Hypoglycemia Flashcards Preview

Endocrinology > Hypoglycemia > Flashcards

Flashcards in Hypoglycemia Deck (43):
1

When does hypoglycemia occur?

Glucose utilization exceeds production

2

What tissue is absolutely dependent on glucose? What does it use when glucose not available?

Brain needs glucose, but uses ketones in absence

3

What are main tissues of glucose use?

Brain, muscle, RBC/WBC, renal medulla

4

Sources of glucose (3)

Ingestion
Gluconeogenesis: long term
Glycogenolysis: exhausted 24-36 hr

5

Fasting hormonal response on glucose utilization: What are effects of insulin, glucagon, epinephrine, cortisol, growth hormone?

Insulin: Suppresses all glucose utilization
Glucagon: Glycogenolysis, gluconeogenesis
Epinephrine: Glycogenolysis, lipolysis, ketogenesis
Cortisol: gluconeogenesis
GH: lipolysis

6

What happens with decrease in insulin?

Increase in fatty acids and ketone generation

7

At what plasma glucose are symptoms noticeable? Is it above or below levels for hormonal secretion

50-55mg/dL
This is below levels for hormonal secretion

8

Whipple's Triad

Symptoms/signs compatible with hypoglycemia
Low plasma glucose
Resolution of symptoms/signs when plasma glucose restored to normal

9

Neurogenic symptoms of hypoglycemia: Adrenergic (3) and Cholinergic (3)

Result of sympathetic nervous discharge in response to hypoglycemia

Adrenergic: palpitations, tremor, anxiety
Cholinergic: sweating, hunger, paresthesis

10

Neuroglycopenic Symptoms (big list)

Result of failure of brain function
Confusion, dizziness, fatigue, inability to concentrate, blurred vision, headache, focal neurological signs, loss of consciousness, seizures, depressed respiration, death

11

Which symptoms come first?

Neurogenic precede neuroglycopenic symptoms

12

What is the impact of previous episodes of hypoglycemia? (2)

Attenuate adrenergic response
Hypoglycemia-associated autonomic failure

13

What are 3 broad categories of fasting hypoglycemia?

1. Insulin-mediated (too much insulin) (4)
2. Failure of counter-regulation (too little counter) (2)
3. Congenital error of metabolism (3)

14

What is most common cause (broad) of persistent hypoglycemia? Is the specific cause different for adults vs. children?

Most common cause is hyperinsulinemia
For adults most likely due to insulinoma
For children, most likely due to congenital hyperinsulinism

15

What are diagnostic criteria for hyperinsulinemic hypoglycemia? (5)

Hyperinsulinemia
High C-peptide
Hypofattyacidemia
Hypoketonemia
Glycemic response to glucagon

16

Are insulinomas big or small? Usually benign or malignant? Where are they located?

Typically small and benign.
Usually located in pancreas

17

What are ectopic locations for insulinomas? (5)

Duodenum, Meckel's diverticulum, bile duct, ovary, omentum

18

Biochemical profile of insulinomas (3)

Elevated insulin, proinsulin (25% of circulating insulin) and C-peptide

19

How are insulinomas treated?

Surgical resection

20

What congenital syndrome is associated with congenital hyperinsulinism?

Beck with Wiedemann syndrome

21

What is classic presentation of congenital hyperinsulinism? (3)

Severe neonatal hypoglycemia
Large birth weight
High glucose requirements

22

Diffuse vs. Focal hyperinsulinism Treatment

Focal: remove affected area
Diffuse: need to use therapy

23

Pharmacological Treatment for hyperinsulinemic hypoglycemia: Diazoxide--MOA and AE

Activates ATP-dependent K channel

Side effects: fluid retention, hypertrichosis

24

Pharmacological treatment for hyperinsulinemic hypoglycemia: Octreotide--MOA and AE

Activates ATP dependent K channel, affects intracellular translocation of Ca, direct inhibition of insulin secretion

Tachyphylaxis, suppression of GH/TSH/ACTH, GI side effects, necrotizing enterocolitis

25

Categories of Autoimmune hypoglycemia

Bind to insulin receptor: agonists (hypoglycemia) or antagonists (hyperglycemia)

Insulin antibodies (hirata's disease): fasting hypoglycemia

26

GH/Cortisol Deficiency: Clues (3)

Midline defect, microphallus, cholestatic liver disease

27

GH/Cortisol deficiency: treatment (2)

Shorten fasting, hormone replacement

28

Critical samples in GH/cortisol deficiency:

Ketone pattern

29

G6Pase deficiency: Clinical (2)

Impaired gluconeogenesis/glycogenolysis

Failure to thrive, hepatomegaly

30

G6Pase deficiency: Labs (3) and test (1)

Hyperlacticacidemia, hyptertriglyceridemia, hyperuricemia

Lack of glycemic response to fed glucagon stimulation test

31

G6Pase deficiency: Treatment (4)

Frequent carb-rich meals
Intragastric dextrose
Uncooked cornstarch
No lactose/fructose

32

G6Pase deficiency: Types

Glycogen storage disease 1a
Glycogen storage 1b (10%): added neutropenia

33

F1,6BP deficiency: Clinical signs and trigger

Attacks of acidemia, hyperlacticacidemia, hyperuricemia

Triggered by fasting/fructose

34

F1,6BP deficiency: Rx (2)

Limit fasting to less than 8-12 hours
No fructose/sucrose

35

Glycogen Debrancher Deficiency (GSD type 3): Clinical signs (3)

Failure to thrive, hepatomegaly, muscle weakness

36

Glycogen Debrancher Deficiency (GSD type 3): labs

Impaired glycogenolysis: hyperketonemia

37

Glycogen Debrancher Deficiency (GSD type 3): Rx (3)

Frequent low carb feeds
Intragastric dextrose
Uncooked cornstarch

38

Late symptoms of Glycogen Debrancher Deficiency (GSD type 3) (2)

Cardiomyopathy
Myopathy

39

Medium Chain Acyl-CoA Dehydrogenase Deficiency--FAO defect: Signs (2)

Hypoketotic hypoglycemia
Mimics Reye's syndrome

40

Medium Chain Acyl-CoA Dehydrogenase Deficiency--FAO defect: Rx (1)

Limit fasting to less than 12 hours

41

Hypoglycemia due to drugs (4)

Sulfonylureas
Salicylate OD
Beta-adrenergic blocking agents (no adrenergic warning signs, HHS pattern)
Pentamidine for pneumocystis

42

What substance can stimulate hypoglycemia in fasting state? How does it do this?

Alcohol; by using NDH

43

DDX of Hypoglycemia based on critical sample

See chart! Know chart!