0507 - Nutrient Malabsorption and Deficiency

Question 1

In a starvation state, in what order are body energy stores burned?

Answer 1

First burn glycogen (70-150g in liver, 300-500 in muscle), then fat (average person has 10kg), then protein.

Question 2

What are the two forms of macronutrient starvation?

Answer 2

Marasmus - Global deficiency
Kwashiorkor - Protein deficiency
Distinction is clear in children, not clear in adults.

Question 3

What are the metabolic consequences of starvation?

Answer 3

Muscle function first affected.
Susceptibility to infection
Tissue atrophy - less fat (pressure sores, poor absorption)
Poor tolerance to major surgery

Question 4

What happens to electrolytes in malnutrition and refeeding?

Answer 4

Malnutrition - only K drops.

Re-feeding - Mg, K, and P serum levels fall.

Question 5

Briefly outline Thiamin (B1) role and deficiency

Answer 5

Thiamin required to convert pyruvate to Acetyl CoA. Also required for pentose-phosphate shunt to produce NADPH and ribose.
Deficiency impairs these processes. Leads to Beriberi, Wernicke’s encephalopathy, psychiatric symptoms).
If suspect thiamin deficiency, NEVER give glucose without giving thiamin.

Question 6

Outline Folate and B12 deficiencies

Answer 6

Folate doesn’t have neurological aspects. B12 does. Both give you a macrocytic anaemia.
Deficiencies rare, malabsorptions fairly common.
ALWAYS give B12 before giving them folate.

Question 7

Outline Vitamin C (Ascorbic Acid) deficiency

Answer 7

Main manifestation is inadequate collagen synthesis - bleeding gums, perifollicular haemmorhage, anaemia, general lethargy.

Question 8

What are the consequences of Vitamin A deficiency

Answer 8

Leads to night blindness, susceptibility to infection, and premature death.

Question 9

What are the complications of Iron deficiency

Answer 9

Presents with fatigue, and anaemia.
Also possible - angular stomatitis, glossitis, and oesophageal web.
Blood film shows microcytic, hypochromic anaemia.

Question 10

How does Re-feeding syndrome present?

Answer 10

Extracellular hypophosphatemia, hypokalemia, and hypomagnesaemia. Also get acute thiamin deficiency and peripheral oedema.
Gives them cardiac arrhythmia.

Question 11

Key points

Answer 11

2 forms of macronutrient malnutrition - Kwashikor and Marasmus.
Important nutrient deficiencies are Iron, calcium, thiamin, ascorbic acid, folate, and B12
First thing that deteriorates on fasting is muscle function.
Never give glucose without thiamin
Never give folate to a patient who may have B12 deficiency. Supplement B12 first.