Endocrinology Boards: The Conditions You Cannot Afford to Miss

Endocrinology makes up roughly 10% of ABFM content, but its clinical footprint is larger than that — diabetes alone touches cardiology, nephrology, ophthalmology, and preventive care. Knowing endocrinology well gives you disproportionate returns on the exam.

This is the focused high-yield list.

Type 2 Diabetes: The ADA Standards You Must Know

Diagnosis - A1c ≥6.5%, or - Fasting glucose ≥126, or - 2-hr OGTT ≥200, or - Random glucose ≥200 with symptoms

Confirm abnormal result with a repeat test unless unambiguously symptomatic.

A1c Targets - General target: <7.0% for most nonpregnant adults - Stricter (<6.5%): younger, shorter-duration DM, low hypoglycemia risk - Looser (<8.0%): severe hypoglycemia history, limited life expectancy, advanced comorbidities

First-Line Therapy Metformin unless contraindicated (eGFR <30). Start 500 mg daily, titrate up.

Second Agent — This Is Where ABFM Loves to Test The answer now depends on comorbidities, not just A1c:

- Established ASCVD or high ASCVD risk: GLP-1 RA (semaglutide, liraglutide) or SGLT2i (empagliflozin, dapagliflozin) - Heart failure (HFrEF or HFpEF): SGLT2 inhibitor - CKD (especially with albuminuria): SGLT2 inhibitor (or GLP-1 RA if SGLT2 contraindicated) - Weight loss priority: GLP-1 RA - Cost priority: sulfonylurea or TZD

Type 1 Diabetes Red Flags - DKA precipitants: infection, nonadherence, MI, new-onset T1DM - Treatment essentials: IV fluids, insulin drip, potassium replacement, treat precipitant - Close gap: anion gap closure matters more than glucose normalization for stopping insulin drip transition

Thyroid Disorders

Hypothyroidism - TSH elevated, free T4 low → primary hypothyroidism - TSH low, free T4 low → central (secondary) hypothyroidism — rare, investigate pituitary - Treatment: levothyroxine 1.6 mcg/kg/day, titrate by TSH every 6 weeks - Subclinical: treat if TSH 10, symptomatic, positive TPO antibodies, or planning pregnancy

Hyperthyroidism - Graves: diffuse goiter, ophthalmopathy, positive TSI - Toxic multinodular goiter / adenoma: elderly, irregular thyroid - Thyroiditis: tender gland, self-limiting, may follow viral illness - RAIU scan differentiates (high in Graves, patchy in toxic MNG, low in thyroiditis) - Treatment: methimazole first-line for Graves; radioactive iodine or surgery if refractory; PTU preferred in first trimester of pregnancy

Thyroid Nodule Workup - TSH first - If TSH normal or high → ultrasound → FNA based on size + features - If TSH low → RAIU scan (hot nodule = rarely malignant, treat functionally)

Adrenal Disorders

Cushing Syndrome Screening tests (any one): - 24-hour urinary free cortisol - Late-night salivary cortisol - 1 mg overnight dexamethasone suppression test

Confirm before localization. ACTH level then differentiates ACTH-dependent (pituitary or ectopic) vs independent (adrenal).

Primary Adrenal Insufficiency (Addison) - Hyperpigmentation, hyperkalemia, hyponatremia, low cortisol, elevated ACTH - ACTH stimulation test confirms - Treatment: hydrocortisone + fludrocortisone; stress-dose steroids for illness

Primary Hyperaldosteronism - Suspect: resistant HTN, hypokalemia, adrenal incidentaloma - Screening: aldosterone-to-renin ratio (ARR) 20 suggestive - Confirm with sodium loading or saline infusion test

Osteoporosis

Screening (USPSTF) - Women ≥65 - Postmenopausal women <65 with elevated risk (FRAX ≥9.3% for major osteoporotic fracture) - Currently insufficient evidence for men (2018 USPSTF)

Treatment Thresholds Start pharmacologic therapy if: - T-score ≤-2.5 (hip, femoral neck, or spine), or - Osteopenia (T -1.0 to -2.5) + FRAX hip fracture risk ≥3% or major osteoporotic fracture risk ≥20%, or - History of hip or vertebral fracture

First-Line Agents Bisphosphonates (alendronate, risedronate, zoledronic acid). Denosumab, teriparatide, or romosozumab for high-risk or bisphosphonate failure.

Calcium 1,200 mg/day and vitamin D 800-1,000 IU/day as baseline.

Polycystic Ovary Syndrome (PCOS)

Rotterdam criteria (need 2 of 3): 1. Oligo/anovulation 2. Hyperandrogenism (clinical or biochemical) 3. Polycystic ovaries on ultrasound

Management pillars: - Lifestyle (weight loss — even 5-10% dramatically improves cycles) - Combined OCP for menstrual regulation and androgen symptoms - Metformin for insulin resistance / prediabetes - Letrozole first-line for ovulation induction in patients seeking pregnancy

Hyperparathyroidism

Primary: elevated calcium + elevated/inappropriately-normal PTH.

Surgical indications (any one): - Symptomatic (kidney stones, fractures, osteoporosis) - Age <50 - Calcium 1 mg/dL above upper limit - Creatinine clearance <60 - T-score ≤-2.5 at any site or vertebral fracture

Hyperprolactinemia

- Rule out pregnancy and medications first (antipsychotics, metoclopramide, verapamil, SSRIs) - Then MRI pituitary - Prolactinomas respond well to dopamine agonists (cabergoline preferred over bromocriptine) - Surgery reserved for resistant cases or macroadenomas with visual symptoms

Quick-Fire Numbers to Memorize

Condition Key Number --- --- A1c general target <7.0% Metformin cutoff eGFR <30 TSH treatment threshold (subclinical) 10 Osteoporosis T-score ≤-2.5 FRAX major fracture risk ≥20% Cushing screening DST cortisol 1.8 mcg/dL

Closing Thought

Endocrinology on the ABFM rewards guideline fluency more than any other domain. Feed these numbers into your spaced repetition queue early and let them become automatic. When exam day comes, you want these to feel like knowing your own phone number.