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5.7 Pulmonary Hypertension & Sleep-Disordered Breathing

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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

5.7 Pulmonary Hypertension & Sleep-Disordered Breathing

Key Takeaways Explain This Topic AI

Sleep medicine is its own blueprint subsection listing obesity-hypoventilation syndrome, obstructive sleep apnea, insomnia and parasomnia.

Right heart catheterization is required to confirm pulmonary hypertension and to distinguish precapillary from postcapillary disease.

Pulmonary arterial vasodilators are indicated in group 1 disease and may cause harm in group 2 pulmonary hypertension due to left heart disease.

Chronic thromboembolic pulmonary hypertension is the one surgically curable form and is screened for with ventilation-perfusion scanning rather than computed tomographic angiography.

Obesity-hypoventilation syndrome is distinguished from obstructive sleep apnea by daytime hypercapnia and requires ventilatory support rather than continuous positive airway pressure alone in many patients.

Last updated: August 2026

1. Pulmonary Hypertension (PH) & Pulmonary Arterial Hypertension (PAH)

Pulmonary hypertension is a hemodynamic and pathophysiological condition defined by an elevation in pulmonary vascular pressures.

Updated Hemodynamic Definitions (2022 ESC/ERS Guidelines)

Pulmonary Hypertension (All Causes): Mean Pulmonary Artery Pressure ( mPAP > 20 mmHg ) at rest measured via invasive Right Heart Catheterization (RHC) .

Pre-Capillary Pulmonary Hypertension (Groups 1, 3, 4, 5):

  • mPAP > 20 mmHg
  • Pulmonary Capillary Wedge Pressure (PCWP) <= 15 mmHg (excludes left heart disease)
  • Pulmonary Vascular Resistance (PVR) > 2 Wood Units (WU)

Post-Capillary Pulmonary Hypertension (Group 2 - Left Heart Disease):

mPAP > 20 mmHg and PCWP > 15 mmHg .

Isolated Post-Capillary PH (IpcPH): PVR <= 2 WU.

Combined Post- and Pre-Capillary PH (CpcPH): PVR > 2 WU.

Clinical Classification (WHO Groups 1–5)

Group 1: Pulmonary Arterial Hypertension (PAH): Idiopathic, heritable (BMPR2 gene mutation), drug/toxin-induced (methamphetamines, aminorex, fenfluramine), connective tissue disease (Systemic Sclerosis / CREST syndrome >> SLE), HIV infection, portal hypertension (portopulmonary hypertension), congenital systemic-to-pulmonary shunts, schistosomiasis.

Group 2: PH Due to Left Heart Disease: Heart failure with preserved ejection fraction (HFpEF), heart failure with reduced ejection fraction (HFrEF), mitral/aortic valvular disease. Most common cause of PH overall (~70%).

Group 3: PH Due to Lung Diseases and/or Hypoxia: COPD, idiopathic pulmonary fibrosis, obstructive sleep apnea, chronic high-altitude exposure.

Group 4: Chronic Thromboembolic Pulmonary Hypertension (CTEPH): Persistent thromboembolic occlusion and remodeling of pulmonary arteries following PE. Screening test of choice: V/Q lung scan (shows multiple mismatched segmental perfusion defects; superior sensitivity to CTPA). Treatment of choice: Surgical Pulmonary Thromboendarterectomy (PTE) , which can be curative. For inoperable CTEPH: Balloon Pulmonary Angioplasty (BPA) and oral Riociguat .

Group 5: PH with Unclear/Multifactorial Mechanisms: Hematologic disorders (myeloproliferative neoplasms), systemic disorders (sarcoidosis, histiocytosis X), metabolic disorders (Gaucher disease), chronic renal failure on hemodialysis.

Targeted Pharmacotherapy for WHO Group 1 PAH

Patients with Group 1 PAH should undergo acute vasodilator testing during RHC with inhaled Nitric Oxide. If positive (fall in mPAP >=10 mmHg to <=40 mmHg with preserved cardiac output; ~10%), high-dose oral Calcium Channel Blockers (Diltiazem, Amlodipine) are indicated. Non-responders receive combination therapy targeting specific pathways:

Endothelin Receptor Antagonists (ERAs): Block vasoconstriction and vascular smooth muscle proliferation mediated by endothelin-1. Agents: Ambrisentan (selective ETA antagonist), Bosentan (dual ETA/ETB antagonist; requires monthly LFT monitoring due to hepatotoxicity), Macitentan .

Nitric Oxide / cGMP Enhancers:

Phosphodiesterase-5 (PDE-5) Inhibitors: Sildenafil , Tadalafil (inhibit cGMP degradation, promoting smooth muscle relaxation and vasodilation).

Soluble Guanylate Cyclase (sGC) Stimulator: Riociguat (directly stimulates sGC independently of NO). CRITICAL CONTRAINDICATION: Co-administration of Riociguat with PDE-5 inhibitors or nitrates is strictly contraindicated due to severe, potentially fatal systemic hypotension.

Prostacyclin Pathway Agonists: Stimulate IP receptors, increasing cAMP to induce potent vasodilation and platelet anti-aggregation. Agents: IV Epoprostenol (continuous infusion; gold-standard therapy for high-risk / NYHA Class IV PAH, proven to improve survival), subcutaneous/inhaled Treprostinil , oral Selexipag (selective non-prostanoid IP receptor agonist).

Activin Signaling Inhibitors: Sotatercept (first-in-class activin receptor type IIA-Fc fusion protein). Binds and traps activins and growth differentiation factors, rebalancing pro-proliferative activin signaling with anti-proliferative BMPR2 signaling. Proven in the STELLAR trial to significantly increase 6-minute walk distance, lower PVR, and reduce clinical worsening events.

  • 2. Sleep-Disordered Breathing: OSA vs. OHS
  • Obstructive Sleep Apnea (OSA)

Pathophysiology: Repetitive partial (hypopnea) or complete (apnea) collapse of the upper pharyngeal airway during sleep, resulting in paroxysmal arterial oxygen desaturation, surges in sympathetic tone, acute systemic/pulmonary arterial vasoconstriction, and sleep fragmentation.

Risk Factors: Obesity (BMI > 30 kg/m2), male sex, post-menopausal state, craniofacial disharmony (retrognathia, micrognathia, macroglossia, tonsillar hypertrophy), neck circumference > 17 inches (43 cm) in men, > 16 inches (40 cm) in women .

Screening: STOP-BANG Questionnaire (Snoring, Tiredness, Observed apnea, high blood Pressure, BMI > 35, Age > 50, Neck circumference, Gender male; score >=3 indicates intermediate-to-high risk).

Diagnostic Polysomnography (PSG): Quantifies the Apnea-Hypopnea Index (AHI) — total number of apneas (cessation of airflow >=10 seconds with persistent respiratory effort) plus hypopneas (airflow reduction >=30% with >=3% desaturation or arousal) per hour of sleep:

  • Normal: AHI < 5 events/hour
  • Mild OSA: AHI 5 – 14.9 events/hour
  • Moderate OSA: AHI 15 – 29.9 events/hour
  • Severe OSA: AHI >= 30 events/hour

Treatment:

Continuous Positive Airway Pressure (CPAP): First-line gold standard for moderate-to-severe OSA or symptomatic mild OSA.

Alternative Therapies: Oral Mandibular Advancement Devices (MAD) for mild-to-moderate OSA in patients intolerant of CPAP; Positional therapy; Hypoglossal Nerve Stimulation (implantable device for moderate-to-severe OSA with BMI < 35 kg/m2 without complete concentric palatal collapse); Weight loss (including GLP-1 receptor agonists / bariatric surgery).

Obesity Hypoventilation Syndrome (OHS / Pickwickian Syndrome)

Diagnostic Triad:

  • Obesity (BMI >= 30 kg/m2)
  • Awake, daytime chronic hypercapnia (arterial PaCO2 >= 45 mmHg) on room air arterial blood gas

Sleep-disordered breathing (OSA present in ~90% of patients; sleep hypoventilation in 10%) Exclusion criterion: Hypercapnia must not be attributable to another underlying condition (severe COPD, neuromuscular weakness, severe kyphoscoliosis).

Diagnostic Screening Pearl: An elevated serum bicarbonate level (HCO3- >= 27 mEq/L) on a routine basic metabolic panel reflects renal metabolic compensation for chronic nocturnal and daytime respiratory acidosis. In an obese patient, a serum HCO3- >= 27 mEq/L has >92% sensitivity for screening OHS and warrants diagnostic arterial blood gas testing.

Management: Positive airway pressure therapy (CPAP for concurrent severe OSA; Bilevel PAP / Non-Invasive Ventilation if hypoventilation persists despite CPAP or severe nocturnal desaturations); aggressive weight reduction.