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2.4 Thyrotoxicosis, Thyroid Storm & Thyroid Nodules

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ABIM Internal Medicine Exam

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1 Chapter 0: The ABIM Exam, Blueprint & Study Strategy

0.1 Exam Format, Question Types & the 2026 Blueprint 0.2 Eligibility, Registration, Fees & Exam-Day Logistics 0.3 Scoring, the Passing Standard & Score Reports 0.4 Building a Blueprint-Weighted Study Plan

2 Chapter 1: Cardiovascular Disease (14% of Exam)

1.1 Ischemic Heart Disease & Acute Coronary Syndromes 1.2 Antithrombotic Therapy, Secondary Prevention & Mechanical Complications of MI 1.3 Atrial Fibrillation, Atrial Flutter & Stroke Prevention 1.4 Supraventricular Tachycardias, Ventricular Arrhythmias & Bradycardias 1.5 Heart Failure: Classification, Staging & Guideline-Directed Medical Therapy 1.6 Device Therapy, HFpEF & the Cardiomyopathies 1.7 Valvular Heart Disease & Endocarditis Prophylaxis 1.8 Pericardial Disease & Acute Aortic Syndromes 1.9 Hypertension: Classification, Diagnosis & Secondary Causes 1.10 Hypertensive Crises & Dyslipidemia 1.11 Adult Congenital Heart Disease & Coarctation of the Aorta 1.12 Syncope: Reflex, Orthostatic & Cardiac Causes 1.13 Cardiac Physical Examination, Murmurs & Antithrombotic Selection

3 Chapter 2: Endocrinology, Diabetes & Metabolism (9% of Exam)

2.1 Diabetes Mellitus: Diagnosis, Glycemic Targets & Pharmacotherapy 2.2 Insulin Therapy, Hyperglycemic Emergencies & Chronic Complications 2.3 Thyroid Function Testing & Hypothyroidism 2.4 Thyrotoxicosis, Thyroid Storm & Thyroid Nodules 2.5 Adrenal & Pituitary Disorders 2.6 Hypercalcemia, Hypocalcemia & Disorders of Mineral Metabolism 2.7 Osteoporosis & Paget Disease of Bone 2.8 Ovarian, Testicular & Reproductive Endocrine Disorders 2.9 Hypoglycemia, Endocrine Tumors, Polyglandular Syndromes & Severe Hypertriglyceridemia

4 Chapter 3: Gastroenterology & Hepatology (9% of Exam)

3.1 Esophageal Disease 3.2 Stomach & Duodenal Disease and Gastrointestinal Hemorrhage 3.3 Inflammatory Bowel Disease 3.4 Celiac Disease & Irritable Bowel Syndrome 3.5 Diverticular Disease & Colorectal Cancer Screening 3.6 Viral Hepatitis, Steatotic & Alcohol-Associated Liver Disease 3.7 Cirrhosis & the Complications of Portal Hypertension 3.8 Acute Pancreatitis 3.9 Chronic Pancreatitis & Biliary Tract Disease 3.10 Inherited, Autoimmune & Drug-Induced Liver Disease 3.11 Small Intestinal Disease, Ischemia & Gastrointestinal Complications of HIV

5 Chapter 4: Infectious Disease (9% of Exam)

4.1 Lower Respiratory Tract Infections & Sepsis Syndromes 4.2 Viral Respiratory Pathogens & Tuberculosis 4.3 Central Nervous System Infections 4.4 Skin, Soft Tissue, Bone & Joint Infections 4.5 Infective Endocarditis & Cardiovascular Infection 4.6 Clostridioides difficile & Catheter-Related Bloodstream Infection 4.7 HIV Diagnosis, Antiretroviral Therapy & Prevention 4.8 Opportunistic Infections & Sexually Transmitted Infections 4.9 Fever of Unknown Origin, Neutropenic Fever & Toxic Shock 4.10 Travel-Related Illness, Vector-Borne Disease & Outbreaks 4.11 Infection Prevention, Nosocomial Infection & Postexposure Prophylaxis 4.12 Rheumatic Fever, Poststreptococcal Disease, Enteric & Hepatic Infections

6 Chapter 5: Pulmonary Disease (9% of Exam)

5.1 COPD: Diagnosis, GOLD Classification & Initial Pharmacotherapy 5.2 Interventions That Reduce COPD Mortality & Exacerbation Management 5.3 Asthma: Diagnosis, Stepwise Therapy & Status Asthmaticus 5.4 Interstitial Lung Disease & Idiopathic Pulmonary Fibrosis 5.5 Sarcoidosis, Hypersensitivity Pneumonitis & Occupational Lung Disease 5.6 Pulmonary Embolism: Diagnosis, Risk Stratification & Anticoagulation 5.7 Pulmonary Hypertension & Sleep-Disordered Breathing 5.8 Acute Respiratory Distress Syndrome & Mechanical Ventilation 5.9 Pleural Disease, Empyema & Pneumothorax 5.10 Bronchiectasis, Cystic Fibrosis & Restrictive Lung Disease 5.11 Evaluation of Cough, Dyspnea, Hemoptysis & the Solitary Pulmonary Nodule

7 Chapter 6: Rheumatology & Orthopedics (9% of Exam)

6.1 Rheumatoid Arthritis: Diagnosis & Systemic Manifestations 6.2 Antirheumatic Pharmacotherapy & the Spondyloarthropathies 6.3 Gout: Pathophysiology & Acute Management 6.4 Urate-Lowering Therapy & Calcium Pyrophosphate Deposition Disease 6.5 Osteoarthritis 6.6 Systemic Lupus Erythematosus 6.7 Systemic Sclerosis, Sjogren Syndrome & Inflammatory Myopathies 6.8 The Vasculitides 6.9 Regional Musculoskeletal Syndromes, Back Pain & Sports Injuries 6.10 Other Primary Rheumatic Disorders & Mixed Connective Tissue Disease 6.11 Osteonecrosis & Metabolic Bone Disease

8 Chapter 7: Hematology (6% of Exam)

7.1 Approach to Anemia & the Microcytic Anemias 7.2 Macrocytic, Normocytic & Hemolytic Anemias 7.3 Hemoglobinopathies, Thalassemias & Paroxysmal Nocturnal Hemoglobinuria 7.4 Platelet Disorders, Thrombocytopenia & the Bleeding Patient 7.5 Coagulation Factor Disorders, Thrombophilia & Anticoagulant Reversal 7.6 Acute Leukemias, Chronic Leukemias & Myeloproliferative Neoplasms 7.7 Lymphomas & Plasma Cell Disorders 7.8 Myelodysplastic Syndrome, Myeloproliferative Neoplasms & Porphyria 7.9 Transfusion Medicine & Late Complications of Transplantation

9 Chapter 8: Medical Oncology (6% of Exam)

8.1 Breast, Lung, Colorectal & Prostate Cancer 8.2 Oncologic Emergencies 8.3 Genitourinary & Gynecologic Malignancies 8.4 Head and Neck, Bone & Soft Tissue Cancer and Cancer of Unknown Primary 8.5 Complications of Cancer & Its Treatment 8.6 Cancer Prevention, Survivorship & Psychosocial Care

10 Chapter 9: Nephrology & Urology (6% of Exam)

9.1 Acute Kidney Injury: Staging, Etiology & Urine Microscopy 9.2 Glomerular Disorders & Nephrotic Syndrome 9.3 Nephritic Syndromes, RPGN & Indications for Renal Replacement Therapy 9.4 Chronic Kidney Disease: Staging & Progression Retardation 9.5 Complications of Chronic Kidney Disease: Anemia, CKD-MBD & Acidosis 9.6 Hyponatremia, Hypernatremia & Water Balance 9.7 Potassium Disorders & Systematic Acid-Base Analysis 9.8 Renal Tubular Acidosis & Nephrolithiasis 9.9 Prostate Disorders, Urinary Incontinence & Other Urologic Conditions 9.10 Cystic Kidney Disease, Obstructive Uropathy, Tubulointerstitial Disease & Hematuria

11 Chapter 10: Neurology (4% of Exam)

10.1 Acute Ischemic Stroke: Syndromes & Reperfusion 10.2 Transient Ischemic Attack, Secondary Prevention & Hemorrhagic Stroke 10.3 Headache & Facial Pain 10.4 Seizures, Epilepsy & Movement Disorders 10.5 Multiple Sclerosis & Neuromuscular Junction Disorders 10.6 Motor Neuron Disease & Acute Peripheral Neuropathy 10.7 Cranial Neuropathies & Neuro-Ophthalmology 10.8 Peripheral Neuropathies, CNS Tumors & Other Neurologic Disorders

12 Chapter 11: Psychiatry & Behavioral Health (4% of Exam)

11.1 Major Depressive Disorder & Medical Mimics 11.2 Antidepressant Pharmacotherapy & Treatment-Resistant Depression 11.3 Bipolar Disorder, Mood Stabilizers & Lithium Toxicity 11.4 Anxiety, Stress-Related & Obsessive-Compulsive Disorders 11.5 Alcohol Use Disorder & Withdrawal 11.6 Pharmacotherapy for Alcohol & Opioid Use Disorder 11.7 Toxidromes, Psychiatric Emergencies & Suicide Risk Assessment 11.8 Psychotic, Somatic Symptom, Factitious & Personality Disorders 11.9 Eating Disorders, Sleep Disorders & Sexual Health

13 Chapter 12: Dermatology (3% of Exam)

12.1 Dermatitis, Papulosquamous & Inflammatory Dermatoses 12.2 Acne, Rosacea & Cutaneous Infections 12.3 Herpes Zoster & Autoimmune Blistering Diseases 12.4 Nodules, Tumors & Cutaneous Oncology 12.5 Dermatologic Emergencies & Severe Cutaneous Adverse Reactions 12.6 Pigment Disorders, Alopecia, Nail Disease & Photosensitivity 12.7 Vascular Dermatoses, Environmental Injury & Cutaneous Signs of Systemic Disease

14 Chapter 13: Obstetrics & Gynecology / Women's Health (3% of Exam)

13.1 Contraception, Preconception Care & Teratogenicity 13.2 Hypertensive Disorders of Pregnancy & Gestational Diabetes 13.3 Thyroid Disease & Venous Thromboembolism in Pregnancy 13.4 Menopause & Menopausal Hormone Therapy 13.5 Abnormal Uterine Bleeding, Endometrial Disease & Gynecologic Cancer Screening 13.6 Breast Disorders & Diseases of the Vulva and Vagina 13.7 Menstrual Disorders, Fibroids, Endometriosis & Early Pregnancy Complications

15 Chapter 14: Geriatric Syndromes (3% of Exam)

14.1 Comprehensive Geriatric Assessment & Frailty 14.2 Falls, Gait Assessment & Polypharmacy 14.3 Urinary Incontinence & Pressure Injuries in Older Adults 14.4 Mild Cognitive Impairment, Dementia & Its Subtypes 14.5 Delirium & the Pharmacotherapy of Cognitive Disorders 14.6 Palliative Care, Hospice & Advance Care Planning 14.7 Chronic Wounds, Nutrition, Swallowing, Constipation & Hip Fracture 14.8 Sensory Impairment, Dizziness, Elder Mistreatment & Care Settings

16 Chapter 15: Allergy & Immunology (2% of Exam)

15.1 Anaphylaxis: Recognition & Emergency Management 15.2 Urticaria & Angioedema 15.3 Drug Allergy, Desensitization & Adult Immunodeficiency 15.4 Food Allergy, Insect Venom Hypersensitivity, Serum Sickness & Contrast Reactions 15.5 Rhinitis, Conjunctivitis, Eosinophilic & Mast Cell Disorders

17 Chapter 16: Preventive Medicine, Immunization & Clinical Epidemiology

16.1 The USPSTF Framework & Evidence-Based Cancer Screening 16.2 Cardiovascular & Metabolic Screening and Primary Prevention 16.3 Adult Immunization & Vaccines in Special Populations 16.4 Clinical Epidemiology, Biostatistics & Study Design

18 Chapter 17: Miscellaneous - Ethics, Patient Safety & Quality Improvement (2% of Exam)

17.1 Principles of Bioethics & Decisional Capacity 17.2 Informed Consent, Treatment Refusal & Special Scenarios 17.3 Surrogate Decision-Making, Advance Directives & Confidentiality 17.4 Patient Safety Science, Medical Error & Diagnostic Reasoning 17.5 Quality Improvement Methods, Health Disparities & Health Equity

19 Chapter 18: Perioperative Medicine & Medical Consultation

18.1 Preoperative Cardiovascular Risk Assessment 18.2 Preoperative Pulmonary Risk & Perioperative Medication Management 18.3 Perioperative Anticoagulation, Bridging & Postoperative Complications

20 Chapter 19: Ophthalmology (1% of Exam)

19.1 The Acute Red Eye & Ophthalmic Emergencies 19.2 Painless Vision Loss & Chronic Ophthalmic Disease 19.3 Uveitis, Scleritis & Orbital Disease

21 Chapter 20: Otolaryngology & Dental Medicine (1% of Exam)

20.1 Dizziness, Vertigo & Epistaxis 20.2 Ear Disorders, Hearing Loss & Upper Respiratory Infections 20.3 Oral Cavity, Salivary Gland, Laryngeal & Taste and Smell Disorders

2.4 Thyrotoxicosis, Thyroid Storm & Thyroid Nodules

Key Takeaways Explain This Topic AI

Radioiodine uptake separates high-uptake thyrotoxicosis such as Graves disease from low-uptake causes such as thyroiditis and exogenous hormone.

Painful thyroiditis with low uptake is treated symptomatically with beta-blockade and anti-inflammatory therapy, not with thionamides.

Thyroid storm is a clinical diagnosis; treatment blocks synthesis, release, peripheral conversion and adrenergic effect, and iodine must follow rather than precede thionamide administration.

A thyroid nodule with a normal or elevated thyroid-stimulating hormone is evaluated by ultrasound and risk-stratified aspiration rather than by scintigraphy.

Fine-needle aspiration cytology must be obtained before thyroidectomy because it determines the extent of surgery.

Last updated: August 2026

1. Thyrotoxicosis: Differential Diagnosis & Graves Management

Thyrotoxicosis represents excessive circulating thyroid hormone, whereas hyperthyroidism specifically denotes increased de novo thyroid hormone synthesis by the gland.

Diagnostic Distinction via Radioactive Iodine Uptake (RAIU) +-------------------------------------------------------------------------------------------------------------+

| RAIU PATTERN | ETIOLOGY & PATHOPHYSIOLOGY | CLINICAL FEATURES & THERAPY |

+------------------------------+----------------------------------------------+-------------------------------+

  • | HIGH / NORMAL UPTAKE | 1. Graves Disease | - TSI / TRAb positive (>95%) |
  • | (Active De Novo Synthesis) | - Diffuse homogenous uptake (40-80%) | - Exophthalmos, pretibial |
  • | | - Autoantibodies stimulate TSH receptor | myxedema, thyroid bruit |
  • | | 2. Toxic Multinodular Goiter (Plummer) | - Patchy, heterogeneous uptake|
  • | | - Multiple autonomous hyperactive nodules | - Elderly, compressive goiter |
  • | | 3. Toxic Adenoma | - Single hot focal nodule with|
  • | | - Single somatic TSH receptor mutation | suppression of remainder |

+------------------------------+----------------------------------------------+-------------------------------+

  • | LOW / ABSENT UPTAKE (< 2%) | 1. Subacute Granulomatous Thyroiditis | - Painful, exquisitely tender |
  • | (Follicular Destruction | (de Quervain / giant-cell thyroiditis) | goiter; elevated ESR/CRP; |
  • | or Exogenous Source) | - Post-viral inflammatory release | treat with NSAIDs/Steroids |
  • | | 2. Subacute Lymphocytic (Painless) / | - Non-tender goiter; self- |
  • | | Postpartum Thyroiditis | limiting; beta-blockers |
  • | | 3. Exogenous / Factitious Thyrotoxicosis | - Low serum Thyroglobulin; |
  • | | - Ingestion of thyroid hormone | RAIU < 1% |
  • | | 4. Struma Ovarii | - Ectopic teratoma; pelvic |
  • | | - Ovarian teratoma producing T4 | scintigraphy uptake |

+------------------------------+----------------------------------------------+-------------------------------+

Graves Disease Management Modalities

Antithyroid Drugs (ATDs):

Methimazole (MMI): Drug of choice for almost all non-pregnant adults and during the 2nd and 3rd trimesters of pregnancy (superior potency, once-daily dosing, lower hepatotoxicity risk than PTU).

Propylthiouracil (PTU): Preferred ONLY during the 1st trimester of pregnancy (due to MMI teratogenicity: aplasia cutis, choanal atresia) and in Thyroid Storm (due to inhibition of peripheral 5'-deiodinase converting T4 to T3).

Critical Adverse Effects: Agranulocytosis (absolute neutrophil count < 500/mcL in 0.3–0.5%; presents with sudden fever and severe sore throat -> instruct patients to stop ATD immediately and obtain a stat CBC with differential ); Hepatotoxicity (PTU causes fulminant hepatic necrosis; MMI causes cholestatic jaundice); ANCA-associated vasculitis.

Radioactive Iodine (RAI / I-131 Ablation):

First-line definitive therapy in the United States. Concentrates in thyroid tissue, inducing cell destruction over 6–18 weeks.

Absolute Contraindications: Pregnancy and breastfeeding.

Relative Contraindication: Moderate-to-severe active Graves Orbitopathy (RAI increases TSH receptor antibody titers and worsens ophthalmopathy; administer prophylactic oral Prednisone 0.4–0.5 mg/kg/day if mild orbitopathy undergoing RAI).

Total Thyroidectomy: Indicated for large compressive goiters, coexisting suspicious malignant nodules, moderate-to-severe active Graves orbitopathy, or patient preference/ATD failure.

Loading diagram... Algorithmic Workup of Thyroid Nodules

2. Thyroid Storm: Burch-Wartofsky Score & 5-Step Emergency Therapy

Thyroid storm is an acute, life-threatening manifestation of thyrotoxicosis with a mortality rate of 10–30%. It is diagnosed clinically using the Burch-Wartofsky Point Scale (BWPS >=45 is highly suggestive) , assessing thermoregulatory dysfunction (fever up to 40°C / 104°F), central nervous system effects (agitation, delirium, psychosis, coma), cardiovascular dysfunction (tachycardia >140 bpm, atrial fibrillation, congestive heart failure), and gastrointestinal-hepatic dysfunction (diarrhea, jaundice, abdominal pain).

5-Step Multimodal Pharmacotherapy Protocol +-------------------------------------------------------------------------------------------------------------+

| STEP & CLASS | DRUG & DOSAGE | PHYSIOLOGICAL MECHANISM & CRITICAL RULES |

+---------------------+-----------------------------+---------------------------------------------------------+

  • | 1. Beta-Blocker | Propranolol 60-80 mg PO q4h | Blocks beta-1 and beta-2 adrenergic receptors; |
  • | | OR Esmolol IV infusion | High-dose propranolol inhibits peripheral 5'-deiodinase |
  • | | | conversion of T4 to active T3 |

+---------------------+-----------------------------+---------------------------------------------------------+

  • | 2. Thionamide | PTU 500-1000 mg loading PO, | Blocks de novo thyroid hormone synthesis; PTU also |
  • | (Antithyroid) | then 250 mg PO q4h | blocks peripheral T4-to-T3 conversion; |
  • | | (OR Methimazole 20-30 mg q6h| Administer BEFORE inorganic iodine! |

+---------------------+-----------------------------+---------------------------------------------------------+

  • | 3. Inorganic Iodine | Potassium Iodide (SSKI) | Wolff-Chaikoff effect: acutely blocks thyroid hormone |
  • | (Iodide block) | 5 drops PO q6h | release from colloid; |
  • | | OR Lugol Solution 8 drops q6| CRITICAL RULE: MUST WAIT AT LEAST 1 HOUR AFTER |
  • | | | THIONAMIDE! Giving iodine first fuels hormone synthesis |
  • | | | (Jod-Basedow phenomenon) and worsens thyroid storm. |

+---------------------+-----------------------------+---------------------------------------------------------+

  • | 4. Glucocorticoids | Hydrocortisone 100 mg IV q8h| Inhibits peripheral T4-to-T3 conversion; treats relative|
  • | | OR Dexamethasone 2 mg IV q6h| vasomotor adrenal exhaustion; stabilizes vasomotor tone |

+---------------------+-----------------------------+---------------------------------------------------------+

  • | 5. Supportive & | Bile acid sequestrants | Cholestyramine (4g PO qID) enhances fecal excretion of |
  • | Fecal Clearance | (Cholestyramine); | circulating thyroid hormone; Acetaminophen and cooling |
  • | | Cooling blankets; IV fluids | blankets for fever; AVOID SALICYLATES/ASPIRIN (displaces|
  • | | | T4/T3 from thyroid-binding globulin, increasing free T4)|

+---------------------+-----------------------------+---------------------------------------------------------+

  • 3. Thyroid Nodules & Malignancy Subtypes
  • Thyroid Malignancy Classification

Papillary Thyroid Carcinoma (PTC) (~85% of all thyroid cancers):

Histopathology: Orphan Annie eye nuclei (cleared, optically empty nuclei), psammoma bodies (laminated calcospherites), nuclear pseudoinclusions, and nuclear grooving.

Behavior: Spreads via lymphatics to regional cervical lymph nodes; distant metastases rare; excellent 10-year survival rate (>95%).

Management: Lobectomy (for unifocal tumors <1–4 cm without extrathyroidal extension or nodal involvement) vs Total Thyroidectomy +/- central neck lymph node dissection, followed by postop Radioactive Iodine (RAI) ablation for high-risk features and TSH suppression with levothyroxine.

Follicular Thyroid Carcinoma (FTC) (~10%):

Histopathology: Composed of uniform follicular cells. Cannot be diagnosed by FNA biopsy (FNA cannot distinguish benign follicular adenoma from carcinoma because diagnosis requires histological demonstration of capsular or vascular invasion ).

Behavior: Spreads hematogenously to bone and lungs.

Management: Diagnostic lobectomy; if pathology demonstrates capsular/vascular invasion, completion thyroidectomy followed by RAI ablation.

Medullary Thyroid Carcinoma (MTC) (~3–5%):

Pathophysiology: Neuroendocrine tumor derived from calcitonin-secreting parafollicular C-cells (neural crest origin). Amyloid stroma on histology.

Genetics: 25% are hereditary, caused by germline RET proto-oncogene mutations as part of MEN 2A (MTC, Pheochromocytoma, Primary Hyperparathyroidism) or MEN 2B (MTC, Pheochromocytoma, Mucosal neuromas, Marfanoid habitus).

Tumor Markers: Serum Calcitonin (correlates with tumor burden) and Carcinoembryonic Antigen (CEA) .

MANDATORY EXAM RULE: Before performing neck surgery on newly diagnosed MTC, always screen for Pheochromocytoma (plasma free metanephrines). If pheochromocytoma is present, resect the pheochromocytoma FIRST to prevent intraoperative hypertensive crisis. MTC does NOT concentrate radioactive iodine.

Anaplastic (Undifferentiated) Thyroid Carcinoma (ATC) (~1–2%):

Behavior: Highly aggressive malignancy in elderly patients presenting with a rapidly enlarging anterior neck mass , severe compressive symptoms (dysphagia, stridor, hoarseness from vocal cord paralysis), and early local/distant invasion. Median survival is 3–6 months.

Management: Airway protection/palliative tracheostomy, radiation, and targeted therapy (Dabrafenib + Trametinib if BRAF V600E-mutated).