L29 Hypoglycemia Flashcards
What is the definition of adult hypoglycemia?
Plasma glucose <2.5 mmol/L by laboratory method
One of the causes of hypoglycemia is excessive glucose utilization. List 4 sub-causes.
- Insulin administration
- Oral hypoglycemic
- Insulinoma
- Extra-pancreatic tumors
One of the causes of hypoglycemia diminished glucose production. List 4 sub-causes.
Briefly describe each cause.
- Primary/secondary adrenal insufficiency (MC)
- GH deficiency
- depleted cortisol increases insulin sensitivity - Liver disease
- reduced glycogen reserve in cirrhosis - Renal disease
- multifactorial
- uremia inhibits liver gluconeogenesis and causes poor appetitie, reduced insulin clearance - Autoimmune cause
- agonist auto Ab to the insulin receptor
- agonist auto Ab to beta cells
Insulin administration overdose
What to expect to see in serum insulin and C-peptide? (2)
Serum insulin increased
C-peptide reduced
(exogenous insulin suppresses endogenous insulin secretion. )
List examples of hypoglycemic drugs. (2)
Meglitinides, glyburide, DPP-4 inhibitors
TZD (thiazolidinedione) in combination with metformin
What to expect to see in serum insulin and C peptide in hypoglycemia caused by oral hypoglycemics? (2)
How to differentiate this cause from insulinoma? (1)
Serum insulin increased
C peptide increased
Urine drug screen
What is Whipple’s triad in hypoglycemia?
- Low plasma glucose concentration measure with a laboratory method
- Symptoms consistent with hypogly
- Relief of those symptoms after plasma glucose is raised
List some symptoms of hypogly.
Fall in blood glucose stimulates the release of catecholamines which results in symptoms such as sweating, tremor, anxiety, hungriness.
What is neuroglycopenia? List some symptoms
Poor concentration, delirium, convulsions, slurred speech
due to decreased CSF glucose level
Insulinoma:
serum insulin and C-peptide? (2)
High serum insulin
High C-peptide even during fasting (at all times)
Pathophysiology of an insulinoma?
Secretion of insulin and C-peptide ratio?
Pancreatic islet adenoma that produces insulin and C-peptide in equimolar ratio
may have family history of MEN (multiple endocrine neoplasia)
Examples of extra-pancreatic tumors?
- Retroperitoneal fibrosarcoma
2. Hepatoma
Pathophysiology of extra-pancreatic tumors?
- Increase “big” IGF-2 or similar molecule (insulin-like growth factor)
- Suppression of insulin and GH
- Reduced IGFBP3 and IGF-1, increased free IGF-2
- Reduced hepatic glucose production + increase glucose uptake by peripheral tissues
How to diagnose extra-pancreatic tumors causing hypoglycemia? (4)
- low serum Insulin
- low C-peptide
- high IGF-2
- low IGFBP3
How to diagnose adrenal insufficiency cause of hypoglycemia?
Short synacthen test;
Glucagon stimulation test
(glucagon should come out and help normally!)