Endophthalmitis

Endophthalmitis is a rare, potentially sight-threatening inflammation of the vitreous humor (vitritis) that may be infectious (bacterial/fungal infection) or noninfectious (sterile). Infectious endophthalmitis can have either an exogenous (following ocular surgery/penetrating trauma) or endogenous (hematogenous spread) etiology. Staphylococcal/streptococcal infection after cataract surgery is the most common cause of exogenous bacterial endophthalmitis. Fungal endophthalmitis is often caused by Candida and is more common in immunocompromised individuals. Endophthalmitis may present either acutely with sudden, deep ocular pain and rapidly progressive loss of vision or indolently (chronic endophthalmitis). Clinical features include conjunctival hyperemia, corneal haziness, hypopyon, and decreased visual acuity. Vitreous infiltrates are seen on slit lamp examination. Diagnosis is often clear on history and ocular examination. In doubtful cases, ultrasound of the eye and gram stain and culture of the vitreous humor is indicated. Infectious endophthalmitis is treated with intravitreal injection of either antibiotics (vancomycin with ceftazidime/amikacin) or antifungals (amphotericin B/voriconazole). Surgical removal of the vitreous humor (vitrectomy) is done in sight-threatening cases. Patients with noninfectious endophthalmitis usually resolve completely with topical steroids alone. Untreated infectious endophthalmitis can progress to cause panophthalmitis, corneal rupture, and permanent vision loss.

Infectious endophthalmitis

• Causative organism
  • Bacteria: coagulase-negative staphylococci (most common), S. aureus, streptococci, B. cereus (in posttraumatic endophthalmitis)
  • Fungi: Candida (most common), mold (Aspergillus, Mucor, and Fusarium species)
• Route of entry
  • Exogenous (direct inoculation)
    • Intraocular surgeries/injections
      • Postcataract surgery (most common cause of postoperative endophthalmitis)
      • After glaucoma surgery; corneal transplant; intravitreal injections
    • Penetrating trauma (less common)
  • Endogenous (hematogenous spread)
    • Presence of a distant infectious focus → bacteremia/fungemia → seeding of the vascular choroid by the organism → spread of infection to the retina and vitreous

Noninfectious endophthalmitis (sterile)

• An inflammatory reaction to drugs injected into the vitreous
• Usually resolves completely without intravitreal antibiotics/vitrectomy

References:^{[1][2][3][4][5]}

Slit lamp examination of the eye

• Indicated in all patients with endophthalmitis.
• Cornea: edematous/hazy
• Chambers containing aqueous humor: hazy; hypopyon
• Vitreous chamber; : inflammation (cells and protein); white and fluffy infiltrates (snowball appearance) in fungal endophthalmitis

Fundoscopy

• Indicated in all patients with endophthalmitis.
• Loss of the red reflex (due to chorioretinitis)
• Roth spots; may be seen in patients with endogenous endophthalmitis due to infective endocarditis, and occasionally in fungal endophthalmitis.
• Bacterial endophthalmitis: nonvisualization of retinal vessels
• Fungal endophthalmitis: creamy white retinal nodules

Ultrasound of the eye (B-scan)

• Indicated if the vitreous cannot be seen on slit lamp examination (e.g., due to a hazy cornea/aqueous chamber)
• Findings: hyperechogenicity of the vitreous (due to inflammation), thickened chorioretinal membrane

Gram-stain and culture of aqueous and/or vitreous humor

• The aqueous and/or vitreous humor can be extracted through a fine needle and cultured.
• Indicated in doubtful cases

Workup for primary source of infection

• For patients with endogenous endophthalmitis
• Blood cultures: should be done in all patients with endogenous endophthalmitis
• When an infectious source is unknown, the following tests are indicated:
  • Urine culture to rule out UTI
  • ECHO to rule out infective endocarditis (suspect in IV drug abusers or patients with prosthetic heart valves)
  • Abdominal USG to rule out liver abscess (suspect in patients with DM, hepatobiliary disease).

References:^{[1][6][7][8][9][10][11][12]}

• Intravitreal drug administration
  • Bacterial endophthalmitis: empirical intravitreal antibiotic administration in all cases (vancomycin and ceftazidime/amikacin)
  • Mold endophthalmitis; or sight-threatening candida endophthalmitis: intravitreal antifungal administration (amphotericin B or voriconazole)
• Systemic antifungal administration (IV fluconazole or voriconazole): early disease due to Candida, all patients with endogenous fungal endophthalmitis
• Pars plana vitrectomy: in patients with sight-threatening endophthalmitis
• Sterile endophthalmitis
  • Mild/early disease: topical steroids
  • Severe inflammation: treat as bacterial endophthalmitis

Early initiation of treatment (within hours) is critical to preserve eyesight.References:^{[13][14][15][16][17]}

• Panophthalmitis
• Corneal perforation
• Phthisis bulbi
• Glaucoma
• Permanent loss of vision

References:^[18][19]

We list the most important complications. The selection is not exhaustive.