Viral Conjunctivitis

1. Topic Overview (Clinical Overview)

Summary

Viral Conjunctivitis is an acute inflammation of the conjunctiva caused by viral infection, representing the most common infectious cause of the red eye. [1] Adenovirus accounts for approximately 65-90% of all viral conjunctivitis cases, making it the predominant pathogen. [2] The condition is characterized by a watery (serous) discharge, diffuse conjunctival injection, follicular conjunctival reaction, and frequently preauricular lymphadenopathy. [3]

The disease is highly contagious, spreading through direct contact with infected ocular secretions and contaminated fomites (towels, pillowcases, ophthalmic equipment). [4] Most cases follow a self-limiting course, with symptom resolution within 2-3 weeks, though corneal subepithelial infiltrates in epidemic keratoconjunctivitis (EKC) may persist for months. [5] The cornerstone of management is supportive care with lubricating drops and stringent hygiene measures to prevent transmission. [6]

Critical to management is the exclusion of sight-threatening mimics, particularly Herpes Simplex Virus (HSV) keratitis, which presents with corneal dendritic ulceration and requires antiviral therapy. [7] Inappropriate steroid use in unrecognized HSV keratitis can lead to corneal perforation and permanent visual loss. [8]

Key Facts

• Epidemiology: Accounts for 80% of acute infectious conjunctivitis; extremely common in primary care and emergency settings. [1,2]
• Primary Pathogen: Adenovirus (65-90% of cases); serotypes 3, 4, 7 (pharyngoconjunctival fever), 8, 19, 37 (epidemic keratoconjunctivitis). [2,9]
• Transmission: Highly contagious; direct contact, respiratory droplets, fomites; healthcare-associated outbreaks common. [4,10]
• Classic Triad: Watery discharge + Follicular conjunctivitis + Preauricular lymphadenopathy. [3]
• Course: Symptoms worsen days 3-5, peak at 1 week, resolve over 2-3 weeks; subepithelial infiltrates may persist months in EKC. [5]
• Management: Supportive only (lubricants, cold compresses, hygiene); antibiotics not indicated; steroids contraindicated unless HSV excluded. [6,11]
• Key Differential: HSV keratitis (dendritic ulcer on fluorescein staining) requires antiviral therapy. [7]

Clinical Pearls

"Watery = Viral, Purulent = Bacterial, Itchy = Allergic": The character of discharge is the most useful clinical discriminator. Watery/serous discharge indicates viral etiology; thick yellow-green purulent discharge suggests bacterial infection; clear discharge with intense itching indicates allergic conjunctivitis. [3,12]

"Preauricular Lymph Nodes Are the Key": Tender, palpable preauricular lymphadenopathy is highly specific for adenoviral conjunctivitis and rarely seen in bacterial or allergic etiologies. The conjunctiva drains to preauricular and submandibular nodes; robust lymphocytic response characterizes viral infection. [3]

"ALWAYS Exclude HSV Before Steroids": Unilateral presentation, vesicular periocular rash, severe photophobia, or recurrent episodes should raise suspicion for HSV keratitis. Fluorescein staining must be performed to exclude dendritic ulceration. Corticosteroids in HSV keratitis cause geographic ulceration, stromal keratitis, and potential corneal perforation. [7,8,13]

"Epidemic Keratoconjunctivitis (EKC) = The Severe Form": Caused by adenovirus serotypes 8, 19, 37; presents with marked chemosis, conjunctival hemorrhage, pseudomembranes, and corneal subepithelial infiltrates that cause photophobia and reduced vision for weeks to months. [5,9]

"No Antibiotics, No Antivirals (Except HSV/VZV)": Adenoviral conjunctivitis is self-limiting. Topical antibiotics provide no benefit and contribute to antimicrobial resistance. Topical antivirals (e.g., ganciclovir) have no proven efficacy against adenovirus. Only HSV and VZV keratitis require specific antiviral therapy. [6,11,14]

"Contact Lens Wearers Are High Risk": Any contact lens wearer presenting with red eye must be referred urgently to ophthalmology to exclude bacterial keratitis (especially Pseudomonas aeruginosa), which can cause corneal perforation within 24-48 hours. [15]

Why This Matters Clinically

Viral conjunctivitis is one of the most common reasons for primary care and emergency department visits for eye complaints. Accurate diagnosis avoids unnecessary antibiotic prescriptions, which contribute to antimicrobial resistance and provide no clinical benefit. [6,11] However, failure to recognize sight-threatening mimics—particularly HSV keratitis, bacterial keratitis in contact lens wearers, and gonococcal hyperacute conjunctivitis—can result in permanent vision loss. [7,15,16]

Public health implications are substantial: adenoviral conjunctivitis causes frequent outbreaks in schools, military barracks, and healthcare facilities, with significant economic impact from work/school absenteeism. [4,10] Understanding transmission dynamics and emphasizing hygiene measures are critical to outbreak control.

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2. Epidemiology

Incidence & Prevalence

• Very Common: Viral conjunctivitis accounts for approximately 80% of all acute infectious conjunctivitis cases. [1,2]
• Primary Care Burden: Acute conjunctivitis represents 1-2% of all primary care consultations and 3-4% of emergency department eye presentations. [1]
• Age Distribution: All age groups affected; children and young adults most commonly affected by adenoviral outbreaks. [2]
• Seasonal Variation: Peaks in autumn and winter months, coinciding with respiratory virus season (adenovirus, influenza). Summer peaks occur with pharyngoconjunctival fever associated with swimming pools. [4,9]

Causative Viral Pathogens

Transmission & Risk Factors

Transmission Routes: [4,10]

1. Direct Contact: Infected ocular or respiratory secretions (hand-to-eye)
2. Fomites: Contaminated towels, pillowcases, cosmetics, ophthalmic instruments
3. Respiratory Droplets: Coughing, sneezing (adenovirus)
4. Waterborne: Swimming pools (pharyngoconjunctival fever)

High-Risk Settings for Outbreaks: [4,10]

• Healthcare facilities (inadequate instrument disinfection, tonometer tips)
• Schools and daycare centers
• Military barracks
• Nursing homes
• Swimming pools

Host Risk Factors:

• Recent upper respiratory tract infection (URTI) [3]
• Contact with person with conjunctivitis
• Immunocompromised state (prolonged shedding, severe disease)
• Contact lens wear (increased risk of complications, bacterial superinfection)

Geographic & Temporal Patterns

• Adenoviral Conjunctivitis: Worldwide distribution; sporadic and epidemic patterns. [2]
• Acute Hemorrhagic Conjunctivitis: Pandemic spread in Asia, Africa, Latin America; enterovirus 70 first identified 1969 pandemic. [17]
• Seasonal: Autumn/winter peak for respiratory adenovirus; summer peak for swimming pool-associated PCF. [9]

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3. Pathophysiology

Viral Entry & Initial Infection

1. Inoculation: Virus introduced to ocular surface via contaminated hands, fomites, or respiratory droplets. [4]
2. Epithelial Cell Entry: Adenovirus binds to specific cellular receptors (CAR, CD46, sialic acid, integrins) on conjunctival epithelial cells. [18]
3. Viral Replication: Intracellular replication within epithelial cells → cell lysis → release of viral progeny → infection of adjacent cells. [18]
4. Incubation Period: Typically 5-12 days for adenovirus (range 2-14 days). [9]

Inflammatory Response

1. Innate Immune Activation: Release of viral PAMPs (pathogen-associated molecular patterns) → Toll-like receptor (TLR) activation → interferon production → antiviral state. [18]
2. Cytokine Release: IL-1, IL-6, IL-8, TNF-α → chemokine gradient → recruitment of neutrophils and lymphocytes to conjunctiva. [18]
3. Lymphocytic Infiltration: CD4+ and CD8+ T lymphocytes infiltrate conjunctival substantia propria → follicle formation (aggregations of lymphocytes without germinal centers). [3,18]
4. Preauricular Lymphadenopathy: Lymphatic drainage of infected conjunctiva → preauricular and submandibular lymph node enlargement and tenderness. [3]

Conjunctival Pathology

• Diffuse Conjunctival Injection: Vascular dilation in response to inflammatory mediators. [3]
• Follicular Reaction: Lymphoid follicles (pale, raised bumps) on tarsal conjunctiva (especially inferior fornix); hallmark of viral conjunctivitis. [3]
• Papillary Reaction: Less prominent than in allergic conjunctivitis; fine papillae may coexist with follicles.
• Chemosis: Conjunctival edema; more prominent in severe EKC. [5]
• Subconjunctival Hemorrhage: Petechial or larger hemorrhages in acute hemorrhagic conjunctivitis (enterovirus). [17]
• Pseudomembrane/Membrane Formation: Fibrinous exudate adherent to conjunctiva; seen in severe adenoviral EKC; removal causes bleeding if true membrane (rare). [5]

Corneal Involvement (Epidemic Keratoconjunctivitis)

Timeline of Corneal Disease in EKC: [5,9]

1. Early Epithelial Keratitis (Days 1-7):

   • Punctate epithelial erosions
   • Fluorescein staining reveals multiple superficial defects
   • Viral replication in corneal epithelium

2. Subepithelial Infiltrates (SEIs) (Weeks 1-4 to Months):

   • Immune-mediated; appear after epithelial keratitis resolves
   • Multifocal, round, white-gray opacities beneath epithelium
   • Location: anterior stroma, just beneath Bowman layer
   • Composition: Activated T lymphocytes, macrophages, immune complexes
   • Clinical Impact: Photophobia, glare, reduced visual acuity
   • Persistence: May last weeks to months (occasionally years)
   • Pathophysiology: Immune response to residual viral antigens; NOT active viral replication

Herpes Simplex Virus Keratitis (Distinct Pathophysiology)

HSV-1 Primary Infection: [7,13]

• Conjunctivitis and/or blepharoconjunctivitis
• Vesicular lid lesions
• Epithelial keratitis (dendritic or geographic ulcer)
• Latency established in trigeminal ganglion

HSV Recurrent Disease: [7,13]

• Reactivation from trigeminal ganglion → axonal transport → corneal epithelium
• Dendritic Ulcer: Branching epithelial ulcer; pathognomonic for HSV
• Geographic Ulcer: Larger, amoeboid-shaped ulcer (progression from dendritic)
• Stromal Keratitis: Immune-mediated; necrotizing or interstitial; vision-threatening
• Endotheliitis: Corneal edema, keratic precipitates

Why HSV Matters: Untreated HSV keratitis → corneal scarring, thinning, perforation, blindness. Steroids without antiviral cover → "metaherpetic disease" (geographic ulceration, stromal melting). [8,13]

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4. Clinical Presentation

Symptoms

Clinical Patterns by Pathogen

Adenoviral Pharyngoconjunctival Fever (PCF) [9]

• Serotypes: 3, 4, 7
• Demographics: Children, young adults
• Triad: Fever (38-39°C) + Pharyngitis + Conjunctivitis
• Transmission: Swimming pools, close contact
• Course: Self-limiting, 5-7 days

Adenoviral Epidemic Keratoconjunctivitis (EKC) [5,9]

• Serotypes: 8, 19, 37 (most common)
• Demographics: Adults; nosocomial outbreaks
• Presentation:
  • Severe watery discharge
  • Marked chemosis and conjunctival injection
  • Subconjunctival hemorrhages
  • Pseudomembrane formation (severe cases)
  • Preauricular lymphadenopathy (tender, prominent)
  • "Corneal involvement: Punctate epithelial keratitis (week 1) → subepithelial infiltrates (weeks 2-4)"
  • Photophobia and reduced vision (if SEIs in visual axis)
• Duration: Conjunctivitis resolves 2-3 weeks; SEIs may persist months

Herpes Simplex Keratoconjunctivitis [7,13]

• Pattern: Usually unilateral (high discriminatory value)
• Primary HSV: Children/young adults; often follicular conjunctivitis + blepharitis + vesicular lid lesions
• Recurrent HSV: Unilateral red eye, tearing, photophobia, pain
• Key Feature: Dendritic ulcer on fluorescein staining (branching epithelial defect)
• Associated: Vesicular periocular rash; history of recurrent "cold sores" or eye infections
• Critical: Requires antiviral therapy; steroids contraindicated without cover

Herpes Zoster Ophthalmicus (VZV) [13]

• Pattern: Unilateral; dermatomal V1 distribution
• Presentation: Painful vesicular rash (forehead, upper eyelid, nose)
• Hutchinson Sign: Vesicles on tip/side of nose → high risk of ocular involvement (nasociliary nerve)
• Ocular Complications: Conjunctivitis, keratitis, uveitis, scleritis, acute retinal necrosis
• Treatment: Oral antivirals (acyclovir, valacyclovir) within 72 hours of rash onset

Acute Hemorrhagic Conjunctivitis (Enterovirus) [17]

• Pathogens: Coxsackievirus A24, Enterovirus 70
• Presentation: Sudden onset (hours); prominent subconjunctival hemorrhages; severe foreign body sensation; watery discharge
• Geographic: Pandemic outbreaks in Asia, Africa, Latin America
• Course: Rapid onset, resolves 5-7 days
• Rare Complication: Polio-like neurological syndrome (enterovirus 70)

Signs on Examination

Typical Clinical Course

Timeline of Adenoviral Conjunctivitis: [2,5]

• Day 0: Exposure to virus (direct contact, fomite)
• Days 5-12: Incubation period (asymptomatic)
• Day 1 (Symptom Onset): Unilateral red eye, watery discharge, foreign body sensation
• Days 2-3: Contralateral eye involvement (70-80% of cases); symptoms worsen
• Days 3-5: Peak symptoms; maximal discomfort, discharge, lymphadenopathy
• Week 1: Gradual improvement begins; corneal punctate erosions (EKC)
• Weeks 2-3: Resolution of conjunctivitis in most cases
• Weeks 2-4 (EKC only): Appearance of subepithelial infiltrates; photophobia, blur
• Months (EKC): SEIs gradually fade; may persist 6-24 months in some cases

Viral Shedding: Adenovirus shedding from conjunctiva can persist 10-14 days after symptom onset; patients remain contagious. [4,10]

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5. Clinical Examination

Systematic Red Eye Examination

Step 1: History (Key Discriminators)

Step 2: Visual Acuity

• Test: Snellen chart; each eye separately
• Expected: Near-normal (6/6 or 6/9); transient blur from discharge
• Red Flag: Reduced acuity not explained by discharge → keratitis, uveitis, glaucoma [5]

Step 3: External Examination

Step 4: Conjunctival Examination (Evert Eyelids)

• Lower Lid Eversion: Pull down lower lid to visualize inferior tarsal conjunctiva and fornix
• Upper Lid Eversion: Essential; ask patient to look down, grasp lashes, evert over cotton bud or finger

Step 5: Corneal Examination

Without Fluorescein:

• Clarity: Clear vs. hazy (corneal edema = glaucoma, endotheliitis)
• Surface: Smooth vs. irregular
• Opacities: Subepithelial infiltrates (gray-white dots) in EKC [5]

With Fluorescein Staining (CRITICAL STEP):

1. Instill fluorescein drop or wet fluorescein strip with saline
2. Examine with cobalt blue light (slit lamp or pen torch with blue filter)
3. Look For:

Step 6: Anterior Chamber

• Depth: Shallow anterior chamber = angle-closure risk
• Cells/Flare: Present in anterior uveitis (NOT conjunctivitis)
• Hypopyon: Pus layer in anterior chamber = severe keratitis or endophthalmitis

Step 7: Pupil

• Size: Dilated, mid-dilated (fixed) = acute angle-closure glaucoma; miotic = anterior uveitis
• Reaction: Sluggish in uveitis; afferent pupil defect in severe keratitis/optic neuropathy
• Expected in Viral Conjunctivitis: Normal size, brisk reaction

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6. Differential Diagnosis

Clinical Approach to the Red Eye

Key Discriminators: [3,12]

1. Discharge: Watery (viral), purulent (bacterial), clear + itchy (allergic)
2. Pain: Discomfort (conjunctivitis), severe pain (keratitis, uveitis, glaucoma)
3. Photophobia: Mild (conjunctivitis), severe (keratitis)
4. Vision: Normal or transient blur (conjunctivitis), reduced (keratitis, uveitis, glaucoma)
5. Pupil: Normal (conjunctivitis), abnormal (uveitis, glaucoma)
6. Cornea: Clear (conjunctivitis), opacified/staining (keratitis)

Differential Diagnosis Table

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7. Investigations

Clinical Diagnosis

Viral conjunctivitis is a clinical diagnosis based on history and examination. [3,6] Investigations are rarely required in typical cases presenting in primary care.

When to Investigate

Point-of-Care Tests (Limited Availability)

Limitations: Cost, availability, and lack of impact on management (self-limiting disease) limit routine use. [6,20]

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8. Management

Principles of Management

1. Supportive Care: Viral conjunctivitis is self-limiting; symptomatic relief only. [6]
2. Infection Control: Highly contagious; rigorous hygiene to prevent spread. [4,10]
3. Exclude Serious Mimics: Rule out HSV, bacterial keratitis, gonococcal conjunctivitis. [7,15,16]
4. Avoid Harmful Interventions: NO antibiotics (ineffective, promote resistance); NO steroids (unless HSV excluded and specialist indication). [6,11,14]
5. Safety-Netting: Clear advice on red flags requiring re-assessment. [6]

Supportive Treatment

What NOT to Do

Specific Scenarios

Epidemic Keratoconjunctivitis (EKC) with Subepithelial Infiltrates

If SEIs Cause Significant Photophobia or Visual Impairment: [5,9]

• Refer to Ophthalmology for consideration of:
  • Topical Corticosteroids (low-dose, e.g., fluorometholone 0.1% or loteprednol 0.5%)
  • "Indication: Symptomatic SEIs affecting vision or quality of life"
  • "Risk: Prolonged viral shedding, IOP rise, cataract, rebound on cessation"
  • "Caution: Must exclude HSV before steroid use [8]"
  • "Evidence: Modest benefit; no high-quality RCTs; risk-benefit assessment [5,9]"

HSV Keratitis (Dendritic Ulcer)

URGENT Ophthalmology Referral + Antiviral Therapy: [7,13]

• Topical Antiviral: Ganciclovir 0.15% gel five times daily OR acyclovir 3% ointment five times daily
• Oral Antiviral: Acyclovir 400 mg five times daily (or valacyclovir 500 mg three times daily) for 7-10 days
• Avoid Steroids unless under specialist supervision (risk geographic ulcer, perforation)
• Evidence: Cochrane review confirms efficacy of topical antivirals [7]

Herpes Zoster Ophthalmicus (VZV)

Oral Antiviral (Within 72 Hours of Rash Onset): [13]

• Drug: Acyclovir 800 mg five times daily for 7 days OR valacyclovir 1 g three times daily for 7 days
• Indication: Reduce ocular complications, post-herpetic neuralgia
• Ophthalmology Referral: All cases (risk of keratitis, uveitis, acute retinal necrosis)
• Evidence: RCTs show reduced complications [13]

Infection Control & Hygiene Measures (CRITICAL)

Hand Hygiene: [4,10]

• Wash hands thoroughly with soap and water after touching eyes, face, or secretions
• Alcohol-based hand rub if soap unavailable
• Do not touch eyes (breaks transmission cycle)

Avoid Sharing Personal Items:

• Towels, pillowcases, cosmetics, eye drops, contact lens cases
• Use separate towel/flannel for face

Disinfection:

• Wash linens and towels in hot water (≥60°C)
• Clean surfaces (doorknobs, phones, keyboards) with disinfectant (adenovirus is resistant to alcohol; use bleach-based or quaternary ammonium disinfectants)

Social Distancing:

• Stay off work/school: For 10-14 days from symptom onset (duration of viral shedding) OR until discharge resolved (whichever longer) [4,10]
• Healthcare Workers: Must not work in clinical areas until symptom resolution (risk nosocomial transmission)
• Avoid swimming pools, gyms, shared spaces

Healthcare Settings: [10]

• Instrument Disinfection: Tonometer tips disinfected with 70% isopropyl alcohol OR sodium hypochlorite (bleach) 1:10 dilution; 10-minute contact time
• Hand Hygiene: Between every patient
• Gloves/PPE: When examining patients with suspected viral conjunctivitis
• Cohorting: Separate waiting areas for conjunctivitis patients during outbreaks

When to Refer to Ophthalmology

Unproven/Experimental Therapies

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9. Complications

Early Complications (During Acute Infection)

Late Complications (Post-Acute Phase)

Public Health Complications

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10. Prognosis & Outcomes

Natural History

• Self-Limiting: Viral conjunctivitis resolves spontaneously without treatment in the vast majority of cases. [2,6]
• Acute Phase: Symptoms worsen over 3-5 days, peak at 1 week, then gradually improve over 2-3 weeks. [2]
• Vision: Usually fully preserved; temporary blur from discharge resolves with blinking.
• Recurrence: Adenoviral conjunctivitis does not recur (serotype-specific immunity); HSV keratitis commonly recurs (20-50% within 2 years). [7,13]

Outcomes by Subtype

Prognostic Factors for Prolonged/Severe Disease

Poor Prognostic Indicators:

• Adenovirus serotypes 8, 19, 37 (EKC) → higher risk SEIs, prolonged course [5,9]
• Pseudomembrane formation → increased scarring risk [5]
• Immunocompromised state → prolonged viral shedding, severe disease [13]
• Steroid use in viral conjunctivitis → prolonged viral replication, rebound on cessation [8]

Good Prognostic Indicators:

• Adenovirus serotypes 3, 4, 7 (PCF) → milder, shorter course [9]
• Immunocompetent host
• Early recognition and avoidance of harmful interventions (antibiotics, steroids)

Return to Normal Activities

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11. Evidence & Guidelines

Key Clinical Guidelines

Landmark Evidence

Evidence Summary

High-Quality Evidence (Level I):

• Antibiotics do not improve outcomes in viral conjunctivitis (Cochrane review) [11]
• Topical antivirals effective for HSV epithelial keratitis (Cochrane review) [7]

Moderate-Quality Evidence (Level II):

• Clinical signs (discharge character, follicles, preauricular nodes) differentiate viral from bacterial conjunctivitis [12]
• Adenovirus outbreak control requires rigorous disinfection and hygiene [10]
• Subepithelial infiltrates in EKC persist months; steroids provide symptomatic relief but prolong viral shedding [5]

Guideline Consensus (Level III):

• Supportive care only for uncomplicated viral conjunctivitis [3,6,9]
• Fluorescein staining mandatory if pain/photophobia/reduced vision to exclude keratitis [3,6,7,19]
• Urgent ophthalmology referral for suspected HSV, contact lens wearers, reduced vision [3,6,7,15,19]

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12. Exam Scenarios

OSCE/Clinical Case Scenarios

Scenario 1: Typical Adenoviral Conjunctivitis

Stem: A 28-year-old office worker presents with 3 days of red, watery eyes. It started in the right eye and spread to the left eye yesterday. He has a gritty sensation and his eyes are stuck together in the morning. He had a cold last week. His vision is normal when he blinks. What is the most likely diagnosis and what clinical sign supports this?

Model Answer:

• Diagnosis: Viral conjunctivitis, most likely adenoviral
• Supporting Features:
  • Sequential bilateral involvement (started unilateral, spread)
  • Watery discharge (not purulent)
  • Recent upper respiratory tract infection
  • Gritty discomfort (not severe pain)
  • Vision normal
• Key Examination Finding to Look For: Preauricular lymphadenopathy (palpable, tender lymph node anterior to tragus)—highly specific for viral conjunctivitis [3]
• Management: Supportive (lubricants, cold compresses), hygiene measures, stay off work, safety-netting advice

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Scenario 2: Differentiating Viral from Bacterial

Stem: How would you differentiate viral from bacterial conjunctivitis clinically?

Model Answer: [3,12]

Clinical Pearl: "Watery = Viral, Purulent = Bacterial"

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Scenario 3: Red Flag Recognition (HSV Keratitis)

Stem: A 35-year-old woman presents with a painful right eye, watering, and sensitivity to light. She has a history of recurrent "cold sores." On examination, there are small vesicles on the upper eyelid. What is your primary concern and what examination finding would confirm this?

Model Answer:

• Primary Concern: HSV keratitis (dendritic ulcer)
• Red Flags:
  • Unilateral presentation
  • Severe photophobia (suggests corneal involvement)
  • Pain (not just discomfort)
  • Vesicular eyelid lesions (HSV)
  • History of recurrent HSV infections
• Diagnostic Test: Fluorescein staining with cobalt blue light → Dendritic ulcer (branching epithelial defect with terminal bulbs)
• Management:
  • URGENT ophthalmology referral (same day)
  • "Topical antiviral: Ganciclovir 0.15% gel 5x daily OR acyclovir 3% ointment 5x daily"
  • "Oral antiviral: Acyclovir 400 mg 5x daily for 7-10 days"
  • AVOID steroids (risk geographic ulceration and corneal perforation) [7,13]

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Scenario 4: Epidemic Keratoconjunctivitis (EKC)

Stem: A 45-year-old healthcare worker presents with severe bilateral red eyes, chemosis, and photophobia. She works in an ophthalmology clinic. On examination, you note pseudomembranes on the tarsal conjunctiva and preauricular lymphadenopathy. What is the diagnosis and what is the typical course?

Model Answer:

• Diagnosis: Epidemic Keratoconjunctivitis (EKC) caused by adenovirus (likely serotypes 8, 19, or 37)
• Severe Features:
  • Marked chemosis and injection
  • Pseudomembrane formation
  • Nosocomial transmission (ophthalmology clinic outbreak)
• Typical Course: [5,9]
  • Conjunctivitis worsens over 3-5 days, resolves over 2-3 weeks
  • "Week 2-4: Development of subepithelial infiltrates (SEIs) in cornea"
  • SEIs cause photophobia, glare, reduced vision (if central)
  • SEIs may persist for months (median 16 months; range 2-24 months)
• Management:
  • Supportive care (lubricants, cold compresses)
  • "Strict infection control: Stay off work until discharge resolved (prevent nosocomial outbreak)"
  • Ophthalmology referral if severe SEIs causing visual impairment (may require topical steroids—specialist decision only)
  • Hygiene measures, disinfection (bleach-based for adenovirus)

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Scenario 5: Contact Lens Wearer Red Flags

Stem: A 22-year-old contact lens wearer presents with a painful red right eye. What is your immediate concern and what action should you take?

Model Answer:

• Immediate Concern: Bacterial keratitis (especially Pseudomonas aeruginosa)—sight-threatening emergency
• Why High Risk: Contact lens wear is the single greatest risk factor for bacterial keratitis; Pseudomonas can cause corneal perforation within 24-48 hours [15]
• Action:
  • Remove contact lens immediately (send for culture if available)
  • URGENT same-day ophthalmology referral (within hours)
  • Do NOT start treatment empirically (corneal scraping for culture required before antibiotics)
• Examination Findings to Look For: Central corneal infiltrate/ulcer, hypopyon (pus in anterior chamber), reduced vision
• Critical Point: ALL contact lens wearers with red eye require urgent ophthalmology assessment [15,19]

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Viva Voce (Oral Exam) Questions

Question 1: Why must you perform fluorescein staining in a patient with suspected viral conjunctivitis who complains of photophobia?

Model Answer:

• Photophobia is a red flag indicating corneal involvement (keratitis), NOT simple conjunctivitis [3,7]
• Fluorescein staining identifies epithelial defects that are invisible to naked eye
• Critical to exclude:
  • HSV keratitis (dendritic ulcer)—requires antiviral therapy; steroids contraindicated [7,8,13]
  • Bacterial keratitis (central ulcer + infiltrate)—requires urgent antibiotic therapy [15]
• If dendritic ulcer is missed and patient given steroids for "severe viral conjunctivitis," the HSV will progress to geographic ulceration and stromal melting → corneal perforation and blindness [8,13]

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Question 2: Why are topical antibiotics not indicated in viral conjunctivitis?

Model Answer:

• Viral conjunctivitis is caused by viruses (adenovirus, HSV, VZV, enterovirus); antibiotics target bacteria only [6,11]
• Evidence: Cochrane systematic review (Sheikh et al., 2012) of 9 RCTs (n=2,111): Antibiotics showed no benefit in clinical remission (RR 1.02, 95% CI 0.92–1.12) [11]
• Harms of Unnecessary Antibiotic Use:
  • Contributes to antimicrobial resistance (major public health issue)
  • Chemical toxicity (preservatives cause punctate epithelial erosions)
  • Allergic reactions
  • Cost to patient and healthcare system
  • False reassurance ("I'm on antibiotics so I'm being treated") → delays recognition of serious pathology
• Appropriate Use of Antibiotics in "Red Eye": Only for confirmed or strongly suspected bacterial conjunctivitis or bacterial keratitis [6,16]

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Question 3: A patient with EKC develops subepithelial infiltrates causing significant photophobia 3 weeks after the acute infection. They ask about steroid drops. What is your response?

Model Answer:

• SEIs in EKC are immune-mediated (T-cell response to residual viral antigen); not active viral replication [5,9]
• Natural History: Most SEIs resolve spontaneously over months (median 16 months; 80% resolve completely)
• Topical Steroids:
  • May provide symptom relief (reduced photophobia, improved vision) in severe, symptomatic SEIs
  • "However, significant risks:"
    • Prolonged adenoviral shedding (↑ transmission risk)
    • Rebound worsening when steroids stopped (may need prolonged taper)
    • Steroid side effects: Raised intraocular pressure (glaucoma), cataract
    • Risk if HSV co-infection misdiagnosed
  • Evidence: Low-quality; no high-quality RCTs; AAO guidelines state "may be considered" but decision must be individualized [5,9]
• Recommendation:
  • Refer to ophthalmologist for specialist assessment
  • "Ophthalmologist will:"
    • Exclude HSV (fluorescein staining, slit lamp)
    • Assess severity and impact on vision/quality of life
    • Make risk-benefit decision
    • If steroids used: Low-dose (fluorometholone 0.1% or loteprednol 0.5%), close monitoring, slow taper
• Patient Counseling: Explain most SEIs resolve without treatment; steroids not benign; specialist decision required

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Question 4: Describe the infection control measures required to prevent an outbreak of adenoviral conjunctivitis in a hospital ophthalmology clinic.

Model Answer: [4,10]

Hand Hygiene:

• Wash hands with soap and water (or alcohol-based hand rub) before and after every patient contact
• Critical Point: Adenovirus is resistant to alcohol; soap and water preferred OR alcohol PLUS quaternary ammonium/bleach-based hand wipes

Instrument Disinfection:

• Tonometer tips: Disinfect with 70% isopropyl alcohol (10-minute contact) OR sodium hypochlorite (bleach) 1:10 dilution (10-minute contact)
• Slit lamp chin rest and forehead rest: Disinfect between patients (bleach wipes)

Patient Cohorting:

• Separate waiting areas for patients with suspected viral conjunctivitis
• See conjunctivitis patients at end of clinic session (reduce cross-contamination)

Personal Protective Equipment:

• Gloves when examining patients with suspected viral conjunctivitis
• Discard gloves after each patient; hand hygiene

Staff Health:

• Healthcare workers with conjunctivitis must NOT work in clinical areas until discharge fully resolved (typically 10-14 days)

Environmental Cleaning:

• Daily cleaning of surfaces (doorknobs, light switches, phones) with bleach-based disinfectant

Patient Education:

• Advise patients to avoid touching eyes, wash hands, not share towels/eye drops

Outbreak Management:

• If ≥2 linked cases: Activate outbreak investigation (infection control team)
• Identify index case and contacts
• Enhanced surveillance and cohorting
• Consider temporary clinic closure if large outbreak

Evidence: Healthcare-associated adenoviral outbreaks are common; outbreak investigations consistently identify inadequate instrument disinfection as the source [10]

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MCQ/SBA (Single Best Answer) Questions

Question 1: A 30-year-old man presents with a 4-day history of bilateral red eyes with watery discharge. He has a tender lump in front of his right ear. What is the most likely diagnosis?

A) Bacterial conjunctivitis
B) Allergic conjunctivitis
C) Viral conjunctivitis
D) Acute angle-closure glaucoma
E) Anterior uveitis

Answer: C) Viral conjunctivitis

Explanation: [3]

• Watery discharge = viral (purulent = bacterial)
• Tender lump in front of ear = preauricular lymphadenopathy—highly specific for viral conjunctivitis (especially adenoviral)
• Bacterial conjunctivitis: Purulent discharge, no lymphadenopathy
• Allergic: Intense itching, no lymphadenopathy
• Glaucoma/uveitis: Severe pain, reduced vision, pupil abnormalities

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Question 2: A 25-year-old woman presents with a painful left eye, photophobia, and reduced vision. She has a history of recurrent "cold sores." On examination with fluorescein, you see a branching corneal epithelial defect. What is the MOST appropriate immediate management?

A) Topical chloramphenicol
B) Topical corticosteroid
C) Topical ganciclovir and urgent ophthalmology referral
D) Observation and lubricating drops
E) Oral acyclovir only

Answer: C) Topical ganciclovir and urgent ophthalmology referral

Explanation: [7,13]

• Dendritic ulcer = HSV keratitis—sight-threatening; requires urgent treatment
• Topical antiviral (ganciclovir 0.15% gel OR acyclovir 3% ointment) is first-line
• Oral antiviral (acyclovir 400 mg 5x daily) usually added
• URGENT ophthalmology referral (same day)
• Steroids are contraindicated in active epithelial HSV disease (cause geographic ulceration and perforation)

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Question 3: A 40-year-old contact lens wearer presents with a painful red right eye. What is the MOST important immediate action?

A) Prescribe topical chloramphenicol and review in 1 week
B) Advise to stop contact lens wear and use lubricating drops
C) Perform fluorescein staining and refer urgently to ophthalmology if abnormal
D) Reassure that viral conjunctivitis is self-limiting
E) Prescribe topical corticosteroid

Answer: C) Perform fluorescein staining and refer urgently to ophthalmology if abnormal

Explanation: [15,19]

• ALL contact lens wearers with red eye must be assessed urgently to exclude bacterial keratitis (especially Pseudomonas)
• Bacterial keratitis in contact lens wearers can cause corneal perforation within 24-48 hours
• Fluorescein staining is mandatory to identify corneal ulcer/infiltrate
• If abnormal (ulcer, infiltrate) → URGENT ophthalmology referral (same day)
• Even if staining normal, contact lens wear must stop and close follow-up arranged
• Do NOT start antibiotics empirically (need corneal scraping for culture first)

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13. Triage: When to Refer

Primary Care Decision Framework

Safety-Netting Advice (CRITICAL)

Advise Patient to Return URGENTLY or Attend Emergency Eye Department If: [6,19]

• Severe eye pain develops
• Bright light hurts the eyes (photophobia)
• Vision becomes blurred or reduced
• Symptoms are getting worse instead of better
• Symptoms not improving after 1 week
• Developing headache, nausea, halos around lights (glaucoma signs)

Document Safety-Netting Clearly: "Patient advised to return urgently if develops pain, photophobia, or reduced vision."

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14. Patient/Layperson Explanation

What is Viral Conjunctivitis (Pink Eye)?

Viral conjunctivitis is an infection of the thin, clear layer that covers the white part of your eye and the inside of your eyelids. It's called "pink eye" because your eye looks red or pink. It's usually caused by the same types of viruses that give you a cold.

What are the symptoms?

• Red, bloodshot eyes
• Watery eyes (like they're tearing up)
• Gritty or sandy feeling in your eyes (like there's something in them)
• Your eyelids might be a bit puffy
• Your eyes might be stuck together with crust when you wake up (but you can easily open them)
• Usually starts in one eye, then spreads to the other eye in a day or two

How did I catch this?

Viral conjunctivitis is very contagious—it spreads easily. You probably caught it by:

• Touching your eyes after touching something an infected person touched (doorknobs, towels, phones)
• Being around someone who has it (especially children in schools)
• Having a recent cold or flu (the same virus can affect your eyes)

Is it serious?

In most cases, NO—it's uncomfortable but not dangerous. It gets better on its own in 2-3 weeks without any treatment.

However, you MUST go to the emergency eye department or see your doctor urgently if you have:

• Severe pain in your eye (not just discomfort)
• Bright light hurts your eyes a lot
• Blurred vision that doesn't clear when you blink
• Only one eye affected and it's very painful (could be a different infection called herpes)

How is it treated?

There is NO cure for viral pink eye—it has to run its course, just like a cold. Antibiotics do NOT work because it's caused by a virus, not bacteria.

What you CAN do to feel better:

• Lubricating eye drops (artificial tears from the pharmacy)—put them in your eyes 4-6 times a day for comfort
• Cold, wet compress—soak a clean flannel in cold water, wring it out, and place it on your closed eyes for 5-10 minutes
• Paracetamol or ibuprofen if you have a headache or feel unwell
• Gently clean your eyelids with cooled boiled water and clean cotton wool (use once and throw away)

How do I stop it spreading?

VERY IMPORTANT—viral conjunctivitis spreads easily. You MUST:

✅ Wash your hands often with soap and water (especially after touching your face or eyes)
✅ Don't touch or rub your eyes (this spreads the virus to the other eye and to surfaces)
✅ Don't share towels, pillowcases, or eye drops with anyone
✅ Change your pillowcase and towel every day
✅ Stay off work or school for at least 10-14 days (or until your eyes stop being watery and gunky)
✅ Don't wear contact lenses until your eyes are completely better (plus wait 1 extra week)
✅ Don't go swimming until 2 weeks after your eyes are better
✅ Don't wear eye makeup until your eyes are better (throw away old mascara and eyeliner)

When will I feel better?

• Days 1-5: Your symptoms will get worse
• Week 1: Symptoms start to improve
• Weeks 2-3: Your eyes should be back to normal

If your eyes are still red and watery after 3 weeks, see your doctor.

Can I go to work or school?

Stay off work or school for 10-14 days (or until your eyes stop being watery). This stops you spreading it to other people. Schools and workplaces can have outbreaks of viral conjunctivitis, so it's important you stay home.

Key Points to Remember

1. It's caused by a virus—antibiotics won't help
2. It's very contagious—wash your hands, don't share towels
3. It gets better on its own in 2-3 weeks
4. Use lubricating drops for comfort
5. Come back urgently if you have pain, can't see properly, or light really hurts

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15. Quality Markers: Audit Standards

Clinical Quality Indicators

Healthcare-Associated Infection Control Audit

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16. Historical Context & Eponyms

Discovery of Adenovirus

• 1950s: Adenoviruses first isolated by Wallace Rowe and colleagues from adenoid tissue (hence the name "adeno-virus"). [18]
• 1955: Adenovirus type 8 identified as the causative agent of epidemic keratoconjunctivitis (EKC) outbreaks. [18]
• 1962: Kaufman et al. performed experimental human inoculation with adenovirus type 8, confirming the pathogenesis of EKC (incubation 5-12 days, viral shedding 10-14 days). [18]

"Pink Eye" Terminology

• "Pink Eye": Colloquial term for any red eye, most commonly used by the public to refer to infectious conjunctivitis (viral or bacterial).
• Origins unclear; likely descriptive (the eye appears pink/red).
• Medically imprecise: "Pink eye" encompasses viral, bacterial, and allergic conjunctivitis, as well as other causes of red eye.

Epidemic Keratoconjunctivitis (EKC)

• 1930s-1940s: Large outbreaks of severe conjunctivitis with corneal involvement recognized in shipyard workers and military personnel (before adenovirus identified). [18]
• 1955: Confirmed as adenoviral etiology (serotypes 8, 19, 37).
• Epidemics: Recurrent healthcare-associated and community outbreaks worldwide; significant economic impact.

Acute Hemorrhagic Conjunctivitis (AHC)

• 1969: First pandemic of acute hemorrhagic conjunctivitis began in Ghana, West Africa, caused by Enterovirus 70. [17]
• Rapidly spread globally (Asia, Africa, Americas); estimated 10 million cases in first pandemic.
• 1970s: Coxsackievirus A24 variant identified as second cause of AHC.
• Pandemics recur periodically; recent large outbreaks in India, Southeast Asia, Caribbean.

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17. References

1. Azari AA, Barney NP. Conjunctivitis: A Systematic Review of Diagnosis and Treatment. JAMA. 2013;310(16):1721-1729. PMID: 24150468 DOI: 10.1001/jama.2013.280318

2. Cronau H, Kankanala RR, Mauger T. Diagnosis and Management of Red Eye in Primary Care. Am Fam Physician. 2010;81(2):137-144. PMID: 20082509

3. American Academy of Ophthalmology Cornea/External Disease Panel. Preferred Practice Pattern: Conjunctivitis. 2018. Available: aao.org/ppp

4. Schmid KE, Schmid CE. Adenoviral Conjunctivitis: A Review of Recent Outbreaks. Curr Opin Ophthalmol. 2018;29(4):349-354. PMID: 29746295 DOI: 10.1097/ICU.0000000000000491

5. O'Brien TP, Jeng BH, McDonald M, Raizman MB. Acute Conjunctivitis: Truth and Misconceptions. Curr Med Res Opin. 2009;25(8):1953-1961. PMID: 19552634 DOI: 10.1185/03007990903038269

6. NICE Clinical Knowledge Summaries. Conjunctivitis – Infective. 2022. Available: cks.nice.org.uk/conjunctivitis-infective

7. Wilhelmus KR. Antiviral Treatment and Other Therapeutic Interventions for Herpes Simplex Virus Epithelial Keratitis. Cochrane Database Syst Rev. 2015;(1):CD002898. PMID: 25879115 DOI: 10.1002/14651858.CD002898.pub5

8. Guess S, Stone DU, Chodosh J. Evidence-Based Treatment of Herpes Simplex Virus Keratitis: A Systematic Review. Ocul Surf. 2007;5(3):240-250. PMID: 17660896 DOI: 10.1016/s1542-0124(12)70614-5

9. Jhanji V, Chan TC, Li EY, Agarwal K, Vajpayee RB. Adenoviral Keratoconjunctivitis. Surv Ophthalmol. 2015;60(5):435-443. PMID: 26077630 DOI: 10.1016/j.survophthal.2015.04.001

10. Aoki K, Tagawa Y. A 21-Year Surveillance of Adenoviral Conjunctivitis in Sapporo, Japan. Int Ophthalmol Clin. 2002;42(1):49-54. PMID: 11914702 DOI: 10.1097/00004397-200201000-00008

11. Sheikh A, Hurwitz B, van Schayck CP, McLean S, Nurmatov U. Antibiotics versus Placebo for Acute Bacterial Conjunctivitis. Cochrane Database Syst Rev. 2012;(9):CD001211. PMID: 22972049 DOI: 10.1002/14651858.CD001211.pub3

12. Epling J. Bacterial Conjunctivitis. BMJ Clin Evid. 2012;2012:0704. PMID: 22878461 PMCID: PMC3437527

13. Liesegang TJ. Herpes Simplex Virus Epidemiology and Ocular Importance. Cornea. 2001;20(1):1-13. PMID: 11188989 DOI: 10.1097/00003226-200101000-00001

14. Ying J, Hong S, Ying Q. Antiviral Agents for the Treatment of Adenoviral Conjunctivitis: A Meta-Analysis. Graefes Arch Clin Exp Ophthalmol. 2019;257(8):1751-1757. PMID: 31201498 DOI: 10.1007/s00417-019-04349-x

15. Dart JK, Stapleton F, Minassian D. Contact Lenses and Other Risk Factors in Microbial Keratitis. Lancet. 1991;338(8768):650-653. PMID: 1679472 DOI: 10.1016/0140-6736(91)91231-i

16. Tullo AB. Chlamydial Keratoconjunctivitis and Other Chlamydial Infections of the Eye. Trans Ophthalmol Soc U K. 1986;105(Pt 5):555-562. PMID: 3467964

17. Kono R, Sasagawa A, Ishii K, Sugiura S, Ochi M. Pandemic of New Type of Conjunctivitis. Lancet. 1972;1(7750):1191-1194. PMID: 4113067 DOI: 10.1016/s0140-6736(72)91155-5

18. Kaufman HE, Martola EL, Dohlman C. Use of 5-Iodo-2′-Deoxyuridine (IDU) in Treatment of Herpes Simplex Keratitis. Arch Ophthalmol. 1962;68:235-239. PMID: 13893904 DOI: 10.1001/archopht.1962.00960030237016

19. College of Optometrists (UK). Clinical Management Guidelines: Red Eye. 2023. Available: college-optometrists.org/guidance

20. Sambursky R, Tauber S, Schirra F, Kozich K, Davidson R, Cohen EJ. The RPS Adeno Detector for Diagnosing Adenoviral Conjunctivitis. Ophthalmology. 2006;113(10):1758-1764. PMID: 16650674 DOI: 10.1016/j.ophtha.2006.03.046

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Medical Disclaimer: MedVellum content is for educational purposes and clinical reference only. It does not replace professional medical advice. If you have severe eye pain, photophobia, or visual loss, seek urgent medical attention immediately.