191b - Starvation and Metabolic Adaptation Flashcards
What is the difference in the cause of Marasmus vs. Kwashiorkor?
- Marasmus = not enough calories
- -> Very low body weight, wasted appearance
- Kwashiorkor = not enough protein
- -> Low or normal body weight, edema, distended abdomen
What is the difference between total parenteral nutrition and peripheral parenteral nurition?
- Total parenteral nutrition
- High osmolality => must be administered into vena cava
- Can meet energy and protein needs
- Peripheral parenteral nutrition
- Lower osmolality => can be infused in a peripheral vein
- Usually cannot completely meet energy/protein needs
Describe the differences in the presentation of Marasmus vs. Kwashiorkor
-
Marasmus (calorie deficiency)
- Very low body weight
- Wasted appearance (loss of fat and muscle)
- Normal liver function
- Dry, inelastic skin
-
Kwashiorkor (protein deficiency)
- Low or normal body weight
- Edema -> may appear normal weight
- Distended abdomen
- Dysfunctional liver; marked hypoalbuminemia (-> edema)
- Flaky paint rash, depigmentation of hair
Which tissues can use ketone bodies in late starvation? (2)
Brain
Muscle
What behavior changes occur in normal volunteers during starvation? (5) (Keys et al)
- Preoccupation with food
- Hoarding and stealing food
- Bing eating if opportunity
- Abnormal taste preferences
- Depression, apathy, irritability, other personality changes
- Cannot psychologically rehabilitate until nutritionally rehabilitated
Which tissues use FFAs in late starvation? (2)
Muscle
Liver
How does muscle metabolism change during starvation?
Muscles become more efficient
=> Fewer calories burned, conserves energy
Major burn
- Protein loss through open wounds
2-3 months
(but varies with starting adiposity)
Which tissues use glucose in late starvation? (3)
Brain
RBCs
Renal medulla
What is metabolic adaptation (after weight loss)?
Changes in metabolism/hormones that occur after weight loss; evolutionarily, they are aimed at preventing death from starvation
In short, BMR decreases
- Decreased:
- Leptin
- Energy expenditure T3/T4
- Increased
- Ghrelin
- Muscular efficiency (-> decreased calorie burn)
How can refeeding syndrome be prevented?
- Replete electrolytes before calories
- Go slowly with calories
- Replete thiamine
- Cofactor for pyruvate dehydrogenase - needed to metabolize glucose/carbohydrates
Monitor and continue repleting as necessary!
How long does metabolic adaptation to weight loss persist?
Forever (many years)
- This means that even YEARS after a pt has lost weight, their body will be trying to conserve energy because it thinks its starving
- BMR continues to slow
Describe the pathogenesis of refeeding syndrome
Glucose intake
- Electrolyte shift into cells
- Low blood electrolytes
- Arrhythmia, decreased contractility
Simultaneous fluid -> exacerbation of heart failure
Prevent by repleting electrolytes prior to nutrition, go slow with nutrition
How many grams of dietary carbohydrates/day will suppress ketosis and glucogneogenesis?
100 g
C
- This is Kwashiorkor (caused by marked protein deficiency)
- Very hypoalbuminemic
- Skin and hair changes
- Distended abnomen
- Fatty/dysfunctional liver
