Infectious endophthalmitis

Exogenous acute postoperative endophthalmitis is the most common type. Acute endophthalmitis is defined when it occurs less than six weeks after intraocular surgery (including intravitreal injections). Patients represent with blurry vision (94.3%), redness of the eye (82%), and pain (74%), according to the endophthalmitis vitrectomy study (EVS).11 Then, patients may have photophobia and epiphora According to the Endophthalmitis Vitrectomy Study (EVS) (11), most patients, precisely 94.3%, experienced blurry vision as a symptom. Other common symptoms reported were eye redness, affecting 82% of patients, and pain, experienced by 74%. In addition to these primary symptoms, patients may exhibit photophobia (sensitivity to light) and epiphora (excessive tearing).

Suspect endophthalmitis in any eye with inflammation greater than a usual postoperative course Always evaluate whether there is a wound leak or dehiscence, suture abscesses, vitreous incarceration in the wound, exposed tube shunt, or eroding scleral sutures.

The EVS gave the standard criteria to evaluate visual acuity in endophthalmitis:

If no letters could be read on the (ETDRS) chart at 4 m, then at 1 m, the vision was tested for the ability to count fingers. If the patient could not count fingers, the vision was tested for recognizing hand motions. For this, the patient’s opposite eye was occluded. A light source, such as a lamp used for near vision, was directed from behind the patient to the examiner’s hand that either was stationary or was moved at one motion per second in a horizontal or vertical direction at a distance of 60 cm from the eye. The patient was asked to identify whether the examiner’s hand was still, moving sideways, or moving up and down. The presentation was repeated five times, and hand-motion visual acuity was considered present if the patient could identify the examiner’s action on at least four of the presentations. If the examiner was not convinced that hand motions could be detected, LP was tested at 0.9 m with an indirect ophthalmoscope set at maximum intensity.(11)

Remember to take a good medical history. Sometimes endophthalmitis may be chronic and happen months after surgery (more than six weeks post-surgery). In chronic cases, pain may be absent.

Hypopion (yellow abscess in the anterior chamber) is a hallmark of endophthalmitis. It is present in 85% of cases. That means that the absence of hypopyon does not rule out endophthalmitis. In chronic cases, hypopyon is not commonly present.

The conjunctiva and sclera are severely inflamed (red) with or without chemosis. Corneal oedema can occur with cells in both the anterior and posterior chambers. The optical media is hazy, and the red reflex may be missing. The eyelids are often swollen. The retina is not usually well seen due to inflammatory debris in the vitreous. Nonetheless, you can notice cotton wool spots, chorioretinal lesions, and optic disc oedema.

A distinct white intracapsular plaque is commonly observed in cases of chronic endophthalmitis caused by Propionibacterium acne. Additionally, large granulomatous precipitates can be seen in the cornea and the intraocular lens (IOL), resembling posterior uveitis. A characteristic finding is the presence of “fluff balls” or “pearls-on-a-string” near the capsular remnant. However, it is not exclusive to fungal infections and cannot be considered pathognomonic for such cases.

Early diagnosis and baseline visual acuity are critical for positive visual outcomes. The slit lamp findings, along with symptoms and clinical signs, are essential in making suspicion on the diagnosis. The eye liquids specimens are crucial in confirming the diagnosis. Both vitreous samples and aqueous samples can be done. The EVS study showed that vitreous sampling gives more positive results.(11) A trained expert must take the sample and perform intravitreal injections with antibiotics.

Ultrasound can be a valuable and efficient tool when the optical media are hazy. The ultrasound shows diffuse vitreal opacities with or without vitreal membranes. There is the presence of chorioretinal thickening. Retinal and choroidal detachments may occur, which are poor prognostic factors.

There are two major approaches to treating exogenous endophthalmitis: vitrectomy vs tap- and-inject procedure. – The tap-and-inject procedure involves obtaining a vitreous sample and administering intravitreal antibiotic injections promptly. The current evidence is based on the results and conclusions of the Endophthalmitis Vitrectomy Study. – The study findings indicated that individuals with visual acuity of light perception or worse experienced benefits from vitrectomy. However, there was no statistically significant difference between those with hand motions vision or better between vitrectomy and the tap-and-inject procedure.(11) Some centres use the tap-and-inject procedure as first-line treatment in endophthalmitis cases. – Some experts believe that immediate vitrectomy can benefit all cases while acknowledging that (EVS) has certain restrictions. – However, it is essential to note that currently, there is a lack of substantial evidence that definitively confirms this notion.

Intravitreal antibiotics are the treatment of choice (vancomycin, ceftazidime, amikacin) in bacterial endophthalmitis. Amphotericin B or voriconazole are treatments of choice in fungal endophthalmitis. Intravenous antibiotics have a significant role in endogenous endophthalmitis. The role of corticosteroids in treating endophthalmitis is controversial and may worsen fungal endophthalmitis.