Differential Diagnosis of Endophthalmitis

, Nidhi Relhan Batra1, Stephen G. Schwartz2 and Andrzej Grzybowski3, 4

Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida, USA

Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Naples, Florida, USA

Chair of Ophthalmology, University of Warmia and Mazury, Olsztyn, Poland

Institute for Research in Ophthalmology, Poznan, Poland


Endophthalmitis is a clinical diagnosis, confirmed with subsequent laboratory testing. Endophthalmitis must be distinguished from noninfectious inflammation as well as noninflammatory cellular infiltration, including hemorrhage and tumor cells. Endophthalmitis with negative intraocular cultures is relatively common, reported in the range of about 20% following intraocular surgery and up to 50% following intravitreal injection.

It is important to consider the various conditions which may mimic as infectious endophthalmitis. The following are some conditions which should be differentiated from infectious endophthalmitis:

  1. (a)

    Toxic anterior segment syndrome (TASS)


  2. (b)

    Retained lens material


  3. (c)

    Flare-up of preexisting uveitis


  4. (d)

    Chronic vitreous hemorrhage


  5. (e)

    Retinoblastoma (in children)


  6. (f)

    Retained triamcinolone acetonide


  7. (g)

    Viral retinitis


  8. (h)

    Pseudoendophthalmitis from intravitreal injections


Toxic Anterior Segment Syndrome (Fig. 2.1)

Toxic anterior segment syndrome (TASS) is an acute postoperative sterile inflammation of the anterior segment which occurs due to toxic effects on corneal endothelium (Fig. 2.1). The following are characteristic features of TASS:

  • Usually identified on the first day following cataract surgery—Symptoms of TASS characteristically appear 12–48 h after the surgery.

  • Prominent corneal edema is observed from limbus to limbus—Corneal edema with limbus to limbus involvement is noted in most cases. Inflammation in the anterior segment is severe with fibrinous reaction.

  • Prominent anterior chamber cells (usually without hypopyon)—The inflammation usually does not involve the vitreous.


Figure 2.1
Toxic anterior segment syndrome (TASS) with limbus to limbus corneal edema

The most common symptom of TASS is blurred vision. Patients may present with blurred vision and mild pain on the same day of the surgery or within 24 hours after the surgery. In addition, the iris may be irregular with unreactive pupil. Damage to the trabecular meshwork may result in secondary glaucoma. Differentiating features between TASS and endophthalmitis are shown in the Table 2.1.

Table 2.1
Differences between toxic anterior segment syndrome (TASS) and endophthalmitis

Differences between TASS and endophthalmitis



Noninfectious reaction to toxic agent present in:

• BSS solution

• Antibiotic injection

• Endotoxin

• Residue

Bacterial, fungal, or viral infection


12–24 h

4–7 days

Signs/symptoms (*distinguishing features as reported in literature)

Blurry vision

Pain: None or mild to moderate

Corneal edema: Diffuse, limbus to limbus*

Pupil: Dilated, irregular, nonreactive*, increased IOP*

Anterior chamber: Mild to severe reaction with cells, flare, hypopyon, fibrin

Signs and symptoms are limited to anterior chamber*

Gram stain and culture negative

Decreased VA

Pain (25% have no pain), lid swelling with edema

Conjunctival injection, hyperemia

Anterior chamber: Marked inflammatory response with hypopyon

Inflammation in entire ocular cavity*—vitreous involvement present


Rule out infection

Daily observation

Intensive corticosteroids

Monitor IOP closely for signs of damage to trabecular meshwork and side effects of steroids

Culture anterior chamber and vitreous fluid

Intravitreal and topical antibiotics

Vitrectomy in selected cases

TASS can be treated with frequent administration of topical steroids. Toxic substances which have been shown in studies to cause damage to corneal endothelial cells are preoperative disinfectant, intraocular irrigating solution, highly concentrated intraocular medicine, preservatives, remnants of cleaning solutions for surgical devices, hydrogen peroxide, or the insertion of air into the anterior segment.

References: Toxic Anterior Segment Syndrome (TASS)

  • American Society of C, Refractive S, American Society of Ophthalmic Registered N. Recommended practices for cleaning and sterilizing intraocular surgical instruments. Insight. 2007;32(2):22–8.

  • Arslan OS, Tunc Z, Ucar D, Seckin I, Cicik E, Kalem H, et al. Histologic findings of corneal buttons in decompensated corneas with toxic anterior segment syndrome after cataract surgery. Cornea. 2013;32(10):1387–90.

  • Davis, Brandon L, and Mamalis N. “Averting TASS: analyzing the cause of sterile postoperative endophthalmitis provides valuable clues for its prevention”. Cataract & Refractive Surgery Today, February 2003:25-27. Eydelman MB, Tarver ME, Calogero D, Buchen SY, Alexander KY. The Food and Drug Administration’s Proactive toxic anterior segment syndrome Program. Ophthalmology. 2012;119(7):1297–302.

  • Gottsch JD, Schein OD. Taking TASS to task. Ophthalmology. 2012;119(7):1295–6.

  • Mamalis N. Toxic anterior segment syndrome update. J Cataract Refract Surg. 2010;36(7):1067–8

  • Mamalis N, Edelhauser HF, Dawson DG, Chew J, LeBoyer RM, Werner L. Toxic anterior segment syndrome. J Cataract Refract Surg. 2006;32(2):324–33.

  • Menke AM. Endophthalmitis and TASS: claims results and lessons. Ophthalmic Risk Management Digest. https://​www.​aao.​org/​asset.​axd?​ID=​dc1f5f0f-b794-4fa7-b59b-953d0f0bb261.

  • Monson MC, Mamalis N, Olson RJ. Toxic anterior segment inflammation following cataract surgery. J Cataract Refract Surg. 1992;18(2):184–9.

  • Ronge LJ. Toxic anterior segment syndrome: why sterile isn’t clean enough. EyeNet. 2002:17–18.

Retained Lens Fragments (Figs. 2.2 and 2.3)

Patients with retained lens fragments after cataract surgery may develop marked intraocular inflammation with hypopyon in the absence of infection (Figs. 2.2 and 2.3). However, concomitant endophthalmitis also may be present and it is important to make the correct diagnosis. It is possible that the eyes with retained lens fragments may be at increased risk for endophthalmitis. Neither the presence of pain nor the duration of time after surgery are absolute differentiating points between retained lens fragments and endophthalmitis.
Jan 14, 2018 | Posted by in OPHTHALMOLOGY | Comments Off on Differential Diagnosis of Endophthalmitis

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