Vitamin deficiencies

Question 1

Where are the vitamins absorbed?

Answer 1

• A, B1 (thiamine), B6 (pyridoxine), E and K are absorbed in the small intestine
• B2 (riboflavin) is absorbed in the PROXIMAL small intestine
• D, folic acid (B9) and nicotinamide (B3) are absorbed in the jejunum
• C is absorbed in the proximal ileum
• B12 is absorbed in the terminal ileum

Question 2

Which vitamins are fat-soluble? Thus, what it the aetiology of their deficiency?

Answer 2

A, D, E and K are fat soluble, so deficiency is likely if there is fat malabsorption.

Question 3

What is the disease associated with Vitamin A deficiency?

Answer 3

Xerophthalmia

Question 4

What is xerophthalmia?

Answer 4

Leads to blindness, conjunctivae become dry and develop oval/triangular spots (Bitot’s spots). Corneas become cloudy and soft.

Question 5

What are the diseases associated with Vitamin B1 deficiency? (x2)

Answer 5

Beriberi and Wernicke’s encephalopathy

Question 6

What is Beriberi?

Answer 6

Heart failure with general oedema (wet beriberi) or neuropathy (dry beriberi)

Question 7

What is the disease associated with B2 deficiency?

Answer 7

Angular stomatitis, aka cheilitis (fissuring of the mouth’s corners)

Question 8

What is the disease associated with B6 deficiency?

Answer 8

Polyneuropathy.

Question 9

What is the disease associated with Vitamin C deficiency?

Answer 9

Scurvy

Question 10

What are the signs and symptoms of scurvy? (x5)

Answer 10

(1) listlessness (no energy), anorexia, cachexia, (2) gingivitis, loose teeth, foul breath (halitosis), (3) bleeding from gums, nose, hair follicles, or into joints, bladder, gut, (4) muscle pain and weakness, (5) oedema

Question 11

How is scurvy investigated?

Answer 11

Serum ascorbic acid (Vitamin C) is low

Question 12

What are the diseases associated with Vitamin D deficiency? (x2)

Answer 12

Rickets in children and osteomalacia in adults

Question 13

What are the diseases associated with Vitamin E deficiency? (x2)

Answer 13

Haemolysis and neurological deficit.

Question 14

What is the disease associated with Vitamin K deficiency?

Answer 14

Bleeding disorders

Question 15

What ais the disease associated with nicotinamide (B3) deficiency?

Answer 15

Pellagra

Question 16

What is pellagra?

Answer 16

Classic triad of DDD: diarrhoea, dementia, dermatitis (Casal’s necklace) +/- neuropathy, depression, insomnia, tremor, rigidity, ataxia, fits.

Question 17

What is the association with pellagra? (x2)

Answer 17

Carcinoid syndrome and anti-TB drugs such as isoniazid

Question 18

How is pellagra treated?

Answer 18

Oral nicotinamide (called niacin) and electrolyte replacement from diarrhoea.

Question 19

What is Pabrinex?

Answer 19

IV replacement of water-soluble vitamins C (ascorbic acid), B1 (thiamine), B2 (riboflavin), B3 (nicotinamide) and B6 (pyridoxine).

Question 20

What is refeeding syndrome?

Answer 20

Life-threatening metabolic complication of refeeding after a prolonged period of starvation or deficiency in any vitamin. This is because as the body switches to protein and fat metabolism in the starved state, there is a drop in circulating insulin. The catabolic state also depletes intracellular stores of phosphate even though serum levels may remain normal. As such, when refeeding begins, the level of insulin rises in response to the carbohydrate load. One of the consequences of this is increased cellular uptake of phosphate. Refeeding syndrome is characterised by the subsequent hypophosphatemia which can manifest as: rhabdomyolysis, RBC and WCC dysfunction, respiratory insufficiency, arrythmias and seizures.

Question 21

How is refeeding syndrome prevented?

Answer 21

High dose Pabrinex at the start of re-feeding