex, brisk knee reflexes, absent ankle jerks (dorsal + lateral columns affected)

Question 13

what are the investigations for a B12 deficiency?

Answer 13

• There is NO gold standardy
• Measurement of serum B12/ folate is not very accurate or reliable
• FBC and blood film
○ Elevated MCV, low haematocrit
○ Hypersegmented neutrophils 
○ Oval macrocytes 
○ Circulating megaloblasts 
Low corrected reticulocyte index

Question 14

what investigations would you consider for pernicious anaemia?

Answer 14

anti-intrinsic factor antibodies

anti-parietal cell antibodies

schilling test: increased excretion of B12 with added intrinsic factor

Question 15

what are the other new tests for B12 deficiency?

Answer 15

plasma total homocysteine, plasma methymalonic acid, holotranscobalamin