Hyperglycemia
Definition -causes
Definition
Hyperglycemia means increased blood glucose concentration
Increased blood glucose concentration results from either imbalance between hepatic input of glucose and peripheral uptake or disturbance of endocrine regulatory influence upon this process
So that hyperglycemia may resulted from :
a- Normal hepatic output of glucose with subnormal
rate of peripheral removal .
b - An increase in hepatic production and releaseof
glucose accompanied with normal removal
rate of peripheral tissues
c- A combination of these factors
Causes
Causes of hyperglycemia can be summarized as follow :
1 - Diabetes mellitus where fasting blood glucose
over 200 mg/dl due to lack of insulin or its response
2 - Postprandial for up to 4 hours after meals
3- Epinephrine release due to excitement ,pain or stress as it mobilize stored glycogen in the liver and usually transient .
4 - Stress with increase of glucocorticoides
and catecholamines , they stimulate glycogenlysis and glyconeogenesis it usually returns to normal within 6 - 24 hours .
5 - Pancreatitis , often associated with disturbed carbohydrate utilization and when advanced it can cause diabetes mellitus .
6 - Cushing's disease or administrations of glucocorticoides . it increase hepatic gluconeogenesis .
7 - Convulsions of epilepsy , tetany , and intracarnial trauma due to a combination of anoxia and epinephrine secretion ( liver glycogen is unstable in case of anoxia )
8 - Thyrotoxicosis
9 - Administration of drugs :
a- After general anesthesia .
b- Morphine .
c - strychnine .
d- Glucose .
e - Thyroid preparation .