8.1 Endocrine Assessment & Diabetes Management

Diabetes mellitus is the highest-yield endocrine topic on the MEDSURG-BC exam. Questions test your ability to interpret diagnostic labs, match insulin types to their action profiles, and prioritize care in the hyperglycemic emergencies.

Types of Diabetes

• Type 1 diabetes mellitus (T1DM): Autoimmune destruction of pancreatic beta cells causing absolute insulin deficiency. Onset is usually in childhood or young adulthood, patients are typically lean, and they are prone to diabetic ketoacidosis (DKA). Lifelong insulin is required.
• Type 2 diabetes mellitus (T2DM): Insulin resistance with progressive beta-cell dysfunction. Strong association with obesity and sedentary lifestyle; patients may be managed with oral agents, non-insulin injectables, or insulin. The characteristic emergency is hyperosmolar hyperglycemic state (HHS).
• Gestational diabetes: Glucose intolerance first recognized in pregnancy; resolves after delivery but increases future T2DM risk.
• Prediabetes: A1C 5.7-6.4% or fasting glucose 100-125 mg/dL (impaired fasting glucose). This is a counseling and lifestyle-intervention window.

Diagnostic Criteria (American Diabetes Association)

Any one of the following, confirmed on a second day unless symptoms are unequivocal:

Glycemic targets for most nonpregnant adults: fasting/premeal glucose 80-130 mg/dL, peak postprandial under 180 mg/dL, and A1C under 7%. For hospitalized and critically ill patients, target 140-180 mg/dL — tight control in the ICU increases hypoglycemia risk without outcome benefit.

Insulin Types: Onset, Peak, Duration

The exam frequently asks which insulin to hold when a patient is NPO, which to give for a glucose of 320 mg/dL right now, or why a patient on evening NPH wakes up hypoglycemic.

Insulin pearls

• Only regular insulin is given IV — it is the insulin of choice for DKA and HHS drips.
• Give rapid-acting insulin within 15 minutes of eating; giving it to a patient whose tray has not arrived causes hypoglycemia.
• Long-acting basal insulin (glargine) is continued even when NPO, including for surgery; prandial (rapid/short-acting) insulin is held when the patient cannot eat.
• When mixing insulins, draw clear before cloudy (regular before NPH).
• NPH is the only insulin that looks cloudy; gently roll — do not shake — to resuspend it.

Hypoglycemia vs Hyperglycemia

Hypoglycemia is a blood glucose below 70 mg/dL and is the most immediately life-threatening glucose problem — treat it before anything else.

Memory aid: hypoglycemia signs are cold and clammy — need some candy. Severe signs (seizure, unconsciousness) reflect neuroglycopenia.

The 15/15 rule (conscious patient)

1. Give 15 grams of fast-acting carbohydrate: 4 oz fruit juice or regular soda, 3-4 glucose tablets, or 1 tablespoon of sugar or honey.
2. Recheck glucose in 15 minutes.
3. Repeat treatment until glucose is above 70 mg/dL.
4. If the next meal is more than an hour away, follow with a protein-and-carbohydrate snack.

Unconscious or NPO patient

• Give glucagon 1 mg IM or subcutaneous (also available as intranasal), or 25 g of 50% dextrose (D50) IV.
• Never give anything by mouth to a patient who cannot swallow.

Beta-blockers mask the adrenergic warning signs (tremor, tachycardia, palpitations) of hypoglycemia — sweating may be the only clue.

DKA vs HHS

Management priorities (both emergencies)

1. Fluids first: 0.9% sodium chloride at 15-20 mL/kg (about 1 L/hr initially). Fluid resuscitation restores perfusion and lowers glucose by dilution and improved renal clearance.
2. Regular insulin IV infusion at 0.1 units/kg/hr (DKA). Glucose should fall 50-70 mg/dL per hour; a slower drop suggests inadequate dosing or insulin resistance.
3. Potassium before or with insulin: Insulin drives potassium into cells, and acidosis masks total-body potassium depletion. If serum potassium is below 3.3 mEq/L, hold insulin and replace potassium first. If 3.3-5.2, add 20-30 mEq KCl per liter of fluid.
4. Add dextrose (D5-0.45% NS) when glucose reaches about 250 mg/dL and continue insulin until the anion gap closes and pH normalizes — stopping insulin when glucose normalizes but acidosis persists causes rebound DKA.
5. Search for the trigger: infection, missed insulin, new diagnosis, myocardial infarction, drugs (corticosteroids).

Complication to watch: cerebral edema (especially in children and young adults) from overly rapid correction — report headache or decreasing level of consciousness immediately.

Sick-Day Rules

Illness raises counterregulatory hormones and glucose even when the patient is not eating. Teach patients to:

• Never stop insulin — insulin needs typically increase during illness; omission is a leading cause of DKA.
• Check glucose every 4 hours and check urine ketones when glucose exceeds 240-300 mg/dL (type 1).
• Sip sugar-free fluids to prevent dehydration; if unable to tolerate solids, alternate sugar-containing fluids to cover insulin.
• Call the provider for vomiting, ketones, glucose persistently above 300 mg/dL, or signs of dehydration.

Foot Care

Peripheral neuropathy plus peripheral arterial disease makes the diabetic foot a major source of morbidity. Teach daily foot inspection (use a mirror for soles), washing with lukewarm water and thorough drying between toes, never walking barefoot, avoiding heating pads and hot water bottles (burn risk with neuropathy), cutting nails straight across, and wearing properly fitted shoes. The nurse screens with a 10-g monofilament for protective sensation and palpates pedal pulses; patients need a professional foot exam at least annually.

Chronic Complications

• Microvascular: Retinopathy (leading cause of adult blindness — annual dilated eye exam), nephropathy (microalbuminuria is the earliest sign; ACE inhibitors or ARBs are renoprotective), neuropathy (stocking-glove sensory loss, gastroparesis, neurogenic bladder).
• Macrovascular: Coronary artery disease, stroke, peripheral arterial disease — the leading cause of death in T2DM. Aggressive blood pressure and lipid management (statins) matter as much as glucose control.

Perioperative Glucose Management

• Continue basal insulin (often at 75-80% of the usual dose); hold prandial insulin while NPO.
• Hold metformin the day of surgery (lactic acidosis risk with hemodynamic changes and contrast dye) and restart once renal function is confirmed.
• Target glucose 140-180 mg/dL in surgical and critically ill patients; treat values above 180 with correction insulin and treat below 70 immediately.
• Frequent monitoring is required because anesthesia masks hypoglycemia symptoms.