Endocrinology High-Yield: Diabetes, Thyroid, and Adrenal for FNP Boards

Clinical High-Yield · 10 min read · May 1, 2026

Why Endocrinology Is a Board Goldmine

Endocrinology questions appear consistently across both AANP and ANCC exams. The good news: the boards test a finite set of conditions in predictable ways. Master this framework and you'll pick up points reliably.

Diabetes Mellitus

Diagnosis

  • Fasting glucose ≥126 mg/dL on two occasions
  • Random glucose ≥200 mg/dL with symptoms
  • HbA1c ≥6.5% on two occasions
  • 2-hour glucose ≥200 mg/dL on OGTT

Management Hierarchy

First-line: Metformin (unless contraindicated — eGFR <30, contrast dye, liver disease, alcohol use).

Add-on agents — know the board favorites:

  • GLP-1 agonists (semaglutide, liraglutide): Weight loss, cardiovascular benefit, injectable. First choice add-on for patients with CVD or obesity.
  • SGLT-2 inhibitors (empagliflozin, dapagliflozin): Cardiovascular and renal protection. Risk: UTIs, DKA (rare), Fournier's gangrene.
  • Sulfonylureas (glipizide, glimepiride): Cheap, effective, but cause hypoglycemia and weight gain.
  • DPP-4 inhibitors (sitagliptin): Weight-neutral, low hypoglycemia risk.
  • Insulin: Required for Type 1. Used in Type 2 when other agents fail.

HbA1c Targets

  • Most adults: <7%
  • Elderly, limited life expectancy, hypoglycemia-prone: <8%
  • Tight control in pregnancy: <6.5%

Thyroid Disease

Hypothyroidism

Primary: TSH elevated, free T4 low. Most common cause: Hashimoto's thyroiditis (autoimmune, anti-TPO antibodies).

Treatment: Levothyroxine. Monitor TSH every 6–8 weeks until stable, then annually. Take on empty stomach, 30–60 minutes before food.

Subclinical: TSH elevated, normal free T4. Treat if TSH >10, symptomatic, pregnant, or planning pregnancy.

Hyperthyroidism

Graves' disease: Most common. Diffuse goiter, exophthalmos, pretibial myxedema. TSH suppressed, free T4/T3 elevated. Positive TSI antibodies.

Treatment options: Methimazole (PTU in first trimester), radioactive iodine ablation, thyroidectomy.

Thyroid storm: Emergency. Fever, tachycardia, altered mental status. Treat with PTU, beta-blockers, steroids, iodine (in that order).

Thyroid Nodules

Single nodule: TSH first. If TSH low → thyroid scan. If TSH normal/high → ultrasound. Biopsy if >1 cm with suspicious features.

Adrenal Disorders

Cushing's Syndrome

Excess cortisol. Causes: exogenous steroids (most common), pituitary adenoma (Cushing's disease), adrenal adenoma, ectopic ACTH.

Classic presentation: Central obesity, moon face, buffalo hump, purple striae, hypertension, hyperglycemia, easy bruising, proximal muscle weakness.

Screening: 24-hour urine free cortisol, late-night salivary cortisol, or 1 mg overnight dexamethasone suppression test.

Addison's Disease

Primary adrenal insufficiency. Autoimmune destruction most common cause.

Classic presentation: Fatigue, weight loss, hyperpigmentation (especially skin folds, gums, scars), hypotension, hyponatremia, hyperkalemia.

Diagnosis: Morning cortisol, ACTH stimulation t...