Hypoglycemia (aka low blood sugar) is when blood sugar decreases to below normal.

Sx typically come on quickly, including:

• Feeling of hunger
• Cold sweatiness
• Shakiness, trembling, or jiteriness
• Weakness
• Pounding heart
• Pallor
• Neurological Sx:
  • Clumsiness
  • Trouble talking
  • Difficulty concentrating
  • Blurred/double vision
  • Difficulty hearing
  • Slurred speech
  • Confusion
  • Diziness, unsteady gait
  • Irritability, inconsolability
  • Loss of consciousness
  • Seizure
  • Death

• Drugs, used to Tx diabetes mellitus, e.g. insulin, sulfonylureas, biguanides
• Diabetics, who have eaten less than usual, exercised more than usual, or drunk alcohol
• Kidney failure
• Certain tumors
• Liver disease
• Hypothyroidism
• Starvation
• Inborn error of metabolism
• Sepsis (severe infection)
• Reactive hypoglycemia
• Drugs, including alcohol
• Babies who are otherwise healthy, who haven't eaten for a few hours

The glucose level defining hypoglycemia is variable, including:

• In diabetics, <3.9mmol/L
• In non-diabetic adults:
  • Sx related to low BSL, low BSL at the time of Sx, and improvement when BSL is restored to normal confirm the Dx
  • <2.8mmol/L after not eating, or following exercise
• In newborns, <2.2mmol/L, or <3.3mmol/L if Sx are present

• Insulin
• C peptide levels

• Prevention, in patients with diabetes:
  • Matching the foods eaten, with the amount of exercise, and drugs used
  • When patients feel their BSL is low, testing with a glucose monitor is recommended. Some patients have few initial Sx of low BSL and frequent routine testing in this group is recommended
• Some forms of hypoglycemia (e.g. in diabetes) involves immediately raising BSL's to normal through ingestion of carbohydrates, but this is not optimal for reactive ypoglycemia, where rapid carbohydrate ingestion can cause a further hypoglycemic episode. It includes:
  • Eating foods high in simple sugars, containing 15g of carbohydrate, followed by a 15 minute wait, repeating if BSL's remain low, called the rule of 15. This is contained in 100-120mL of orange/apple/grape juice, although fruit juices contain higher proportion of fructose whic his more slowly metabolized than pure dextrose. 120-15mL non-diet soft drink can be used, or 1 slice of bread, 4 crackers, or 1 serving of most starchy foods
  • Bolus IV dextrose, 2mL/kg, 10% dextrose in infants, 25% in children, and 50% in adults), if the patient can't (due to combativeness) or shouldn't (due to seizures or unconsciousness) be given PO
  • IV maintenance fluids containing glucose
  • Injection of glucagon, if the patient is not able to take food by mouth
• Tx of underlying problem, if it is unrelated to diabetes
• Well and healthy diet

• After ingestion of carbohydrates, Sx should improve within 5 minutes, although full recovery may take 10-20 mins
• Overfeeding doesn't speed recovery, and if the patient has diabetes it'll simply produce hyperglycemia

• Diabetic hypoglycemia
• Hyperglycemia (high blood sugar, antonym)
• Idiopathic postprandial syndrome (similar Sx, but occurs following eating but with normal BSL's)