Download Hypoglycemia

Hypoglycemia
Paolo Aquino
29 January 2003
Overview of hypoglycemia
 What
is it?
 Why do we care about it?
 What causes it?
 How do we diagnose it?
 What do we do about it?
 How do we prevent it?
What is it?
Strictly, hypoglycemia refers to a low level
of serum glucose
 It occurs when a mismatch of endogenous
glucose need with exogenous and
endogenous glucose availability derails the
metabolic engine of normal glucose
homeostasis
 Often defined as a plasma glucose level <
2.5-2.8 mmol/L (< 45-50 mg/dL)

Why do we care about it?
Because
hypoglycemia
can kill
Why do we care about it?
 Physiology
– Glucose is an obligate metabolic fuel for
the brain under physiologic conditions,
while other organs can use other forms
of fuel (i.e. fatty acids)
– The brain can not synthesize its own
glucose; it requires a continuous supply
via arterial blood
Why do we care about it?
 Physiology
– As the plasma glucose concentration
falls below the physiologic range, bloodto-brain glucose transport becomes
insufficient for adequate brain energy
metabolism and functioning
Why do we care about it?
 Maintenance
of glucose homeostasis
– Narrow plasma glucose range is
normally maintained despite fluctuations
in food intake and activity levels
– Maintenance through diet, glycogen
breakdown (liver) and gluconeogenesis
(liver and kidney)
Glucose metabolism
Glucose metabolism
 Glycogen
stores can last 8-12 hours
 Precursors for gluconeogenesis
coordinated amongst liver, muscle
and adipose tissue
– Muscle: lactate, pyruvate, amino acids
– Adipose: glycerol, fatty acids
Hormonal control
 Insulin-
inhibits glycogenolysis and
gluconeogenesisdecreased serum
glucose
 Glucagon- promotes glycogenolysis
and gluconeogenesis
 Epinephrine- limits utilization of
glucose by insulin-sensistive tissues
 Growth hormone and cortisol have a
role during prolonged hypoglycemia
What causes it?
 Two
major etiological classes
– Increased insulin levels
 Over-medicating
 Insulinoma
 Sepsis
– Underproduction of glucose
 Medications-
alcohol, salicylates, b-blockers
 Adrenal insufficiency
 Liver disease
 Malnutrition, dehydration
Hypoglycemia in diabetes
Whipple’s Triad
 Symptoms
of hypoglycemia
 Low plasma glucose levels
 Resolution of symptoms with
administration of glucose
Symptoms
 Adrenergic:
diaphoresis,
tachycardia, anxiety, hunger
 Neuroglycopenic:
dizziness,
confusion, slurred speech, seizure
Diagnosis
 History
– Drug use, infection, illness (hepatic,
renal, cardiac), surgeries
 Laboratory
tests- serum glucose,
CBC, lytes, BUN/Cr, UA
 Other tests: ECG, CXR
Diagnosis
 Differential
– Neurologic: CVA/TIA, seizure disorder
– Drug/alcohol intoxication
– Psychosis, depression
Treatment

Glucose
– Oral glucose
– IV dextrose: 5-20% solutions, 50% ampules
– IM glucagon
Monitor glucose q 2-4 hours
 If adrenal insufficiency, administer 100 mg
hydrocortisone & 1 mg glucagon
 If resistant hypoglycemia secondary to
sulfonylureas, administer diazoxide 300
mg over 30 minutes IV q 4 hours PRN

Prevention
 Treatment
of underlying problem
– Eliminate/reduce offending drug
– Resection of insulinoma
– Treat infection
– Frequent feedings, avoidance of fasting