Clinical Indications of Endophthalmitis
Endophthalmitis presents with the triad of ocular pain, decreased vision, and inflammatory findings (particularly hypopyon), and should be treated as a vision-threatening emergency requiring immediate ophthalmology consultation. 1
Key Clinical Presentations
Cardinal Symptoms
- Acute visual changes with rapid onset of decreased vision or vision loss 1, 2
- Severe ocular pain that is often excruciating and out of proportion to examination findings 1, 2
- Inflammatory signs including hypopyon (layered white blood cells in the anterior chamber), which is highly suggestive of endophthalmitis 1
Physical Examination Findings
- Vitreous inflammation with surge of inflammatory cells in the vitreous space, visible on ophthalmoscopic examination 3, 4
- Redness and conjunctival injection of the affected eye 4
- Purulent discharge in some cases, particularly with more virulent organisms 4
- Fever may be present in endogenous endophthalmitis from hematogenous spread, but is typically absent in exogenous (post-surgical or traumatic) cases 2
Risk Factors That Should Raise Suspicion
Exogenous Sources (Most Common)
- Recent ocular surgery, particularly cataract surgery where coagulase-negative staphylococci predominate 5, 6
- Penetrating ocular trauma with environmental organisms like Bacillus cereus, Pseudomonas aeruginosa, or environmental mycobacteria 5, 6
- Intravitreal anti-VEGF injections with increasing incidence, typically caused by coagulase-negative staphylococci or viridans streptococci 6
- Corneal transplantation where endophthalmitis is a rare but devastating complication 5
Endogenous Sources (Hematogenous Spread)
- Active candidemia - the Infectious Diseases Society of America mandates dilated retinal examination within the first week of therapy for all candidemia patients 7, 8
- Injection drug use with hematogenous dissemination of organisms 5
- Immunocompromised state including patients with prolonged hospitalization and indwelling catheters 7
- Diabetes mellitus as a predisposing condition 1
- Bacterial endocarditis, particularly with Staphylococcus aureus and streptococci 6
Diagnostic Approach
Essential Diagnostic Steps
- Direct ophthalmoscopic examination is required for definitive clinical diagnosis 3
- Culture of vitreous or aqueous humor via diagnostic vitreous tap before initiating treatment to identify the causative organism 3
- Imaging modalities (CT, MRI, ultrasound) may suggest endophthalmitis but cannot exclude the diagnosis - clinical evaluation remains paramount 1
Common Pitfall to Avoid
Do not delay treatment waiting for imaging confirmation. The diagnosis is clinical, and acute bacterial endophthalmitis is a medical emergency where delay results in permanent vision loss 2. Imaging serves only as an adjunct when the diagnosis is uncertain.
Organism-Specific Patterns
Post-Surgical Endophthalmitis
- Coagulase-negative staphylococci (68.4%) and Streptococcus species (8.2%) dominate after cataract surgery 5
- Do not dismiss Propionibacterium acnes as a contaminant in chronic post-operative cases - it is a true pathogen in this setting 5
Fungal Endophthalmitis
- Candida species (particularly C. albicans) in hospitalized patients with candidemia 7, 8, 6
- Aspergillus species in immunocompromised patients, injection drug users, or those with disseminated aspergillosis 5, 8
- Environmental fungi (Fusarium, dematiaceous fungi) after trauma 5
Geographic Considerations
- In Taiwan and East Asia, Klebsiella pneumoniae causes most endogenous endophthalmitis cases, typically associated with liver abscess 6