ENDOPHTHALMITIS

JAGDISH DUKRE

Endophthalmitis is defined as an intra-ocular inflammation which predominantly affects the inner spaces of the eye and their contents i.e. the vitreous and/or the anterior chamber.

DEFINITION

A. Exogenous

1. Postsurgicala. Acute onsetb. Delayed onset

c. Bleb associated

2. Nonsurgicala. Post-traumatic

B. Endogenous

CLASSIFICATION OF ENDOPHTHALMITIS

A. Exogenous Acute onset Postsurgical Gram positive : S. epidermidis, S. aureus , Streptococcus spp.

Gram negative : Pseudomonas, Proteus,

H. influenzae, Klebsiella, E. coli, Enterobacter

Delayed onset Postsurgical Fungi : aspergillus, fusarium, candid, penicillum

Bacteria : P. acnes S. epidermidis

Post-traumatic : Bacillus spp. S. epidermidis Streptococcus spp.

fungi (fusarium)

B. Endogenous Bacteria : B. cereus ( IV abusers), Streptococcus spp.,

S. aureus, Meningococci , H. influenzae

Fungi : mucor, candida

Common organisms causing endophthalmitis

Depending on the infecting organism, there is a correlation a between clinical presentation and microbiologic spectrum.

Gram-positive, coagulase-negative micrococci cause less severe infections compared with more virulent Gram-negative and “other” Gram-positive organisms.

Streptococcal endophthalmitis often results in earlier onset and notably worse outcomes than infections by staphylococcal species.

If more virulent pathogens are involved then signs and symptoms appear earlier, which is significantly correlated with a worse visual outcome.

PATHOGENESISBacterial entry into eye

Cascade of inflammatory products

Inflammatory cell recruitment

Release of digestive enzymes by the cells & toxins by bacteria

Tissue destruction

Cataract surgery is by far the most frequently performed intraocular surgery.

Approximately 90% of postoperative endophthalmitis cases develop after cataract surgery.

Endophthalmitis can also complicate other ocular surgeries and procedures such as

intravitreal injections, penetrating keratoplasty, trabeculectomy and glaucoma drainage device implantation. Pars Plana Vitrectomy

Post-Surgical Endophthalmitis

Surgery Incidence

Cataract Surgery 0.08-0.7%

Pars Plana Vitrectomy 0.03-0.05%

Penetrating Keratoplasty 0.11-0.18%

Glaucoma Filtering Surgery 0.2%–9.6%

• Regarding glaucoma filtering surgery, endophthalmitis is reported to occur after 0.2%–9.6% of trabeculectomies and its incidence seems to increase with the rising use of antifibrotic agents.

• Pars plana vitrectomy with the lowest (0.03%–0.05%).

Rates of Post-Cataract Endophthalmitis

1970 1980 1990 2003-20050

0.05

0.1

0.15

0.2

0.25

0.3

0.35

Years

Inci

den

ce

• The rate of post-cataract endophthalmitis has been steadily decreasing until the end of the 1990s, when an increase in incidence was reported.• Incision type appears to be the most significant risk endophthalmitis rates following

• clear corneal cataract extraction 0.189% versus • scleral incisions 0.074% between 1992 and 2003

Duration of presentation

a. 2/3rd of patients present within a week of cataract surgery.

b. Nearly 25% within 3 days.

c. 20% of patients may present 2-6 weeks after surgery.

No. of Days post-operative

percentage

0-3 days 24 %

4-7 days 37 %

8-13 days 17 %

2-6 weeks 22 %

Acute endophthalmitis typically is defined as occurring within 6 weeks of surgery.

According to the EVS,

94.2% of culture-positive endophthalmitis cases involved Gram-positive bacteria;

70% of isolates were Gram-positive, coagulase-negative staphylococci,

9.9% were Staphylococcus aureus,

9.0% were Streptococcus species,

2.2% were Enterococcus species, and

3% were other Gram-positive species.

Gram-negative species were involved in 5.9% of cases.

In contrast, a recent survey from India reported that Gram positive bacteria accounted for only 53% of postoperative endophthalmitis

cases, but 26% were Gram-negative isolates and 17% were of fungal origin.

Acute Postoperative Endophthalmitis

Symptoms

Blurred vision (94%)

Red eye (82%)

Pain (74% )

Swollen lid (34%)

Photophobia

Purulent discharge

Blurred vision

red eye pain swollen lid0

10

20

30

40

50

60

70

80

90

100

Signs Decreased visual acuity

Lids- edema

Conjunctiva- congestion and chemosis

Cornea – edema, ring abscess (Pseudomonas and Bacillus)

Anterior chamber- cells and flarehypopyon(in 86%patients in EVS)

Iris muddy and boggy

Pupil-fibrinous exudate

IOL-may be covered by fibrin

Fundus- vitreous exudates, scattered retinal haemorrhages Periphlebitis, loss of red reflex

DELAYED ONSET INFECTIOUS ENDOPHTHALMITIS

Occurs more than 6 weeks following surgery.

Lower virulence organisms –Propionibacterium acnes,Staphylococcus aureus and fungi may be involved.

Secondary contamination after suture removal

After Nd:Yag capsulotomy due to release of sequestered organisms in the capsule.

SYMPTOMS-

Photophobia Blurred vision Mild pain

SIGNS- Keratic precipitates

in anterior chamber Vitreous flare and cells Capsular plaque

(in Propionibacterium acnes endophthalmitis after Nd:Yag capsulotomy)

Granuloma formation in the pupillary area or near the section(in fungal endophthalmitis)

BLEB ASSOCIATED INFECTIOUS ENDOPHTHALMITIS

Following glaucoma filtering surgery.

Local antimetabolite adjuncts increase the risk

May range from blebitis to frank endophthalmitis.

Most common causative organisms are streptococcus spp, and haemophilus influenzae.

Incidence of delayed bleb related endoph varies from 0.2 to 10%

Severe blebitis may cause scleral necrosis and fistula at the site of bleb.

Post-traumatic endophthalmitis

The risk for developing endophthalmitis after sustaining open globe injuries is estimated at about 7%.

Increasing risk factors for endophthalmitis after ocular injury are

dirty wound, lens capsule rupture, older age, initial presentation with a delay of more than 24 hours, and the presence of intraocular foreign bodies.

The incidence of endophthalmitis in cases of penetrating ocular trauma: 3.3% to 30% and after intraocular foreign body: 1.3% to 61%.

Bacillus and Streptococcus are common species found in penetrating trauma with an intraocular foreign body.

Other species isolated include S. epidermidis, Propionibacterium acnes, Pseudomonas and Gram-negative organisms, fungi and mixed pathogens

Bacillus species are associated with more aggressive infection and are especially common in intraocular foreign bodies with organic composition.

Initial evaluation of post-traumatic endophthalmitis must exclude occult or retained foreign bodies.

Magnetic resonance imaging must be avoided because a retained foreign body might be magnetic.

Endogenous endophthalmitis

The endogenous form of endophthalmitis accounts for approximately 5% to 10% of endophthalmitis cases.

It occurs when microorganisms in the bloodstream get into the eye, cross the blood–retina barrier, and infect the ocular tissue.

Because of the higher blood flow, choroids and ciliary body are the primary focuses of infection in the eye with secondary involvement of the retina and vitreous.

Risk factors for the development of endogenous endophthalmitis are mainly related to immunosuppression or to procedures that increase the risk for blood-borne infections.

Most common factors include immunosuppressive diseases, such as

diabetes mellitus, HIV infection, cancer, renal failure requiring dialysis, cardiac disease, long-term use of broad-spectrum antibiotics, steroids and other immunosuppressive drugs, major surgery, especially intra-abdominal surgery, indwelling intravenous catheters, and intravenous drug abuse.

Liver abscesses have been reported as the most common infectious origin, followed by pneumonia, endocarditis, soft tissue infection, urinary tract infections, meningitis, septic arthritis, and orbital cellulitis.

Causative organisms of endogenous endophthalmitis may be bacteria, as well as fungi.

In contrast to exogenous forms of this disease, in endogenous endophthalmitis fungal pathogens play an important role.

Streptococcus species, S. aureus, and other Gram-positive bacteria account for two-thirds of bacterial endogenous endophthalmitis cases and Gram negative isolates are found in only 32% of cases.

Candida albicans followed by Aspergillus are the predominant species.

Other isolates commonly found in endogenous fungal endophthalmitis are Cryptococcus and Fusarium species.

Fungal endophthalmitis

Fungal endophthalmitis manifests in a more indolent fashion, usually with the progressive infectious process only becoming evident 2 or more weeks after surgery.

Fungal endophthalmitis is characterized by a smoldering inflammatory reaction, minimal pain, and only mild external involvement, but with progressive iridocyclitis and vitreitis, which are often most pronounced at the iris-pupillary border or anterior vitreous.

Candida albicans followed by Aspergillus are the predominant species.

Candidal endophthalmitis

The two most characteristic clinical signs are

creamy white, well-circumscribed chorioretinal lesions , most common in the posterior pole, and

yellow or white fluffy vitreous opacities.

They may be connected by strands of inflammatory material, producing what has been called a string-of-pearls appearance.

These focal vitreous opacities have been shown to evolve from the chorioretinal inflammatory lesions after they have broken through into the vitreous.

These vitreous opacities are composed of inflammatory cells and often contain Candida organisms.

Aspergillus endophthalmitis

• Most patients with endogenous Aspergillus endophthalmitis have acute or subacute ocular symptoms.

• Most patients have anterior segment inflammatory signs, including anterior chamber cells ,keratic precipitates and a hypopyon may be present.

• In most cases the organism initially affects the posterior segment, forming a yellowish macular infiltrate .

• It frequently involves the macula, and this probably accounts for the rapid onset of visual loss in many cases.

A frequent clinical feature is the pseudohypopyon in either the preretinal (subhyaloid) or subretinal space .

Although this finding is not pathognomonic of Aspergillus infection, when seen it should prompt a high suspicion for Aspergillus.

This is usually associated with a vitritis.

Other features include occlusive vasculitis and retinal hemorrhages.

Orbital involvement can also occur, but this usually results from contiguous spread from an adjacent sinus infected with Aspergillus..

After treatment the area of chorioretinitis progresses to formation of a subretinal scar.

the visual outcome is generally poor.