Hypoglycemia

A blood glucose of 68 mg/dL in a conscious patient and a glucose of 68 mg/dL in an unconscious patient demand two completely different nursing responses — choosing wrong can be fatal.

Hypoglycemia is defined as blood glucose below 70 mg/dL. It results from too much insulin relative to available glucose — whether from exogenous insulin, oral hypoglycemics (especially sulfonylureas), missed or delayed meals, or unexpected physical activity. The body responds with a catecholamine surge first: tremors, diaphoresis, tachycardia, pallor, anxiety, and hunger. These adrenergic symptoms are the early warning. As glucose continues to drop, neuroglycopenic symptoms appear: confusion, slurred speech, irritability, seizures, and loss of consciousness. The Rule of 15 governs treatment in a conscious patient: give 15 grams of fast-acting carbohydrate (4 oz juice, glucose tablets), recheck glucose in 15 minutes, and repeat if still below 70. Once glucose normalizes, follow with a complex carbohydrate-protein snack to sustain levels. For an unconscious or NPO patient, never give oral carbohydrates — aspiration risk is immediate. Administer IV dextrose (D50 in adults) or glucagon IM/SubQ if no IV access. Glucagon works by mobilizing hepatic glycogen, so it may be ineffective in malnourished or alcohol-dependent patients with depleted stores.

Key Distinctions

Don't confuse adrenergic symptoms (sweating, tremor, tachycardia) with neuroglycopenic symptoms (confusion, seizure, coma) — adrenergic come first and are the window to intervene. Students mix up the Rule of 15 with DKA fluid protocols; they're unrelated emergencies with opposite glucose problems. Beta-blockers mask adrenergic warning signs, so a patient on propranolol may progress to neuroglycopenia without the usual tremor or tachycardia cues.

Clinical Pearl

Conscious = candy (oral glucose). Unconscious = can't swallow — go IV or glucagon. Never put anything in the mouth of an unresponsive hypoglycemic patient.