What is the treatment for endophthalmitis in a middle-aged or older adult patient with a history of recent ocular surgery or trauma, presenting with symptoms such as vision loss, eye pain, and redness?

Treatment of Endophthalmitis

Immediate intravitreal injection of antibiotics is the cornerstone of treatment for bacterial endophthalmitis, with vancomycin plus ceftazidime or an aminoglycoside as empiric coverage, and urgent pars plana vitrectomy should be performed in severe cases to remove inflammatory debris and infectious organisms. 1, 2

Diagnostic Approach Before Treatment

• Obtain vitreous and aqueous humor cultures via diagnostic tap before initiating any antimicrobial therapy to identify the causative organism 1, 3, 2
• Perform direct ophthalmoscopic examination to assess the extent of intraocular involvement, particularly whether the macula or vitreous are affected 4, 1
• Determine if infection involves anterior chamber, posterior chamber, or both, as this dictates drug penetration requirements 4

Treatment Algorithm for Bacterial Endophthalmitis

Exogenous (Post-Surgical or Post-Traumatic)

Intravitreal Antibiotics (Primary Treatment):

• Inject vancomycin (for gram-positive coverage) plus ceftazidime or an aminoglycoside (for gram-negative coverage) directly into the vitreous 1, 3, 2
• Multiple injections may be required (average 5.8 injections in severe cases) combined with intravitreal dexamethasone 3
• Critical pitfall: Subconjunctival antibiotic injections alone are ineffective and should never replace intravitreal administration 1, 3

Surgical Intervention:

• Perform pars plana vitrectomy urgently in severe cases (significant vitritis, poor initial visual acuity) as this is sight-saving by removing inflammatory debris and infectious organisms 1, 3, 2, 5
• The evidence for routine early vitrectomy versus tap-and-inject is limited, but vitrectomy is clearly indicated when vision is severely compromised 5

Systemic Antibiotics:

• The role of systemic antibiotics in exogenous bacterial endophthalmitis remains controversial and is not routinely required since infection is confined to the eye 6, 7
• However, systemic antibiotics must be given in endogenous endophthalmitis to treat bacteremia and the primary infection source 2, 7

Treatment Algorithm for Fungal Endophthalmitis

Candida Endophthalmitis

For Fluconazole/Voriconazole-Susceptible Isolates:

• Fluconazole: 800 mg loading dose, then 400-800 mg daily, OR
• Voriconazole: 400 mg IV twice daily for 2 doses, then 300 mg IV/oral twice daily 4, 1, 3
• These azoles achieve adequate concentrations in the posterior segment including vitreous 4

For Resistant Candida Isolates:

• Liposomal amphotericin B with or without oral flucytosine 4, 1

Macular or Vitreous Involvement:

• Combine systemic antifungals with intravitreal injection of amphotericin B (5-10 μg/0.1 mL sterile water) or voriconazole 4, 1, 3
• Consider vitrectomy for sight-threatening lesions near the macula 4, 1

Aspergillus Endophthalmitis

• Administer intravenous amphotericin B plus intravitreal amphotericin B (5-10 μg/0.1 mL sterile water) 1, 3, 2
• This dual approach is necessary because systemic therapy alone does not achieve adequate vitreous concentrations 4

Treatment Duration:

• Continue antifungal therapy for at least 4-6 weeks, with final duration depending on complete resolution of lesions 1

Ophthalmologic Consultation Requirements

• All patients with candidemia require dilated retinal examination by an ophthalmologist within the first week (delay until neutrophil recovery in neutropenic patients) 4
• The ophthalmologist must determine the extent of ocular infection (chorioretinitis with or without macular involvement, with or without vitritis) 4
• Treatment decisions regarding antifungals and surgical intervention should be made jointly by an ophthalmologist and infectious diseases physician 4

Prognostic Indicators

• Direct macular involvement is a poor prognostic indicator for visual acuity recovery 1, 3, 2
• Prompt treatment is essential—delayed therapy results in permanent vision loss 2, 8
• At three months post-treatment, approximately 41% of post-cataract endophthalmitis patients achieve 20/40 or better vision, and 69% achieve 20/100 or better 5
• Fungal endophthalmitis has worse visual outcomes compared to bacterial endophthalmitis 9

Critical Pitfalls to Avoid

• Never rely on subconjunctival injections alone—they are ineffective and delay appropriate intravitreal therapy 1, 3
• Do not delay vitreous/aqueous tap for cultures—obtain specimens before starting antibiotics 1, 3, 2
• Do not forget systemic antibiotics in endogenous endophthalmitis, as the eye infection is secondary to bacteremia/fungemia requiring treatment of the primary source 2, 7
• Recognize that endophthalmitis is a medical emergency requiring same-day intervention 2, 7