What are the symptoms of hypoglycemia and hyperglycemia?

May be quite varied! Hypoglycemia: shakiness, sweating, hunger, palpitations. If severe: confusion, lethargy, seizure, or coma could occur. Hyperglycemia: no symptoms if mild (that's what's so dangerous over long periods of time). If severe: frequent urination, ravenous thirst. If not addressed over long periods of time, damage to kidneys, nerves, eyes, and blood vessels can result.