Metabol 3) Response to sepsis vs starvation

Question 1

What are the 2 basic differences between simple starvation and catabolic weight loss?

Answer 1

Simple starvation has metabolic adaption and lean tissue is conserved.
Catabolic weight loss has no adaption and lean tissue breakdown continues despite nutrient intake

Question 2

What is the difference between basal metabolic rate in simple starvation vs starvation superimposed onto injury?

Answer 2

Decreased in both

Question 3

What is the difference between glucose levels in simple starvation vs starvation superimposed onto injury?

Answer 3

Simple starvation: low

Starvation superimposed onto injury: high

Question 4

What is the difference between glucose utilisation in simple starvation vs starvation superimposed onto injury?

Answer 4

Simple starvation: limited glucose use

Starvation superimposed onto injury: increased glucose use

Question 5

What is the difference between gluconeogenesis in simple starvation vs starvation superimposed onto injury

Answer 5

Simple starvation: increased initially, decreased after 5-7 days
Starvation superimposed onto injury: increased

Question 6

What is the difference between protein catabolism in simple starvation vs starvation superimposed onto injury?

Answer 6

Simple starvation: low

Starvation superimposed onto injury: high

Question 7

What is the difference between fat catabolism in simple starvation vs starvation superimposed onto injury?

Answer 7

Simple starvation: high

Starvation superimposed onto injury: low / none

Question 8

What is the difference between ketone utilisation in simple starvation vs starvation superimposed onto injury?

Answer 8

Simple starvation: increased

Starvation superimposed onto injury: decreased

Question 9

What is the difference between ketosis in simple starvation vs starvation superimposed onto injury?

Answer 9

Simple starvation: present

Starvation superimposed onto injury: absent

Question 10

What is anorexia nervosa?

Answer 10

Severe restriction of nutritional intake causing severe nutritional deficiency

Question 11

Describe the consequences of low glucose caused by anorexia nervosa

Answer 11

Low glucose causes declines in insulin and increased glucagon release resulting in degradation of glycogen, fat stores and protein.
Brain adapts to use ketones

Question 12

Describe what happens to the fat tissue in anorexia nervosa

Answer 12

High glucagon activates hormone-sensitive lipase

Breakdown of TG to FFA

Question 13

What can cause ketoacidosis?

Answer 13

Diabetes ketosis
Fasting ketosis
Alcoholic ketoacidosis

Question 14

Describe alcoholic ketoacidosis

Answer 14

Characterised by hyperketonaemia and metabolic acidosis without significant hyperglycaemia.
Ethanol is metabolised to acetic acid (ketone)

Question 15

Describe the mechanism of ketosis

Answer 15

Liver produces ketones which is stimulated by low insulin and high glucagon.
Activation of lipase.
Fatty acids transported to liver, enter mitochondria and are oxidised to acetyl CoA.
Enter Krebs cycle to generate ATP or generates ketones

Question 16

What would the level of ketones be in mild ketosis after a 12 hour fast?

Answer 16

1mmol/L

Question 17

What would the level of ketones be after fasting for 20 days?

Answer 17

8-10mmol/L

Question 18

What 3 stabilisation methods occur in ketosis?

Answer 18

Stimulation of insulin release despite low glucose
Increased sensitivity of adipose tissue to insulin inhibitory effect on fatty acid release
Direct inhibition of lipolysis by ketones

Question 19

What are ketones?

Answer 19

A water-soluble, fat-derived fuel that is used when glucose is low.

Question 20

What tests should be done when considering sepsis?

Answer 20

Blood gas
Lactate
Glucose
Blood culture
FBC
CRP
Na+
K+
Cl-
HCO3-
eGFR
AKI staging
Phosphate
Calcium
Albumin
Magnesium
Coagulation
LFT

Question 21

What are some severe consequences of lactic acid production?

Answer 21

Hypovolaemia
Cardiac failure
Sepsis
Cardiopulmonary arrest

Question 22

Describe the hyper-metabolic response to injury

Answer 22

Increased BP and HR
Peripheral insulin resistance
Increased protein and lipid catabolism
Increased resting energy expenditure
Increased body temperature
Total body protein loss
Muscle wasting
Acute-phase protein response

Question 23

What are the causes of hyperglycaemia in critical illness?

Answer 23

Stress mediators oppose anabolic actions of insulin
Enhanced adipose tissue lipolysis
Enhanced skeletal muscle proteolysis
High catecholamines and cortisol

Question 24

Why does lean muscle protein breakdown occur in illness?

Answer 24

Pro-Inflammatory cytokines such as TNF

Reduced ability to use lipids as energy

Question 25

What is the consequence of a 10% loss in lean body mass?

Answer 25

Increased infection
Delayed wound healing
Muscle weakness
Prolonged mechanical ventilatory utilisation
Inhibits cough reflex
Delays mobilisation

Question 26

Describe some endocrine complications of starvation

Answer 26

Hypothalamic-pituitary abnormalities
Hypogonadotropic, hypogonadism
Low GnRH, LH, FSH, oestradiol
Amenorrhoea, infertility
Thyroid problems