Glucose Homeostatis In The Neonate

Question 1

Risk factors for hypoglycaemia

Answer 1

Prematurity
Small for gestational age
Maternal diabetes
Large for gestational age
Perinatal asphyxia/ resuscitation
Use of beta blockers such a labetalol
Infection
Clinical signs
Low temperature (unable to maintain)
Reluctant feeder

Question 2

Signs of hypoglycaemia

Answer 2

Reluctant feeding
Inadequate thermoregulation
Lethargy
jittery baby

Question 3

What increases towards term and what remains low?

Answer 3

Fetal insulin levels increase towards term
glucagon levels remain low
Leads to glycogen storage becoming sufficient in 3rd trimester
(Stored in liver heart and skeletal muscles)
In order to support neonatal transition to intrauterine life.

Question 4

When may stores of glycogen be inadequate?

Answer 4

pre term infant - may not have an appropriate time to store glycogen during the 3rd trimester
Pre natal stress in fetus - as going to be using up stores of glycogen

Question 5

When does metabolic demands of the fetus increase?

Answer 5

At birth
The infant must supply its own glucose needs of approx 5-8mg/kg/min

Question 6

What are the two sources of glucose for the neonate?

Answer 6

Exogenous sources - (human milk)
Endogenous glucose production through processes of:
Glycogenolysis - breakdown of stored glycogen into glucose.
Gluconeogenesis - formation of glucose from non carbohydrate sources such as glycerol and lactate.
Ketogenesis - production of ketone bodies by the liver as an alternative energy supply for the body by breaking down fatty acids.

Question 7

What happens to insulin levels at birth?

Answer 7

Plasma insulin levels fall to slow down the storage of glucose

Question 8

What happens to plasma glucose levels in the first 2-3 hours of life?

Answer 8

Normal plasma glucose levels drop
Why we should not be measuring blood glucose immediately after birth

Question 9

How do infants adapt to extrauterine life?

Answer 9

Will mobilise their stored glucose and fatty acids until feeding is more established

Question 10

What is gylcogenolysis?

Answer 10

Using glycogen stores to release glucose

Question 11

What percent of hepatic glycogen stores are used within the first 24 hours of extrauterine life?

Answer 11

90%

Question 12

What percent of muscle glycogen stores are used in the 1st 24 hours of life?

Answer 12

50-80%

Question 13

What is gluconeogenesis?

Answer 13

Glucose formation from smaller molecules (lactate’s and pyruvates)

Question 14

What is gluconeogensis regulated by?

Answer 14

Changes in serum insulin glucose ratio
Catecholamine release (stress hormones from fetus during labour) - sources of energy not so readily available for the neonate after birth

Question 15

What is ketogenesis?

Answer 15

Production of ketone bodies by the liver as an alternative energy source

Question 16

Why are ketones considered bad in the neonate?

Answer 16

Can be suggestive of lack of other fuel sources such as glucose and gluconeogenesis

Question 17

What does feeding colostrum from the breast allow?

Answer 17

The neonate to meet their nutritional needs and maintain their blood glucose

Question 18

What happens when there is a low plasma glucose level?

Answer 18

Serum glucagon levels rise
Converts glycogen stores into glucose
Glycogen stores decrease rapidly over the first 24 hours of life.

Question 19

What are healthy term neonates born with?

Answer 19

Glycogen and fat stores to meet their nutritional needs

Question 20

What are considerations for the pre term neonate?

Answer 20

Thermoregulation issues - use energy more rapidly to keep themselves warm
3rd trimester glycogen storage disrupted - limited glycogen and fat stores
Inability to generate new glucose using gluconeogenesis
May struggle with feeding
Increased metabolic demand due to relatively larger brain size