eMedicine Specialties > Emergency Medicine > Ophthalmology

Endophthalmitis

Author: Daniel J Egan, MD, Associate Attending Physician, Department of Emergency Medicine, St Luke's Roosevelt Hospital Center
Coauthor(s): Jessica Radin Peters, MD, Attending Physician, Department of Emergency Medicine, Instructor, Harvard Medical School, Brigham and Women's Hospital; David A Peak, MD, Assistant Residency Director of Harvard Affiliated Emergency Medicine Residency, Attending Physician, Massachusetts General Hospital; Consulting Staff, Department of Hyperbaric Medicine, Massachusetts Eye and Ear Infirmary
Contributor Information and Disclosures

Updated: Apr 23, 2009

Introduction

Background

Endophthalmitis is an inflammatory condition of the intraocular cavities (ie, the aqueous or vitreous humor) usually caused by infection. Noninfectious (sterile) endophthalmitis may result from various causes such as retained native lens material after an operation or from toxic agents. Panophthalmitis is inflammation of all coats of the eye including intraocular structures.

Pathophysiology

Under normal circumstances, the blood-ocular barrier provides a natural resistance against invading organisms.

In endogenous endophthalmitis, blood-borne organisms (seen in patients who are bacteremic in situations such as endocarditis) permeate the blood-ocular barrier either by direct invasion (eg, septic emboli) or by changes in vascular endothelium caused by substrates released during infection. Destruction of intraocular tissues may be due to direct invasion by the organism and/or from inflammatory mediators of the immune response.

Endophthalmitis may be as subtle as white nodules on the lens capsule, iris, retina, or choroid. It can also be as ubiquitous as inflammation of all the ocular tissues, leading to a globe full of purulent exudate. In addition, inflammation can spread to involve the orbital soft tissue.

Any surgical procedure that disrupts the integrity of the globe can lead to exogenous endophthalmitis (eg, cataract, glaucoma, retinal, radial keratotomy).

Frequency

United States

Endogenous endophthalmitis is rare, occurring in only 2-15% of all cases of endophthalmitis. Average annual incidence is about 5 per 10,000 hospitalized patients. In unilateral cases, the right eye is twice as likely to become infected as the left eye, probably because of its more proximal location to direct arterial blood flow from the right innominate artery to the right carotid artery. Since 1980, candidal infections reported in IV drug users have increased. The number of people at risk may be increasing because of the spread of AIDS, more frequent use of immunosuppressive agents, and more invasive procedures (eg, bone marrow transplantation).

Most cases of exogenous endophthalmitis (about 60%) occur after intraocular surgery. When surgery is implicated in the cause, endophthalmitis usually begins within 1 week after surgery. In the United States, postcataract endophthalmitis is the most common form, with approximately 0.1-0.3% of operations having this complication, which has increased over the last 3 years.¹ Although this is a small percentage, large numbers of cataract operations are performed each year making the chances that physicians may encounter this infection higher.

Posttraumatic endophthalmitis occurs in 4-13% of all penetrating ocular injuries. Incidence of endophthalmitis with perforating injuries in rural settings is higher when compared with nonrural settings.² Delay in the repair of a penetrating globe injury is correlated with increased risk of developing endophthalmitis.³ Incidence of endophthalmitis with retained intraocular foreign bodies is 7-31%.

Mortality/Morbidity

• Decreased vision and permanent loss of vision are common complications of endophthalmitis. Patients may require enucleation to eradicate a blind and painful eye.
• Mortality is related to the patient's comorbidities and the underlying medical problem, especially when considering the etiology of hematogenous spread in endogenous infections.

Age

An association appears to exist between the development of endophthalmitis in cataract surgery and age greater than or equal to 85 years.⁴

Clinical

History

History should be focused toward practices or procedures that would increase risk of endogenous or exogenous endophthalmitis (eg, intravenous drug use, other risks for sepsis or endocarditis, recent invasive ophthalmologic procedure). See discussion below in Causes.

• Bacterial endophthalmitis usually presents acutely with pain, redness, lid swelling, and decreased visual acuity. Also, some bacteria (eg, Propionibacterium acnes) may cause chronic inflammation with mild symptoms. This organism is typical skin flora and usually is inoculated at the time of intraocular surgery.
• Fungal endophthalmitis may present with an indolent course over days to weeks. Symptoms are often blurred vision, pain, and decreased visual acuity. A history of penetrating injury with a plant substance or soil-contaminated foreign body may often be elicited.
• Individuals with candidal infection may present with high fever, followed several days later by ocular symptoms. Persistent fever of unknown origin (FUO) may be associated with an occult retinochoroidal fungal infiltrate.
• History of ocular surgery, ocular trauma, hammering steel with steel, working with baling wire, or working in an industrial setting may be elicited.
• In cases of postsurgical endophthalmitis, infection most often occurs shortly after surgery (eg, in the first week) but may occur months or years later as in the case of P acnes.
• Symptoms
  • Visual symptoms in any hospitalized patient or patient taking immunosuppressive therapy
  • Visual loss
  • Eye pain and irritation
  • Headache
  • Photophobia
  • Ocular discharge
  • Intense ocular and periocular inflammation
  • Injected eye

Physical

Physical findings correlate with structures involved and degree of infection or inflammation. A thorough eye examination should be performed to include acuity, external examination, funduscopic examination, and slit lamp examination. Seek signs of uveitis and other findings as described below. Emergent referral to an ophthalmologist for further evaluation, including more exhaustive physical examination, is indicated if endophthalmitis is seriously considered.

• Eyelid swelling and erythema
• Injected conjunctiva and sclera
• Hypopyon (layering of inflammatory cells and exudate [pus] in the anterior chamber)
• Vitreitis
• Chemosis
• Reduced or absent red reflex
• Proptosis (a late finding in panophthalmitis)
• Papillitis
• Cotton-wool spots
• Corneal edema and infection
• White lesions in the choroid and retina
• Chronic uveitis
• Vitreal mass and debris
• Purulent discharge
• Fever
• Cells and flare in the anterior chamber on slit lamp examination
• Note: Absence of pain and hypopyon do not rule out endophthalmitis, particularly in the chronic indolent form of P acnes infection.

In cases of endogenous endophthalmitis, the emergency physician needs to further evaluate the patient for the underlying source of infection.

Causes

In most clinical series, gram-positive organisms are the most common causative organisms of endophthalmitis. The most common organisms are coagulase-negative Staphylococcus epidermidis, Staphylococcus aureus, and Streptococcus species. Gram-negative organisms like Pseudomonas, Escherichia coli, and Enterococcus are observed in penetrating injuries. However, when endogenous endophthalmitis is considered alone, the percentage of bacterial organisms drops markedly because of a greater proportion of fungal infections.⁵

• Endogenous endophthalmitis
  • Individuals at risk for developing endogenous endophthalmitis usually have comorbidities that predispose them to infection.⁵ These include conditions such as diabetes mellitus, chronic renal failure, cardiac valvular disorders, systemic lupus erythematosus, AIDS, leukemia, gastrointestinal malignancies, neutropenia, lymphoma, alcoholic hepatitis, and bone marrow transplantation.
  • Invasive procedures, which may result in bacteremia, such as hemodialysis, bladder catheterization, gastrointestinal endoscopy, total parenteral nutrition, chemotherapy, and dental procedures, also can lead to endophthalmitis.
  • Recent nonocular trauma or surgery, prosthetic heart valves, immunosuppression, and intravenous drug abuse may predispose to endogenous endophthalmitis.
  • Sources for endophthalmitis include meningitis, endocarditis, urinary tract infection, and wound infection. Additionally, pharyngitis, pulmonary infection, septic arthritis, pyelonephritis, and intra-abdominal abscess also have been implicated as sources of infection.
  • Fungal organisms can occur in up to 50% of all cases of endogenous endophthalmitis.⁵ Candida albicans is by far the most frequent cause (75-80% of fungal cases). Aspergillosis is the second most common cause of fungal endophthalmitis, especially in IV drug users. Less frequent are other candidal species and Torulopsis, Sporotrichum, Cryptococcus, Coccidioides, and Mucor species.
  • The single most commonly involved gram positive organism is S. aureus, which often is implicated with skin infections or chronic systemic disease, such as diabetes mellitus or renal failure. Streptococcal species including Streptococcus pneumoniae, Streptococcus viridans, and group A streptococci also are common. Other streptococcal species, eg, group B in newborns with meningitis or group G in elderly patients with wound infections or malignancies, also have been isolated. Bacillus cereus has been implicated in intravenous drug abuse and intravenous injections. Clostridium species have been implicated in association with bowel carcinomas.
  • Gram-negative bacteria are other bacterial etiologies. E coli is the most common among the gram-negative bacteria. Haemophilus influenzae, Neisseria meningitidis, Klebsiella pneumoniae, Serratia species, and Pseudomonas aeruginosa also can cause endogenous endophthalmitis.
  • Nocardia asteroides, Actinomyces species, and Mycobacterium tuberculosis are acid-fast bacteria that may cause endogenous endophthalmitis.
• Exogenous endophthalmitis
  • Organisms that reside at the conjunctiva, eyelid, or eyelashes and are introduced at the time of surgery usually cause postoperative endophthalmitis.
  • Most cases of exogenous endophthalmitis develop postoperatively or after trauma to the eye. In fact, postoperative endophthalmitis is the most common cause of the disease. Of these cases, gram-positive organisms account for almost 90% of cases, of which the majority are coagulase-negative Staphylococcus from the natural conjunctival flora.⁶
  • The single most common cause of exogenous endophthalmitis is S epidermidis, which is a normal flora of the skin and conjunctiva. Other common gram-positive bacteria are S aureus and streptococcal species.
  • The most common gram-negative organisms associated with postoperative endophthalmitis are P aeruginosa and Proteus and Haemophilus species.
  • Although very rare, many different fungi have caused postoperative endophthalmitis, including Candida, Aspergillus, and Penicillium species.
• Traumatic endophthalmitis
  • Bacteria or fungi are introduced at the time of injury. Endophthalmitis can occur in up to 13% of cases of penetrating injury to the globe. Since penetrating trauma usually occurs in a nonsterile environment, most objects that strike the eye are contaminated with multiple infectious agents.
  • The risk of developing traumatic endophthalmitis by foreign objects carrying soil or vegetable matter is highest in rural settings. Staphylococcal, streptococcal, and Bacillus species usually cause traumatic endophthalmitis.⁷ B cereus causes much more infections in the traumatic population than in either of the other two groups, and can cause serious infection.⁸ A history of penetrating trauma with intraocular foreign body contaminated with organic matter implicates Bacillus species.⁹
  • Patients with larger lacerations, delay in time to repair of open globe, and those with more virulent organisms tend to do worse than patients with traumatic etiology.¹⁰

• Search for CME/CE on This Topic »

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• Endophthalmitis, Bacterial (Ophthalmology)
• Endophthalmitis, Fungal (Ophthalmology)
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