What is the differential diagnosis and management plan for a patient with painful eye movement and purulent discharges, considering age, immune status, and past medical history, including any previous eye conditions or surgeries?

Painful Eye Movement with Purulent Discharge: Differential Diagnosis and Management

Immediate Priority: Rule Out Vision-Threatening Emergencies

The presence of painful eye movement with purulent discharge requires immediate evaluation for bacterial keratitis and gonococcal conjunctivitis, both of which can cause corneal perforation and permanent vision loss within 24-48 hours. 1, 2

Critical First Steps

• Perform fluorescein staining immediately to detect corneal involvement—this is mandatory in any case of purulent conjunctivitis, as bacterial keratitis can present with similar symptoms but requires more aggressive management 1, 2
• Obtain conjunctival cultures and Gram stain if gonococcal infection is suspected (sexually active adults, neonates, severe bilateral purulent discharge) 1
• Pain with eye movement specifically suggests corneal or intraocular involvement, not simple conjunctivitis, which typically causes discomfort but not pain with extraocular movements 1, 3

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Differential Diagnosis by Severity

Life-Threatening/Vision-Threatening (Require Immediate Ophthalmology Referral)

Bacterial Keratitis:

• Central or large (>2mm) corneal infiltrate with stromal involvement detected on fluorescein examination 1
• Pain is typically severe and out of proportion to examination findings 1
• Contact lens wear is the most common risk factor in otherwise healthy patients 1
• Requires immediate topical fortified antibiotics (not just standard conjunctivitis treatment) 1

Gonococcal Conjunctivitis:

• Can cause corneal perforation within 24-48 hours if untreated 1, 2
• Presents with severe, rapidly reaccumulating purulent discharge and marked eyelid swelling 1, 4
• Requires immediate systemic antibiotics (ceftriaxone 1g IM/IV) plus topical therapy—topical treatment alone is insufficient 1, 2
• Saline lavage promotes comfort and more rapid resolution 1
• Sexual contacts must be treated and sexual abuse considered in children 1

Herpes Simplex Keratitis:

• Presence of eyelid vesicles is pathognomonic and requires immediate referral 4
• Can progress to stromal keratitis, corneal scarring, perforation, uveitis, and retinitis 2
• Topical corticosteroids are absolutely contraindicated until HSV is ruled out 5

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Moderate to Severe Bacterial Conjunctivitis

Clinical Features:

• Copious purulent discharge with marked inflammation 1
• Mattering and adherence of eyelids on waking 6
• Lack of itching distinguishes from allergic causes 6
• Pain (not just discomfort) suggests corneal involvement 1

Management:

• Obtain cultures if discharge is copious, infection is unresponsive to initial therapy, or patient has history of ocular surgery 1
• Start broad-spectrum topical antibiotics empirically (fluoroquinolones like gatifloxacin 0.5% every 2 hours while awake for first 2 days, then QID for 5 days) 7
• Be aware of increasing MRSA resistance to fluoroquinolones—consider fortified vancomycin if culture shows MRSA 1
• Add cycloplegic agent (cyclopentolate or homatropine) if substantial anterior chamber inflammation is present to decrease pain and prevent synechiae 1

Follow-up:

• Return in 3-4 days if no improvement—earlier if worsening 1
• Daily follow-up required for gonococcal conjunctivitis until resolution 1

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Chlamydial Conjunctivitis

Clinical Features:

• Follicular conjunctivitis with distinctive follicles on bulbar conjunctiva and semilunar fold 2
• Chronic course with preauricular lymphadenopathy 2
• Often associated with concurrent genital infection 1

Management:

• Requires systemic antibiotics (azithromycin 1g PO single dose or doxycycline 100mg PO BID x 7 days)—topical therapy alone is insufficient 1, 2
• Topical antibiotics may be added but are not necessary 1
• Sexual contacts must be treated and sexual abuse considered in children 1

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Age-Specific Considerations

Neonates (0-28 days):

• Any purulent conjunctivitis is an emergency until gonococcal and chlamydial causes are ruled out 2, 8, 4
• Gonococcal infection can lead to septicemia, meningitis, and death 2, 8
• Timing of onset helps narrow differential: gonococcal typically 3-5 days postpartum, chlamydial 5-14 days 9

Contact Lens Wearers:

• High risk for Pseudomonas aeruginosa and other gram-negative organisms 1
• Also at risk for Acanthamoeba and fungal keratitis 1, 5
• Never patch the eye—increases risk of bacterial keratitis 1
• Requires aggressive treatment with fortified antibiotics if keratitis present 1

Immunocompromised Patients:

• Higher risk for severe complications and atypical presentations 2
• Multiple large molluscum lesions may indicate immunocompromised state 1, 2
• Consider fungal, Acanthamoeba, or mycobacterial causes 1

Post-Surgical Patients:

• Pain or red eye after recent ocular surgery must be considered endophthalmitis until proven otherwise 3
• Requires immediate ophthalmology referral for vitreous cultures and intravitreal antibiotics 3

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Management Algorithm

Step 1: Immediate Assessment

• Visual acuity measurement 1
• Fluorescein staining to detect corneal involvement 1, 2
• Evert eyelids to examine tarsal conjunctiva 1
• Check for proptosis or impaired extraocular movements (suggests orbital involvement) 4

Step 2: Risk Stratification

Immediate Ophthalmology Referral if ANY of the following:

• Corneal involvement on fluorescein examination 1, 2
• Severe or rapidly reaccumulating purulent discharge 1, 4
• Pain with eye movement or severe pain 1
• Decreased vision 10
• Contact lens wearer with infiltrate 1
• Recent ocular surgery 1, 3
• Eyelid vesicles 4
• Proptosis or impaired extraocular movements 4
• Neonate with purulent discharge 2, 8, 4

Step 3: Culture Indications

• Suspected gonococcal or chlamydial infection 1
• Corneal infiltrate present 1
• Unresponsive to initial therapy 1
• History of ocular surgery 1
• Contact lens wearer with keratitis 1

Step 4: Empiric Treatment (if no corneal involvement)

• Broad-spectrum topical antibiotic (gatifloxacin, moxifloxacin, or azithromycin) 1, 7
• Avoid corticosteroids until infection is controlled and HSV is ruled out 1, 5
• Supportive care: cold compresses, artificial tears 10
• Strict hand hygiene to prevent transmission 10

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Critical Pitfalls to Avoid

• Never assume "just conjunctivitis" when pain with eye movement is present—this suggests deeper involvement 1, 3
• Never use topical corticosteroids before ruling out HSV keratitis—can cause corneal perforation 1, 5
• Never patch an eye in a contact lens wearer—dramatically increases risk of bacterial keratitis 1
• Never treat gonococcal or chlamydial conjunctivitis with topical antibiotics alone—systemic therapy is mandatory 1, 2
• Never delay referral for suspected bacterial keratitis—hours matter for visual outcome 1