Study guide
4.2 Viral Respiratory Pathogens & Tuberculosis
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
4.2 Viral Respiratory Pathogens & Tuberculosis
Key Takeaways Explain This Topic AI
Tuberculosis is enumerated under lower respiratory tract infections in both the Infectious Disease and Pulmonary Disease blueprint categories.
Active tuberculosis must be excluded before treating latent infection, because monotherapy in active disease generates resistance.
Isoniazid causes hepatotoxicity and pyridoxine-responsive peripheral neuropathy; ethambutol causes optic neuritis with loss of color discrimination.
Pyrazinamide causes hyperuricemia and hepatotoxicity, and rifampin causes orange discoloration of body fluids with extensive cytochrome P450 induction.
Antiviral therapy for influenza provides greatest benefit when started within 48 hours, but is still indicated for hospitalized or high-risk patients presenting later.
Last updated: August 2026
- 1. Viral Respiratory Pathogens: Influenza & COVID-19
- Influenza (Influenza A & B)
Clinical Presentation: Abrupt onset of high fever, rigors, myalgias, headache, non-productive cough, and prostration.
Diagnostics: Reverse-transcriptase PCR (RT-PCR) of nasopharyngeal swab (rapid molecular test of choice).
Antiviral Therapy:
Oseltamivir (Tamiflu): Neuraminidase inhibitor (75 mg PO BID for 5 days). Indicated for all hospitalized patients , individuals with severe/progressive illness, or high-risk outpatients (age >=65, pregnant/postpartum <2 weeks, chronic pulmonary/cardiac/renal/hepatic disease, immunosuppressed, BMI >=40) regardless of symptom duration. In healthy outpatients with uncomplicated influenza, treatment provides maximum benefit when started within <=48 hours of symptom onset.
Baloxavir marboxil (Xofluza): Cap-dependent endonuclease inhibitor administered as a single weight-based oral dose (40 mg for 40–79 kg; 80 mg for >=80 kg); effective alternative for outpatients within 48 hours.
Complications: Secondary bacterial pneumonia classically caused by Staphylococcus aureus (including MRSA) and Streptococcus pneumoniae ; suspect when a patient develops recrudescent fever, productive purulent sputum, and new pulmonary consolidation following initial influenza recovery.
COVID-19 (SARS-CoV-2)
Clinical Severity Definition & Clinical Criteria Recommended Pharmacotherapy
Mild-to-Moderate (Outpatient High Risk) SpO2 >=94% on room air, no dyspnea, but high risk for progression (age >=65, obesity, DM, CKD, immunosuppression) • First-Line: Nirmatrelvir-ritonavir (Paxlovid) 300/100 mg PO BID x 5 days initiated within 5 days of symptom onset. (Adjust dose to 150/100 mg BID for eGFR 30–59 mL/min; contraindicated if eGFR <30 mL/min).; Critical Check: Review CYP3A4 drug-drug interactions (contraindicated with simvastatin, amiodarone, rivaroxaban, tacrolimus, carbamazepine).; • Second-Line: IV Remdesivir (200 mg IV day 1, 100 mg IV days 2–3) initiated within 7 days of symptom onset.
Hospitalized Requiring Supplemental Oxygen SpO2 <94% on room air requiring low-flow nasal cannula O2 • Dexamethasone 6 mg IV/PO daily for up to 10 days (or until discharge) PLUS ; • Remdesivir 200 mg IV day 1, then 100 mg IV daily for 5 days (extend to 10 days if intubated).
Hospitalized on High-Flow Oxygen / NIV / Mechanical Ventilation High-flow nasal cannula (HFNC), non-invasive ventilation (NIV), or invasive mechanical ventilation with systemic inflammation (CRP >=75 mg/L) • Dexamethasone 6 mg IV daily PLUS ; • Tocilizumab (IL-6 receptor antagonist; 8 mg/kg IV single dose, max 800 mg) OR Baricitinib (oral JAK-1/2 inhibitor; 4 mg PO daily for 14 days).
- 2. Tuberculosis ( Mycobacterium tuberculosis )
- Latent Tuberculosis Infection (LTBI) Screening & Diagnosis
Diagnostic Modalities:
Interferon-Gamma Release Assay (IGRA - QuantiFERON-TB Gold, T-SPOT.TB): Measures in vitro IFN-gamma release by sensitized T-cells exposed to M. tuberculosis -specific antigens (ESAT-6, CFP-10). Preferred in individuals with prior BCG (Bacille Calmette-Guérin) vaccination (eliminates false-positive cross-reactivity) and in patients unlikely to return for TST reading.
Tuberculin Skin Test (TST / PPD): Measures delayed-type hypersensitivity induration (measured in mm across the forearm at 48–72 hours).
TST Induration Cutoff Target Populations Considered Positive
>= 5 mm • HIV-infected individuals; • Recent close contacts of persons with active infectious tuberculosis; • Fibrotic/cavitary changes on chest radiograph consistent with prior inactive TB; • Solid organ transplant recipients and immunosuppressed patients (receiving >=15 mg/day prednisone equivalent for >=1 month or anti-TNF-alpha biologics)
>= 10 mm • Recent immigrants (<5 years) from high-prevalence countries (Asia, Africa, Latin America, Eastern Europe); • Injection drug users; • Residents and employees of high-risk congregate settings (prisons, nursing homes, homeless shelters, healthcare facilities); • Mycobacteriology laboratory personnel; • High-risk clinical conditions: Diabetes mellitus, chronic renal failure/hemodialysis, silicosis, gastrectomy, leukemia/lymphoma, head/neck cancer, body weight <90% ideal
- >= 15 mm • All persons with no known risk factors for tuberculosis (general population)
- Treatment of Latent Tuberculosis Infection (LTBI)
Rule out active pulmonary/extrapulmonary TB with symptom review and chest radiograph prior to initiating LTBI therapy. Preferred short-course rifamycin-based regimens are superior due to higher completion rates and lower hepatotoxicity:
3HP Regimen (Preferred): Once-weekly Isoniazid (900 mg) + Rifapentine (900 mg) for 3 months (12 doses total).
4R Regimen (Preferred): Daily Rifampin (600 mg daily) for 4 months .
3HR Regimen: Daily Isoniazid (300 mg) + Rifampin (600 mg) for 3 months .
6H / 9H Monotherapy (Alternative): Daily Isoniazid (300 mg daily) for 6 to 9 months plus Pyridoxine (Vitamin B6 25–50 mg daily).
Treatment of Active Tuberculosis
Active disease is treated with a two-phase regimen consisting of an initial 2-month Intensive Phase (RIPE) followed by a 4-month Continuation Phase (RI) (total 6 months). Active TB Regimen:
- Intensive Phase (Months 1–2): Rifampin + Isoniazid (with Pyridoxine) + Pyrazinamide + Ethambutol
- Continuation Phase (Months 3–6): Rifampin + Isoniazid (with Pyridoxine)
Drug Mechanism of Action Classic Adverse Effects Monitoring & Clinical Pearls
Rifampin (RIF) Inhibits DNA-dependent RNA polymerase • Orange-red discoloration of urine, sweat, tears, and contact lenses; • Potent CYP450 (CYP3A4) inducer (lowers levels of OCPs, warfarin, DOACs, methadone, protease inhibitors); • Hepatotoxicity, cholestasis, thrombocytopenia Baseline LFTs and CBC; counsel patient regarding harmless orange secretions and need for barrier contraception.
Isoniazid (INH) Inhibits mycolic acid synthesis • Peripheral neuropathy (due to pyridoxine deficiency); • Hepatotoxicity (toxic metabolite acetylhydrazine); • Drug-induced lupus (anti-histone antibodies) Co-prescribe Pyridoxine (Vitamin B6 25–50 mg daily) in all patients at risk for neuropathy (DM, pregnancy, alcoholism, renal failure, malnutrition). Discontinue INH if AST/ALT >3x ULN with symptoms, or >5x ULN without symptoms.
Pyrazinamide (PZA) Disrupts plasma membrane and energy metabolism • Hyperuricemia (causes non-gouty arthralgias and acute gout attacks); • Hepatotoxicity (most potent hepatotoxin among RIPE drugs) Avoid in severe liver disease; monitor uric acid if symptomatic gout develops. Can be omitted in pregnant women (extend continuation phase).
Ethambutol (EMB) Inhibits arabinosyl transferase (disrupts arabinogalactan cell wall) • Retrobulbar Optic Neuritis (decreased visual acuity, central scotoma, loss of red-green color discrimination ) Baseline and monthly testing of visual acuity (Snellen chart) and color discrimination (Ishihara plates) ; discontinue immediately if visual changes occur. Adjust dose in renal failure.