Hypoglycemia Flashcards Preview

Medical Biochemistry > Hypoglycemia > Flashcards

Flashcards in Hypoglycemia Deck (37)
Loading flashcards...
1
Q

Hypoglycemia is characterized by what Bl glucose levels?

A

Less than 55 or even 40mg/dl (2.2mM while normal is 5mM)

2
Q

What can cause Adrenergic symptoms?

A

When the bl glucose levels falls quickly and when epinephrine release is stimulated.

3
Q

What can cause Neuroglycopenia symptoms?

A

Due to gradual decline in bl glucose depriving the brain of glucose. Epinephrine is not released.

4
Q

Differentiate between the symptoms of Adrenergic and Neuroglycopenia?

A

Adrenergic symptoms: anxiety, palpitation, tremor, sweating

Neuroglycopenia: symptoms: headache, confusion, slurred speech, coma, death (more serious bc the brain has no glucose)

5
Q

Transient hypoglycemia can lead to what?

A

cerebral dysfunction

6
Q

Why are injections of glucagon or epinephrine used to treat hypoglycemia?

A

To help release glucose from liver into bl via glycogen degradation.

7
Q

How does the pituitary gland / ACTH counteract insulin and normalize bl glucose levels?

A

by stimulating adrenal cortex to release cortisol to stimulate gluconeogenesis (not glycogenolysis)

Stimulates adrenal medulla to release epinephrine which will stimulate glycogenoglysis but not gluconeogenesis.

8
Q

How does the autonomic nervous system counteract insulin and normalize bl glucose levels?

A

It stimulates the release of norepinephrine to stimulate glycogenolysis (doesn’t affect gluconeogenesis)

9
Q

Prolonged hypoglycemia leads to what?

A

coma and even death

10
Q

How does the low bl glucose acting on alpha cells of pancreas normalize bl glucose levels?

A

Stimulates release of glucogon which will will stimulate both glycogen breakdown and gluconeogenesis.

11
Q

What occurs in response to low bl glucose levels?

A

Insulin production decreases, epinephrine / glucogon increases, Growth hormone increases, adrenergic symptoms begins (anxiety, palpitation, tremor and sweating), then neuroglycopenia symptoms begins (headaches, confusion, slurred speech, seizures, coma) begins (in this order)

12
Q

What is postprandial hypoglycemia and how can it be prevented?

A

exaggerated insulin release after meal; transient hypoglycemia. Can be prevented by having small meals often

13
Q

What can cause insulin induced hypoglycemia?

A

pt accidentally injects too much insulin and insulinoma

14
Q

What is insulinoma and what is it characterized by?

A

Tumor of pancreatic cells resulting in severe hypoglycemia; characterized by high levels of insulin, C-peptide and proinsulin

15
Q

What are indicators of increased endogenous insulin production?

A

high levels of insulin, C-peptide and proinsulin

16
Q

What is the treatment for mild and severe hypoglycemia?

A

Mild: oral intake of carbohydrate like orange juice; severe: glucagon administration

17
Q

What can result in fasting hypoglycemia?

A

serious medical problems/ genetic defects:

1) glycogen storage diseases
2) abnormal frucotose/ galactose metabolism
3) abnormal carnitine shuttle or abnormal metabolism of FA degradation

18
Q

What glycogen storage disease results in severe fasting hypoglycemia?

A

Von Gierke’s disease

19
Q

What is deficient in Von Gierke’s disease?

A

glucose 6 phosphatase which will inhibit both glycogen degradation of liver and gluconeogenesis

20
Q

What are some symptoms that characterize Von Gierke’s disease?

A

Severe hypoglycemia, high levels of glycogen in liver and kidney, lactic acidemia and gout

21
Q

What glucogen storage disease result in milder hypoglycemia?

A

Hers disease and Cori disease

22
Q

What is deficient in Cori disease?

A

debranching enzyme, limit dextrinosis.

23
Q

What is deficient in Hers disease?

A

liver phosphorylase

24
Q

Pts with Hereditary fructose intolerance have deficiency of what enzyme? what will accumulate?

A

aldolase B w/ accumulation of Fructose 1-P in liver

25
Q

How do u treat the severe fasting hypoglycemia in Hereditary fructose intolerance?

A

By removing sucrose, fructose, and sorbitol from diet bc sorbitol can form fructose via sorbitol DH resulting in increase of F-1P

26
Q

What is deficient in classical galactosemia?

A

galactose 1P uridytransferase (GALT)

27
Q

What is found in pts with classical galactosemia?

A

fasting hypoglycemia, accumulation of galactose 1P and galactitol in liver, nerve, lens and kidney. Pts will have liver damage, severe mental retardation and cataracts.

28
Q

Treatment for hypoglycemia in classical galactosemia?

A

Remove lactose and galactose from diet.

29
Q

What accumulates in MCAD deficiency?

A

medium chain fatty acyl carnitines and dicarboxylic acids (in Bl/ urine)

30
Q

Why are hereditary defects of B-oxidation (especially MCAD) life threatening?

A

Results in fasting hypoglycemia. MCAD (medium chain fatty acyl CoA deydrogenase) necessary to provide E for gluconeogenesis during fasting.

31
Q

What can cause carnitine shuttle related fasting hypoglycemia?

A

Carnitine def or def of CPT1 in liver. (Severe form leads to early death in childhood)

32
Q

What type of pts are most vulnerable to fasting hypoglycemia induced by high ethanol levels?

A

undernourished or dehydrated pts

33
Q

Why does high alcohol consumption result in fasting hypoglycemia?

A

High alcohol consumption results in high NADH/ NAD ratio in cytosol which will decrease usable precursors for gluconeogenesis

34
Q

What characterizes exogenous administration of insulin?

A

high levels of insulin with low levels of C-peptide and proinsulin.

35
Q

What can cause Factitious hypoglycemia?

A

Injection of insulin (exogenous administration) or intake of Sulfonylurea in the absence of diabetes (endogenous administration)

36
Q

How does sulonylurea cause hypoglycemia in pts w/out DM?

A

Drug used for DM type II pts that stimulates pancreas to secrete insulin

37
Q

What are facticious disorders and what is the most severe form?

A

mental / personality disorders; most severe: Munchhausen syndrome: come up w/ different diseases (stimulate diseases)