Lecture 3: Protein Energy Malnutrition

Question 1

Hoe fast does PEM form?

Answer 1

Gradually in weeks/months

• allows a series of metabolic and behavioral adjustments to occur as the body gets smaller

Question 2

PEM Adaptations

Answer 2

• Low insulin levels (affects thyroxine, lowers heat production + oxygen consumption)
• Non-vital hormonal secretion decrease
• Red blood cells production decrease (decrease O2 demands <- lower #lean body mass)
• Heart muscle reduces in size is parallel with loss of lean body
  mass
  (Combination of less cardiac proteins/cells being made +
  protein being broken down shrinking of heart muscle (i.e.
  cardiac atrophy).

Question 3

PEM Adaptations: Cardiovascular and kidney function changes

Answer 3

◦ Cardiac output, heart rate and blood
pressure decrease

◦ Central circulation takes precedence over peripheral circulation

◦ Allows heart to function in setting of
reduced oxygen consumption (not
circulatory failure)

Question 4

PEM Adaptations: Cardiac

Answer 4

Is reduced in proportion to the smaller size of the ventricles
- w/ reduction in cardiac output (CO) and stroke volume (SV) occurring at the same time

Cardiovascular reflexes are altered
- Can lead to postural hypotension and
decreased venous return
- In severe PEM can get peripheral
circulation failure comparable to
hypovolemic shock.

Question 5

Formula for cardiac output

Answer 5

CO = (SV)(HR)

CO: Toal amount of blood pumped through body
SV: amount pumped from left ventricle during a contraction per min

Question 6

PEM Adaptations: Kidney function

Answer 6

Decreased renal plasma flow and glomerular filtration rate are due to decreased cardiac output
- Water clearance and ability to concentrate and acidify urine are not impaired

Kidneys are slowed down, BUT are
still able to remove toxins from your
body and filter water.

Question 7

PEM Adaptations: Respiratory
System

Answer 7

Expiratory and inspiratory muscles
are catabolized

Reduction in diaphragmatic mass is
proportional to the loss of body weight

Decreased respiratory muscle strength, maximum voluntary ventilation, vital capacity and maximum inspiratory
pressure
- Simple terms: Not at much
muscle strength, so less ability to take
deep breathes, as many breaths and as often, as well as the ability to breathe out as much

Question 8

PEM: Respiratory Adjustments

Answer 8

Lowered basal metabolic rate leads to a decreased ventilatory response to a lack of oxygen in the blood and an increase in carbon dioxide

Deterioration of function and emphysema like changes have been seen (increased, shorter, shallow breaths, can’t catch your breath)

Decreased surfactant synthesis, storage and secretion

Also see increase in infections due to
decrease in immune function, reduced
ability to clear secretions, and
impaired muscle function

Question 9

PEM: Immune System Changes

Answer 9

• Affects the T cells
• Alters monokine metabolism (chemical signals activating immune system)
• Esp. decreased activity of IL-1 (which leads to T-cell production) (may lead to low proliferation of T cells)