48.2 Sexually Transmitted Infections: Diagnosis, Staging & CDC Guidelines

ABFM Family Medicine Certification Study Guide Exam

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1 Chapter 1: Exam Structure, Blueprint & Clinical Decision-Making

1.1 Exam Blueprint, FMCLA vs. One-Day Exam & Board Scoring 1.2 Clinical Reasoning, Test-Taking Strategy & Ambiguity Management 1.3 Evidence-Based Medicine & Clinical Practice Guidelines in Primary Care

2 Chapter 2: Healthcare Systems, Practice Management & Quality

2.1 Practice Management, Billing, Coding & Documentation 2.2 Quality Improvement, Patient Safety & Diagnostic Stewardship 2.3 Interprofessional Team-Based Care & Care Coordination

3 Chapter 3: Ethics, Law, Biostatistics & Health Equity

3.1 Medical Ethics, Informed Consent & Surrogate Decision-Making 3.2 Biostatistics, Clinical Epidemiology & Diagnostic Test Interpretation 3.3 Social Determinants of Health, Health Equity & Cultural Humility 3.4 Physician Wellness, Burnout Prevention & Professionalism

4 Chapter 4: Lifestyle Counseling & Behavior Change

4.1 Alcohol Use Screening & Brief Intervention 4.2 Illicit Drug & Cannabis Counseling 4.3 Tobacco & Vaping Cessation Counseling

5 Chapter 5: Nutrition, Physical Activity & Chronic Disease Prevention

5.1 Dietary Counseling for Obesity & Chronic Disease Prevention 5.2 Exercise Prescription & Physical Activity Counseling 5.3 Genetic Risk Assessment & Family History Counseling

6 Chapter 6: Routine Adult Immunizations

6.1 ACIP Adult Respiratory Vaccines: Influenza, COVID-19, RSV & Pneumococcal 6.2 ACIP Adult Non-Respiratory Vaccines: Tdap, Shingrix, HPV & Hep B 6.3 Immunizations in Special Populations: Pregnancy, Asplenia & Immunocompromise

7 Chapter 7: Pediatric Health Maintenance & Surveillance

7.1 Newborn Examination & Early Postnatal Care 7.2 Well-Child Care, Developmental Surveillance & Milestones 7.3 Pediatric & Adolescent Screening: Vision, Hearing, Anemia & Lead 7.4 Pediatric Oral Health, Dental Screening & Fluoride

8 Chapter 8: Behavioral Health & Safety Screening

8.1 Primary Care Depression, Anxiety & Behavioral Health Screening 8.2 Domestic Violence, Intimate Partner Violence & Firearm Safety 8.3 Occupational Health & Recreational Safety Counseling

9 Chapter 9: Adult Preventive Screening: Cardiovascular & Metabolic

9.1 Cardiovascular Disease & Hypertension Screening 9.2 Type 2 Diabetes Screening & Prediabetes Risk Stratification 9.3 Abdominal Aortic Aneurysm & Osteoporosis Screening

10 Chapter 10: Adult Cancer Screening: Breast & Gynecologic

10.1 Breast Cancer Screening & Risk-Assessment 10.2 Cervical Cancer Screening & ASCCP Algorithms 10.3 Skin Cancer Clinical Assessment & Counseling

11 Chapter 11: Adult Cancer Screening: Colorectal, Lung & Prostate

11.1 Colorectal Cancer Screening Modalities & Intervals 11.2 Lung Cancer Screening with Low-Dose CT 11.3 Prostate Cancer Screening & Shared Decision-Making

12 Chapter 12: Sexual Health, Infectious Disease Screening & Contraception

12.1 Sexual Health Counseling & Risk-Reduction Strategies 12.2 STI Screening: Chlamydia, Gonorrhea, Syphilis & Trichomoniasis 12.3 Bloodborne Infectious Disease Screening: HIV & Hepatitis C

13 Chapter 13: Reproductive Life Planning, Lactation & Preoperative Care

13.1 Preconception Planning & Comprehensive Contraception Management 13.2 Lactation Support & Breastfeeding Counseling 13.3 Preoperative Medical Evaluation & Pre-Participation Sports Exam

14 Chapter 14: Emergent Cardiovascular Conditions

14.1 Acute Coronary Syndromes & Myocardial Infarction 14.2 Acute Chest Pain Risk Stratification & Triage 14.3 Acute or Critical Valvular Heart Emergencies

15 Chapter 15: Cardiac Arrhythmias, Heart Failure & Hypertensive Crises

15.1 Acute Atrial & Ventricular Arrhythmias 15.2 Acute Decompensated Heart Failure & Cardiogenic Shock 15.3 Hypertensive Emergency & Urgency Management

16 Chapter 16: Vascular & Thromboembolic Emergencies

16.1 Pulmonary Embolism & Deep Vein Thrombosis 16.2 Acute Aortic Syndromes & Peripheral Vascular Emergencies 16.3 Critical Limb Ischemia & Acute Arterial Occlusion

17 Chapter 17: Neurologic Emergencies: Stroke & Altered Consciousness

17.1 Acute Ischemic Stroke & Intracranial Hemorrhage 17.2 Syncope Evaluation & Status Epilepticus 17.3 Acute Delirium, Encephalopathy & Severe Confusion

18 Chapter 18: Neurologic Trauma & Acute Cranial Emergencies

18.1 Concussion, Moderate-to-Severe TBI & Intracranial Injury 18.2 Thunderclap & Acute Severe Secondary Headaches 18.3 Acute Ophthalmologic Emergencies

19 Chapter 19: Acute Abdominal, Pelvic & Gastrointestinal Emergencies

19.1 Acute Abdominal & Pelvic Pain Triage 19.2 Upper & Lower Gastrointestinal Bleeding 19.3 Acute Hepatic Failure, Cholangitis & Severe Jaundice

20 Chapter 20: Acute Pulmonary & Airway Emergencies

20.1 Acute Hypoxic Respiratory Failure & ARDS 20.2 Severe Community-Acquired Pneumonia & Empyema 20.3 Acute Severe Epistaxis & Airway Obstruction

21 Chapter 21: Acute Traumatic Injuries & Wound Care

21.1 Major Trauma Resuscitation & Initial Assessment 21.2 Burn Assessment, Inhalation Injury & Resuscitation 21.3 Laceration Management, Complex Wounds & Animal Bites

22 Chapter 22: Acute Orthopedic & Musculoskeletal Emergencies

22.1 Acute Ambulatory Fractures & Initial Splinting 22.2 Compartment Syndrome & Major Orthopedic Trauma 22.3 Septic Arthritis & Acute Microcrystalline Crises

23 Chapter 23: Severe Infections, Sepsis & Systemic Emergencies

23.1 Sepsis, Septic Shock & Initial Fluid Resuscitation 23.2 Necrotizing Soft Tissue Infections & Severe CNS Infections 23.3 Anaphylaxis Diagnosis, Epinephrine Dosing & Airway Protection

24 Chapter 24: Metabolic, Endocrine & Electrolyte Emergencies

24.1 Diabetic Ketoacidosis & Hyperosmolar Hyperglycemic State 24.2 Critical Electrolyte Emergencies: Dyskalemias & Dysnatremias 24.3 Severe Calcium Abnormalities & Acute Adrenal Crisis

25 Chapter 25: Hematologic, Urologic & Dental Emergencies

25.1 Severe Symptomatic Anemias & Coagulopathic Emergencies 25.2 Testicular Torsion, Priapism & Acute Urinary Retention 25.3 Urgent Odontogenic Infections & Dental Trauma

26 Chapter 26: Psychiatric, Behavioral & Obstetric/Gynecologic Emergencies

26.1 Suicidal Ideation, Acute Agitation & Behavioral Emergencies 26.2 Acute Physical & Sexual Assault Care 26.3 Life-Threatening Vaginal Bleeding & Ectopic Pregnancy 26.4 Environmental Heat Stroke & Severe Hypothermia

27 Chapter 27: Acute Head, Neck & Neurologic Symptoms

27.1 Primary Acute Headaches: Migraine, Tension & Cluster 27.2 Concussion & Minor Closed Head Injury Evaluation 27.3 Transient Ischemic Attack Evaluation & ABCD2 Risk Scoring

28 Chapter 28: Acute Cranial Nerves, Hearing & Sensory Symptoms

28.1 Peripheral Neuropathies: Bell's Palsy, Carpal Tunnel & Radiculopathy 28.2 Acute Tinnitus, Sudden Sensorineural Hearing Loss & Cerumen Impaction 28.3 Acute Dizziness, Benign Paroxysmal Positional Vertigo & Vestibular Neuritis

29 Chapter 29: Acute Upper Respiratory Tract Infections

29.1 Acute Viral Rhinosinusitis vs. Bacterial Rhinosinusitis 29.2 Acute Pharyngitis: Group A Streptococcus & Centor Criteria 29.3 Acute Otitis Media, Otitis Externa & Serous Effusion

30 Chapter 30: Acute Lower Respiratory Infections & Cough

30.1 Influenza, COVID-19 & Viral Respiratory Syndromes 30.2 Acute Bronchitis & Lower Respiratory Tract Infections 30.3 Ambulatory Community-Acquired Pneumonia

31 Chapter 31: Allergic, Nasal & Non-Infectious Pulmonary Conditions

31.1 Allergic Rhinitis & Acute Non-Anaphylactic Allergic Reactions 31.2 Acute Dyspnea in Ambulatory Care 31.3 Interstitial Lung Diseases & Sarcoidosis Presentation

32 Chapter 32: Acute Chest, Cardiac & Vascular Symptoms

32.1 Palpitations Evaluation & Arrhythmia Triage in Primary Care 32.2 Deep Vein Thrombosis & Superficial Thrombophlebitis 32.3 Ambulatory Hypotension & Orthostasis Evaluation

33 Chapter 33: Acute Upper Gastrointestinal Conditions

33.1 Peptic Ulcer Disease & Gastritis 33.2 Dysphagia, Esophagitis & Acute Esophageal Disorders 33.3 Acute Nausea, Vomiting & Foodborne Illness

34 Chapter 34: Acute Lower Gastrointestinal Conditions

34.1 Acute Infectious Diarrhea & Gastroenteritis 34.2 Acute Constipation & Functional Bowel Changes 34.3 Ano-Rectal Disorders: Hemorrhoids, Fissures, Abscesses & Pruritus Ani

35 Chapter 35: Inflammatory, Functional & Malabsorptive GI Disorders

35.1 Acute Flares of Inflammatory Bowel Disease 35.2 Irritable Bowel Syndrome: Diagnosis, Subtyping & Management 35.3 Celiac Disease & Malabsorption Syndromes

36 Chapter 36: Acute Abdominal, Hepatic & Biliary Disorders

36.1 Ambulatory Abdominal & Pelvic Pain Triage 36.2 Acute Cholecystitis, Biliary Colic & Pancreatitis 36.3 Acute Liver Injury & Viral Hepatitis

37 Chapter 37: Acute Abdominal Wall, Hernias & Dental Conditions

37.1 Abdominal Wall, Inguinal & Ventral Hernias 37.2 Acute Dental Pain, Odontogenic Abscess & Aphthous Ulcers 37.3 Acute Edema: Unilateral vs. Bilateral Diagnostic Evaluation

38 Chapter 38: Acute Infectious Dermatoses

38.1 Bacterial Skin Infections: Impetigo, Cellulitis & Cutaneous Abscesses 38.2 Fungal Skin Infections: Tinea Corporis, Cruris, Pedis & Onychomycosis 38.3 Viral Cutaneous Infections: Herpes Simplex, Zoster & Molluscum Contagiosum

39 Chapter 39: Inflammatory, Allergic & Autoimmune Dermatoses

39.1 Atopic Dermatitis, Contact Dermatitis & Eczematous Flares 39.2 Non-Infectious Rashes: Urticaria, Drug Eruptions & Erythema Multiforme 39.3 Cutaneous Malignancies & Premalignant Lesions: AK, BCC, SCC & Melanoma

40 Chapter 40: Acute Shoulder, Elbow & Upper Extremity Injuries

40.1 Rotator Cuff Pathology, Tendinopathy & Shoulder Impingement 40.2 Lateral & Medial Epicondylitis, Olecranon Bursitis & Elbow Sprains 40.3 Wrist & Hand Soft-Tissue Injuries: De Quervain, TFCC & Finger Sprains

41 Chapter 41: Acute Knee, Ankle & Lower Extremity Injuries

41.1 Meniscal Tears, Ligamentous Knee Injuries & Patellofemoral Pain 41.2 Ankle Sprains, Ottawa Ankle Rules & Achilles Tendinopathy 41.3 Plantar Fasciitis, Shin Splints & Overuse Syndromes

42 Chapter 42: Acute Ambulatory Fractures & Dislocations

42.1 Distal Radius, Scaphoid & Common Upper Extremity Fractures 42.2 Metatarsal, Clavicle & Common Lower Extremity Fractures 42.3 Joint Dislocation Management: Nursemaid's Elbow & Shoulder Subluxation

43 Chapter 43: Acute Axial Musculoskeletal Pain & Falls

43.1 Acute Low Back Pain: Red Flags, Strain & Disc Herniation 43.2 Acute Cervical Strain, Whiplash & Axial Neck Pain 43.3 Evaluation of Falls in Ambulatory & Older Patients

44 Chapter 44: Acute Inflammatory Arthropathies & Generalized Pain

44.1 Acute Inflammatory Arthritis & Spondyloarthropathies 44.2 Myalgias, Rhabdomyolysis & Post-Viral Pain Syndromes 44.3 Acute Non-Headache Pain Management Strategies

45 Chapter 45: Acute Renal, Urinary & Genitourinary Conditions

45.1 Uncomplicated UTI, Pyelonephritis & Acute Urethritis 45.2 Hematuria Workup & Glomerulonephritis 45.3 Nephrolithiasis & Acute Urinary Tract Obstruction

46 Chapter 46: Acute Male Genitourinary & Prostatic Conditions

46.1 Acute Prostatitis, Epididymitis & Orchitis 46.2 Acute Scrotal Pain: Torsion vs Appendage, BPH & Male Genital Emergencies 46.3 Acute Urinary Retention & Incontinence Evaluation

47 Chapter 47: Acute Women's Health & Early Pregnancy Care

47.1 Early Pregnancy Diagnosis, Dating & Initial Complications 47.2 Abnormal Uterine Bleeding & Acute Menstrual Disorders 47.3 Premenstrual Syndrome & Premenstrual Dysphoric Disorder

48 Chapter 48: Breast Disorders, STIs & Pediatric Elimination

48.1 Palpable Breast Mass, Mastitis & Nipple Discharge 48.2 Sexually Transmitted Infections: Diagnosis, Staging & CDC Guidelines 48.3 Pediatric Enuresis & Encopresis

49 Chapter 49: Systemic Signs, Metabolic Dysregulation & Miscellaneous Infections

49.1 Acute Fever, Sepsis Screening & FUO in Primary Care 49.2 Acute Hyperglycemia & Symptomatic Hypoglycemia 49.3 Electrolyte Abnormalities: Mild-to-Moderate Disturbances 49.4 Vector-Borne, Tick-Borne & Rickettsial Illnesses

50 Chapter 50: Chronic Cardiovascular Diseases: Hypertension & Ischemia

50.1 Essential Hypertension Management: 2025 AHA/ACC Guideline & JNC Strategies 50.2 Chronic Coronary Artery Disease & Post-MI Secondary Prevention 50.3 Chronic Heart Failure: HFrEF, HFpEF & Quadruple GDMT

51 Chapter 51: Chronic Vascular, Valvular & Dyslipidemic Diseases

51.1 Peripheral Arterial Disease & Claudication 51.2 Chronic Valvular Heart Disease & Murmur Evaluation 51.3 Lipid Disorders & ASCVD Risk-Based Statin Therapy

52 Chapter 52: Chronic Respiratory Diseases: Asthma & COPD

52.1 Chronic Asthma Management: GINA Stepwise SMART Therapy 52.2 Chronic Obstructive Pulmonary Disease: GOLD Recommendations 52.3 Solitary Pulmonary Nodule Evaluation & Fleischner Society Criteria

53 Chapter 53: Chronic Metabolic Diseases: Diabetes Mellitus

53.1 Type 2 Diabetes Management: ADA Pharmacotherapy Algorithms 53.2 Type 1 Diabetes: Basal-Bolus Insulin, CGMs & Diabetic Complications 53.3 Diabetic Microvascular & Macrovascular Disease Surveillance

54 Chapter 54: Obesity, Nutrition & Metabolic Bone Diseases

54.1 Medical & Behavioral Management of Obesity & Incretin Mimetics 54.2 Osteoporosis & Metabolic Bone Disease: DEXA, FRAX & Antiresorptives 54.3 Nutritional Deficiencies: Vitamin D, B12, Iron & Malnutrition

55 Chapter 55: Chronic Endocrine Disorders

55.1 Primary & Subclinical Hypothyroidism, Hyperthyroidism & Nodules 55.2 Adrenal Disorders: Addison's Disease & Cushing's Syndrome 55.3 Hypercalcemia, Hyperparathyroidism & Pituitary Disorders

56 Chapter 56: Chronic Kidney Disease & Venous Disorders

56.1 Chronic Kidney Disease: KDIGO Staging & Renoprotective Therapy 56.2 Chronic Venous Insufficiency, Stasis Dermatitis & Lymphedema 56.3 Chronic Electrolyte & Acid-Base Management in CKD

57 Chapter 57: Chronic Gastrointestinal & Hepatic Diseases

57.1 Gastroesophageal Reflux Disease, Barrett's Esophagus & Dyspepsia 57.2 Chronic Liver Disease: MASLD/NAFLD, Cirrhosis & Portal Hypertension 57.3 Viral Hepatitis B & C: Long-Term Monitoring & DAA Therapy

58 Chapter 58: Colorectal Surveillance & Chronic Pancreaticobiliary Care

58.1 Post-Polypectomy Colorectal Polyp Surveillance Guidelines 58.2 Chronic Pancreatitis & Exocrine Pancreatic Insufficiency 58.3 Chronic Nausea, Gastroparesis & Functional GI Disorders

59 Chapter 59: Chronic Musculoskeletal & Rheumatologic Disorders

59.1 Osteoarthritis: Hip, Knee & Hand Management 59.2 Spinal Conditions: Spinal Stenosis, Spondylolisthesis & Compression Fractures 59.3 Chronic Myopathies & Fibromyalgia Syndrome

60 Chapter 60: Chronic Neurologic & Neurodegenerative Disorders

60.1 Dementia: Alzheimer's, Vascular & Lewy Body Disease 60.2 Parkinson's Disease & Essential Tremor 60.3 Epilepsy: Chronic Antiseizure Medications & Post-Stroke Care

61 Chapter 61: Chronic Peripheral Nerves, Pain & Sensory Disorders

61.1 Diabetic & Chronic Peripheral Neuropathies 61.2 Chronic Pain Syndromes & Chronic Daily Headaches 61.3 Chronic Tinnitus, Presbycusis & Persistent Dizziness

62 Chapter 62: Chronic Psychiatric Disorders

62.1 Major Depressive Disorder & Generalized Anxiety Disorder 62.2 Bipolar Disorder: Maintenance Pharmacotherapy & Lithium Monitoring 62.3 Adult & Pediatric Attention-Deficit/Hyperactivity Disorder

63 Chapter 63: Chronic Behavioral Health & Neurodevelopmental Conditions

63.1 Chronic Behavioral Conditions: PTSD, OCD & Somatization 63.2 Autism Spectrum Disorder & Intellectual Disabilities 63.3 Eating Disorders: Anorexia Nervosa, Bulimia & Binge Eating

64 Chapter 64: Chronic Substance Use Disorders & Tobacco Cessation

64.1 Alcohol Use Disorder: Pharmacotherapy & Relapse Prevention 64.2 Opioid & Stimulant Use Disorders: MOUD & Harm Reduction 64.3 Longitudinal Tobacco Cessation Pharmacotherapy

65 Chapter 65: Chronic Dermatologic Conditions

65.1 Acne Vulgaris, Rosacea & Seborrheic Dermatitis 65.2 Chronic Plaque Psoriasis & Biologic Therapies 65.3 Chronic Eczema, Hidradenitis Suppurativa & Cutaneous Lupus

66 Chapter 66: Chronic Reproductive, Infectious & Geriatric Special Care

66.1 Chronic Menstrual Disorders, Infertility & Sexual Dysfunction 66.2 Menopause Management & Hormone Replacement Therapy 66.3 Chronic HIV Infection Management & Primary Care Integration 66.4 Gender-Affirming Primary Care & Hormone Therapy 66.5 Advance Care Planning, Palliative Care & End-of-Life Symptom Control

67 Chapter 67: Continuity Care: Sleep, Fatigue, Cancer, Pregnancy & the Adult Preventive Visit

67.1 Chronic Insomnia & Obstructive Sleep Apnea 67.2 Chronic Malaise, Fatigue & ME/CFS 67.3 Primary Care During Cancer Treatment & Survivorship 67.4 Routine Prenatal Care & Longitudinal Pregnancy Management 67.5 The Periodic Adult Health Examination & Medicare Annual Wellness Visit

48.2 Sexually Transmitted Infections: Diagnosis, Staging & CDC Guidelines

Key Takeaways Explain This Topic AI

Under the CDC STI Treatment Guidelines, uncomplicated urogenital, anorectal, or pharyngeal Neisseria gonorrhoeae infection is treated with Ceftriaxone 500 mg IM in a single dose for patients weighing <150 kg (1,000 mg IM if >=150 kg); oral azithromycin is NO LONGER recommended for gonorrhea treatment due to antimicrobial stewardship and resistance concerns.

For Chlamydia trachomatis urogenital or rectal infection, oral Doxycycline 100 mg twice daily for 7 days is the definitive first-line regimen, demonstrating significantly higher microbiologic cure rates than single-dose azithromycin (particularly for rectal chlamydia); Azithromycin 1 g orally single dose is reserved strictly for pregnancy or documented severe non-adherence.

Primary, secondary, and early latent syphilis (<1 year duration) are treated with a single dose of intramuscular Benzathine penicillin G 2.4 million units; late latent syphilis, latent of unknown duration, and tertiary cardiovascular syphilis require Benzathine penicillin G 2.4 million units IM once weekly for 3 consecutive weeks (total 7.2 million units).

Neurosyphilis, ocular syphilis, and otosyphilis can develop at ANY stage of infection and require intravenous Aqueous crystalline penicillin G 18 to 24 million units daily (administered as 3 to 4 million units IV every 4 hours or continuous infusion) for 10 to 14 days.

The Jarisch-Herxheimer reaction is an acute, self-limiting febrile systemic reaction occurring within 2 to 24 hours of starting penicillin therapy for syphilis, caused by massive treponemal lysis releasing inflammatory cytokines; it requires antipyretics and supportive hydration and must NOT be mistaken for an allergic drug reaction.

Last updated: September 2026

Neisseria gonorrhoeae: Clinical Staging, Diagnosis & Updated CDC Guidelines

Neisseria gonorrhoeae is a fastidious, Gram-negative, intracellular coffee-bean-shaped diplococcus that infects mucosal columnar and transitional epithelium. Widespread emergence of multidrug-resistant strains has made gonococcal infection a premier public health concern, driving major updates in CDC treatment guidelines.

Clinical Manifestations

Urogenital Infection :

Men : Acute anterior urethritis characterized by copious, frankly purulent, yellow-green urethral discharge and severe burning dysuria. Incubation is 1 to 14 days. Over 90% of men are highly symptomatic, prompting rapid medical attention. Untreated infection can ascend to cause acute epididymo-orchitis or seminal vesiculitis.

Women : Endocervical infection is the primary site, but up to 50% to 70% of women are asymptomatic or experience mild non-specific symptoms (mucopurulent cervical discharge, intermenstrual vaginal bleeding, dyspareunia, dysuria). Ascending infection produces acute Pelvic Inflammatory Disease (PID) , tubal scarring, ectopic pregnancy, and involuntary infertility.

Extragenital Infections :

Anorectal Gonorrhea : Frequently asymptomatic; may present with proctitis, rectal tenesmus, purulent discharge, rectal bleeding, and pruritus ani.

Pharyngeal Gonorrhea : Acquired via receptive oral sex. Overwhelmingly asymptomatic (>90%), creating a massive silent anatomic reservoir for transmission. Highly resistant to eradication.

Gonococcal Conjunctivitis : Marked conjunctival injection and copious purulent ocular drainage. In neonates (ophthalmia neonatorum), acquired during delivery through an infected birth canal; can rapidly cause corneal ulceration and permanent blindness.

Disseminated Gonococcal Infection (DGI) : Occurs in 0.5% to 3% of patients via hematogenous spread from mucosal sites, classically in patients with terminal complement deficiencies (C5-C9). Presents as:

Tenosynovitis-Dermatitis-Polyarthralgia Syndrome : Triad of migratory polyarthralgias, acute tenosynovitis (wrist, fingers, ankles), and painless pustular, petechial, or necrotic skin lesions with an erythematous halo concentrated on the distal extremities.

Purulent Septic Arthritis : Acute monoarthritis or oligoarthritis (predominantly knee, wrist, or ankle) with large purulent synovial effusions.

Diagnostic Testing Protocols for Gonorrhea

Nucleic Acid Amplification Testing (NAAT) : The undisputed gold standard for diagnostic sensitivity (>95%) and specificity (>99%).

Men : First-catch urine (first 20-30 mL of the urinary stream, without prior cleaning of the meatus; patient should not have voided for at least 1-2 hours) or intraurethral swab.

Women : Patient-collected or clinician-collected vaginal swab is the preferred specimen, possessing superior sensitivity to endocervical swabs and urine testing.

Extragenital NAAT Testing : Mandatory rectal and pharyngeal swab NAAT for any individual reporting receptive anal or oral sexual exposure within the preceding 12 months. Routine urogenital testing misses up to 70% of extragenital gonococcal infections!

Gram Stain Microscopy : High sensitivity (>95%) in symptomatic men displaying Gram-negative intracellular diplococci within polymorphonuclear leukocytes. However, Gram stain of endocervical swabs has unacceptably low sensitivity (<40-50%) in women due to normal commensal vaginal flora and cannot exclude infection.

Bacterial Culture : Performed on selective media (modified Thayer-Martin). Indicated when treatment failure is suspected, enabling phenotypic antimicrobial susceptibility testing.

Updated CDC Antimicrobial Treatment Guidelines CDC GUIDELINES: NEISSERIA GONORRHOEAE TREATMENT

• Clinical Scenario Patient Body Weight First-Line Antimicrobial Regimen
• ════════════════════════════════════════════════════════════════════════════════════════════════
• Uncomplicated Urogenital, < 150 kg (330 lbs) Ceftriaxone 500 mg IM in a single dose
• Anorectal, or Pharyngeal ────────────────────────────────────────────────────────────────────
• Gonococcal Infection >= 150 kg (330 lbs) Ceftriaxone 1,000 mg (1 g) IM in a single dose

Co-Infection Status: If Chlamydia trachomatis has NOT been definitively excluded:

• ADD Doxycycline 100 mg PO BID x 7 days
• (If chlamydia is excluded by NAAT, Ceftriaxone monotherapy is sufficient)

• Severe Cephalosporin Any Weight Gentamicin 240 mg IM single dose
• Anaphylaxis / Allergy PLUS Azithromycin 2 g PO in a single dose
• ════════════════════════════════════════════════════════════════════════════════════════════════

Important

THE PARADIGM SHIFT: AZITHROMYCIN IS NO LONGER RECOMMENDED Under prior CDC guidelines, gonorrhea was routinely treated with "dual therapy" consisting of ceftriaxone plus oral azithromycin 1 g. Dual therapy with azithromycin is NO LONGER RECOMMENDED.

The CDC removed azithromycin due to rapid worldwide escalation of macrolide resistance in N. gonorrhoeae and to preserve macrolide utility for other respiratory and systemic infections. Today, the standard is high-dose intramuscular Ceftriaxone monotherapy (500 mg IM) , provided concurrent chlamydial infection has been ruled out.

Chlamydia trachomatis: Pathophysiology & Management

Chlamydia trachomatis is an obligate intracellular bacterium that exists in two distinct cellular forms: the infectious, metabolically inert elementary body (EB) that survives extracellularly, and the non-infectious, metabolically active reticulate body (RB) that replicates within host cell cytoplasmic inclusions.

Serovars & Clinical Spectrum

Serovars D through K : Cause urogenital chlamydial infections, inclusion conjunctivitis, and neonatal pneumonia.

Serovars L1, L2, L3 : Cause Lymphogranuloma Venereum (LGV) , an invasive STI presenting with a transient painless genital papule/ulcer followed by aggressive painful inguinal lymphadenitis ("groove sign" separating inguinal and femoral nodes by Poupart's ligament) and severe hemorrhagic proctitis in men who have sex with men (MSM). LGV requires extended oral Doxycycline 100 mg BID for a full 21 days .

Clinical Presentation & Long-Term Sequelae

The "Silent" Epidemic : Chlamydia is the most frequently reported bacterial infectious disease in the United States. Over 70% to 80% of infected women and 50% of infected men are entirely asymptomatic .

When symptomatic, it produces mild dysuria, scant clear or mucoid urethral discharge, or cervical friability with postcoital spotting.

Long-Term Female Complications :

Pelvic Inflammatory Disease (PID) : Subclinical or overt ascending infection of the endometrium, fallopian tubes, and ovaries.

Tubal Factor Infertility & Ectopic Pregnancy : Each episode of PID increases the risk of irreversible tubal occlusion and subsequent ectopic gestation exponentially (approximate 8% risk after 1 episode, 20% after 2, and >40% after 3 episodes).

Fitz-Hugh-Curtis Syndrome (Perihepatitis) : Transperitoneal or hematogenous spread causing inflammation of the hepatic capsule. Characterized by severe pleuritic right upper quadrant pain, elevated serum transaminases, and laparoscopically pathognomonic "violin-string" fibrous adhesions between the liver surface and anterior abdominal wall.

Reactive Arthritis : HLA-B27-associated post-infectious triad of urethritis, uveitis/conjunctivitis, and asymmetric oligoarthritis ("can't see, can't pee, can't climb a tree"), frequently accompanied by circinate balanitis and keratoderma blennorrhagica.

First-Line Antimicrobial Therapy CDC GUIDELINES: CHLAMYDIA TRACHOMATIS REGIMENS

• Patient Category First-Line Guideline Regimen Alternative Regimen
• ══════════════════════════════════════════════════════════════════════════════════════════════
• Non-Pregnant Adults Doxycycline 100 mg PO BID x 7 days Azithromycin 1 g PO single dose
• and Adolescents (Gold Standard First-Line) OR Levofloxacin 500 mg PO daily x 7d

• Pregnant Patients Azithromycin 1 g PO in a single dose Amoxicillin 500 mg PO TID x 7 days
• (Doxycycline CONTRAINDICATED)
• ══════════════════════════════════════════════════════════════════════════════════════════════

Why Doxycycline Surpassed Azithromycin : Randomized clinical trials demonstrated that oral Doxycycline achieves a >95% to 98% cure rate for urogenital and anorectal chlamydia. Single-dose Azithromycin achieves comparable cure rates (>95%) for urogenital infections but is substantially inferior for rectal chlamydial infection (microbiologic cure rate only 70% to 80%) . Because asymptomatic rectal co-infection is common across all demographics, Doxycycline 100 mg BID for 7 days is the definitive first-line standard .

Test of Cure (TOC) : Routine TOC is NOT recommended for non-pregnant patients treated with first-line regimens unless compliance is questionable, symptoms persist, or reinfection is suspected. However, TOC is MANDATORY in pregnancy (perform NAAT 4 weeks after completing treatment).

Re-screening Mandate : All patients treated for chlamydia (or gonorrhea) must be rescreened 3 months post-treatment due to high rates of reinfection from untreated partners.

Syphilis: Treponema pallidum Staging, Clinical Manifestations & Neurosyphilis

Syphilis is a chronic systemic infection caused by the spirochete Treponema pallidum subspecies pallidum . Because it can mimic almost any clinical pathology, it is historically known as "The Great Imitator."

Clinical Staging & Manifestations CLINICAL STAGING OF TREPONEMA PALLIDUM

• Clinical Stage Incubation & Timing Cardinal Clinical Features
• ═══════════════════════════════════════════════════════════════════════════════════════════════════
• Primary Syphilis 10 to 90 days Solitary, painless chancre with an indurated
• (average 21 days) base and clean, non-purulent crater; bilateral
• painless regional lymphadenopathy; heals in 3-6 weeks

• Secondary Syphilis 2 to 8 weeks after Disseminated bacteremic phase: diffuse non-pruritic
• chancre resolution maculopapular rash involving the PALMS and SOLES;
• (up to 6 months) condylomata lata (moist verrucous plaques in perineum);
• mucous patches; epitrochlear lymphadenopathy; fever

• Early Latent Syphilis Infection acquired within Completely asymptomatic; seroreactive non-treponemal
• preceding 12 months and treponemal tests; potentially infectious

• Late Latent Syphilis Infection acquired >=12 mo Completely asymptomatic; seroreactive; low infectious
• / Unknown Duration prior or unknown duration risk except vertical maternal-fetal transmission

• Tertiary Syphilis 1 to 30+ years after Granulomatous gummas (skin, bones, liver);
• initial untreated infection Cardiovascular syphilis (ascending thoracic aortic
• aneurysm, aortic regurgitation, coronary stenosis)
• ═══════════════════════════════════════════════════════════════════════════════════════════════════
• Primary Syphilis

The hallmark lesion is the chancre : an ulcer that begins as a single painless papule that rapidly erodes into a clean-based, punched-out crater with raised, cartilaginous, indurated borders .

Painless bilateral inguinal lymphadenopathy accompanies the chancre.

The chancre heals spontaneously within 3 to 6 weeks without scarring, often giving the patient false reassurance that the disease has resolved.

Secondary Syphilis

Manifests secondary to widespread vascular dissemination of spirochetes throughout tissues.

Cutaneous Eruption : Bilateral, symmetric, non-pruritic copper-red or pink maculopapular eruption. Crucially involves the palms of the hands and soles of the feet (a key board-exam differentiator alongside erythema multiforme, Rocky Mountain spotted fever, and Coxsackievirus A16).

Condylomata Lata : Highly infectious, hypertrophic, flat, moist, broad-based verrucous plaques that flourish in warm, intertriginous skin folds (perineum, vulva, scrotum, perianal region). (Do not confuse with HPV condylomata acuminata, which are dry, pedunculated, cauliflowered warts).

Mucous Patches : Superficial, painless, grayish-white silvery erosions on the buccal mucosa, tongue, or lips, teeming with spirochetes.

Lymphadenopathy : Generalized non-tender lymphadenopathy. Palpable epitrochlear lymphadenopathy is highly specific for secondary syphilis.

Neurosyphilis, Ocular Syphilis & Otosyphilis

Caution

NEUROSYPHILIS CAN OCCUR AT ANY CLINICAL STAGE Central nervous system invasion by Treponema pallidum can occur within days of initial primary infection and does NOT require decades to manifest.

Early Neurosyphilis : Manifests months to years after infection as acute syphilitic meningitis (cranial nerve palsies, particularly CN VII and VIII) or meningovascular syphilis (ischemic stroke syndrome in a young individual caused by endarteritis of middle cerebral artery branches).

Late Neurosyphilis : Manifests decades later:

Tabes Dorsalis : Slow progressive demyelination and degeneration of the spinal cord posterior columns and dorsal roots. Clinical tetrad: sensory ataxia (positive Romberg test, stomping wide-based gait), loss of proprioception and vibratory sensation, "lightning" lancinating pains in the lower extremities, and neurogenic Charcot joints.

General Paresis : Chronic progressive dementia, personality disintegration, grandiose delusions, tremors, and dysarthria.

Argyll Robertson Pupil : Pathognomonic bilateral small, irregular pupils that exhibit light-near dissociation : pupils briskly constrict during visual accommodation for near objects, but DO NOT react to direct light stimulation ("Prostitute's Pupil: Accommodates but does not React").

Ocular and Otic Syphilis : Posterior uveitis, panuveitis, optic neuropathy, sensorineural hearing loss, and vestibular vertigo. Any syphilitic patient with ocular or auditory symptoms must be staged and managed identically to neurosyphilis!

Diagnostic Algorithms & CDC Staging Treatment

Serodiagnosis requires two distinct classes of tests: non-treponemal and treponemal . SEROLOGIC TESTING COMPARISON FOR SYPHILIS

• Test Category Specific Assays Clinical Role & Interpretation
• ═════════════════════════════════════════════════════════════════════════════════════════════════
• Non-Treponemal Tests RPR (Rapid Plasma Reagin) Detects antibodies to cardiolipin-cholesterol-
• VDRL (Venereal Disease lecithin antigens. QUANTITATIVE titer reflects

Research Laboratory) disease activity and monitors treatment success.

Becomes non-reactive or serofast with time.

Treponemal Tests TP-PA (T. pallidum Particle) Detects specific antibodies directed against

FTA-ABS (Fluorescent Absorbed) Treponema pallidum antigens. QUALITATIVE only.

EIA / CIA (Enzyme Immunoassay) Remains POSITIVE FOR LIFE (cannot monitor cure).

• ═════════════════════════════════════════════════════════════════════════════════════════════════
• Traditional vs. Reverse Sequence Algorithms

Traditional Algorithm : Screen with a quantitative non-treponemal test (RPR). If non-reactive, report negative. If reactive, confirm specificity with a treponemal assay (TP-PA). If both are reactive, syphilis is diagnosed.

Reverse Sequence Algorithm : Increasingly adopted by modern automated clinical laboratories. Initial screening begins with an automated treponemal test ( EIA or CIA ):

If EIA/CIA is reactive, the laboratory reflexively tests the sample with a quantitative non-treponemal test ( RPR ):

If RPR is reactive: Confirms active untreated syphilis (or recently treated infection with residual titer).

If RPR is non-reactive (discordant): Perform a second, distinct treponemal assay (TP-PA) :

If second treponemal test (TP-PA) is reactive: Represents either previously successfully treated syphilis or untreated late latent syphilis .

If second treponemal test (TP-PA) is non-reactive: The initial screening EIA was a biological false positive .

Monitoring Treatment Success: The Fourfold Titer Drop

Non-treponemal titers (RPR or VDRL) are used to document curative response:

A fourfold decline in titer (equivalent to a two-dilution drop ) confirms adequate therapeutic response.

Example: A pre-treatment RPR of 1:32 dropping to 1:8 (or 1:64 dropping to 1:16) represents a fourfold decline.

Titers should be followed at 6 and 12 months post-treatment in primary/secondary syphilis, and at 6, 12, and 24 months in latent syphilis.

CDC Guideline Antimicrobial Regimens CDC GUIDELINES: SYPHILIS TREATMENT REGIMENS

• Syphilis Clinical Stage First-Line Recommended Antimicrobial Regimen
• ═══════════════════════════════════════════════════════════════════════════════════════════════════
• Primary, Secondary, or Benzathine Penicillin G 2.4 million units IM in a
• Early Latent Syphilis (< 1 year) SINGLE DOSE (Administered as 1.2 million units in each buttock)

• Late Latent, Latent of Unknown Benzathine Penicillin G 2.4 million units IM
• Duration, or Tertiary Syphilis ONCE WEEKLY FOR 3 CONSECUTIVE WEEKS (Total 7.2 million units)

• Neurosyphilis, Ocular Syphilis, Aqueous Crystalline Penicillin G 18 to 24 million units IV
• or Otic Syphilis daily, administered as 3 to 4 million units IV every 4 hours
• (or continuous IV infusion) for 10 to 14 DAYS
• ═══════════════════════════════════════════════════════════════════════════════════════════════════

Caution

CRITICAL PREGNANCY MANDATE: PENICILLIN IS THE ONLY ACCEPTABLE DRUG In pregnant patients, Parenteral Benzathine Penicillin G is the ONLY curative treatment that reliably prevents maternal-fetal spirochetal transmission and congenital syphilis.

Doxycycline and tetracyclines are strictly contraindicated in pregnancy due to permanent fetal tooth discoloration and bone growth inhibition. Erythromycin and azithromycin do NOT cross the placental barrier in sufficient concentrations to treat the fetus. Therefore, any pregnant woman with syphilis and a documented true penicillin allergy MUST BE ADMITTED FOR INPATIENT PENICILLIN DESENSITIZATION followed immediately by the appropriate Benzathine Penicillin G regimen.

• The Jarisch-Herxheimer Reaction & Expedited Partner Therapy
• The Jarisch-Herxheimer Reaction

Pathophysiology : An acute, systemic inflammatory reaction provoked by the rapid bactericidal destruction and lysis of massive numbers of spirochetes upon initiating penicillin therapy. Lysis releases large quantities of treponemal endotoxin-like outer membrane lipoproteins into the circulation, stimulating macrophages to release a surge of pro-inflammatory cytokines: Tumor Necrosis Factor-alpha (TNF-alpha), Interleukin-6 (IL-6), and Interleukin-8 (IL-8) .

Incidence & Timing : Most commonly observed in patients with high bacterial burdens (seen in 50% to 75% of patients treated for secondary syphilis , 30% with primary syphilis). Symptoms begin abruptly within 2 to 24 hours following the first penicillin injection.

Clinical Manifestations : Shaking chills, high fevers, diaphoresis, headache, generalized myalgias, tachycardia, transient hypotension, and a transient accentuation and erythema of the syphilitic skin rash.

Clinical Management & Distinction from Penicillin Allergy :

The Jarisch-Herxheimer reaction is benign and self-limiting , resolving spontaneously within 12 to 24 hours.

Management is purely supportive: antipyretics (acetaminophen 650-1000 mg PO every 6 hours or ibuprofen 600 mg PO every 8 hours), oral or intravenous hydration, and bed rest.

CRITICAL DISTINCTION : It is NOT an IgE-mediated penicillin allergy (no urticarial wheals, bronchospasm, angioedema, or anaphylaxis). Penicillin therapy MUST NOT be discontinued, and the patient should NOT be labeled as penicillin-allergic.

Pregnancy Warning : In pregnant women, the intense cytokine surge can induce transient uterine contractions, non-reassuring fetal heart rate decelerations, or preterm labor; pregnant women with secondary syphilis should be monitored in a setting equipped for fetal monitoring.

Expedited Partner Therapy (EPT)

Expedited Partner Therapy (EPT) is the evidence-based clinical practice of treating the sexual partners of patients diagnosed with an STI by providing prescriptions or medications directly to the index patient to deliver to their partners, without requiring the healthcare provider to examine the partner first .

Epidemiologic Rationale : Reinfection rates from untreated baseline partners reach 20% to 30% within 3 months. Traditional partner notification (advising patients to tell partners to seek care) fails in >50% of cases.

Legal Standing & Practice : EPT is legally permissible in almost all 50 US states for heterosexually transmitted Chlamydia trachomatis and Neisseria gonorrhoeae .

For chlamydia: Index patient is provided an extra prescription for oral Doxycycline 100 mg BID for 7 days (or oral Azithromycin 1 g single dose if adherence is questionable) accompanied by educational brochures warning of allergy, pregnancy, and instructing sexual abstinence until 7 days post-treatment.

For gonorrhea: EPT is more complex because first-line therapy requires intramuscular ceftriaxone. If an in-person partner clinic visit cannot be achieved, CDC guidelines permit oral Cefixime 800 mg PO in a single dose delivered to the partner via EPT.

Lookback Interval : All sexual contacts within the preceding 60 days must be evaluated and treated.

Loading diagram... CDC Syphilis Diagnostic Algorithm and Staged Antimicrobial Selection