ENDOPHTHALMITIS

Endophthalmitis refers to inflammation that may ultimately involve all tissues of the eye. Exogenous endophthalmitis occurs when trauma or surgery allows microorganisms access into the eye. Endogenous endophthalmitis occurs when microorganisms spread to the eye from another source in the body, usually via the bloodstream. Endophthalmitis is an infrequent clinical entity but has the potential to cause severe visual loss.

Symptoms

In postoperative and posttraumatic endophthalmitis, patients will notice increasing redness and decreasing vision within 1 to 7 days. Pain is usually but not necessarily present. The upper eyelid may become edematous and difficult to open. Discharge may be seen in the conjunctival cul-de-sac. In endogenous endophthalmitis, susceptible patients (eg, septic, immunocompromised, users of intravenous drugs) will notice progressively blurred vision or floaters. A chronic bacterial endophthalmitis following cataract surgery may masquerade as a chronic uveitis that occurs months to years following intraocular surgery.

Clinical Features

In exogenous endophthalmitis, ophthalmologic examination shows conjunctival injection and chemosis, variable degrees of corneal edema, anterior chamber cells, flare, fibrin, hypopyon, and heavy cellular debris in the vitreous. In endogenous endophthalmitis, examination shows vitreous cells and debris with either retinal involvement or a reduced red reflex. In chronic bacterial endophthalmitis caused by Propionibacterium acnes, a creamywhite plaque may be visible within the peripheral lens capsule.

Ancillary Testing

The clinical diagnosis is confirmed by obtaining aqueous and vitreous for culture on blood agar, chocolate agar, Sabouraud’s media or broth, and thioglycolate broth. Material is also placed on two glass slides for Gram and Giemsa stains. In post-traumatic endophthalmitis an orbital computed tomography scan is necessary to rule out an intraocular foreign body.

Pathology/Pathogenesis

Bacteria, fungi, protozoa, parasites, and viruses are all capable of producing endophthalmitis. The most common organisms causing acute bacterial endophthalmitis after cataract surgery are Staphylococcus aureus and

S epidermidis. Streptococcus pneumoniae and

Haemophilus influenzae are common causes of bacterial endophthalmitis following glaucoma filtering surgeries. In traumatic endophthalmitis, Bacillus species are frequent pathogens. Propionibacterium acnes is the most commonly recognized organism causing chronic bacterial endophthalmitis following cataract surgery.

Treatment/Prognosis

Intravitreal injection of antibiotics, with or without victrectomy, is the standard of care in endophthalmitis. Antibiotics can also be administered via systemic, periocular, and topical routes. The role of corticosteroids remains controversial. Regarding visual outcome, the most important prognostic indicator is the virulence of the infecting organism. Although the use of prophylactic antibiotics to reduce the occurrence of post-cataract surgery endophthalmitis is controversial, most surgeons recommend using preoperative povidone-iodine antisepsis.

Systemic Evaluation

Systemic evaluation is generally not necessary for exogenous endophthalmitis. For endogenous endophthalmitis, an aggressive search for the systemic source of infection is indicated, including cultures of the blood, urine, indwelling catheters, and intravenous lines. Involvement of an infectious disease specialist or internist is essential.

Acute bacterial endophthalmitis following cataract surgery is characterized by conjunctival injection and chemosis, corneal edema, anterior chamber cell and flare, and hypopyon. The degree of pain is variable.

Endophthalmitis may develop in patients following glaucoma filtering surgery, with or without the use of topical antimetabolites. Common bacteria include

Streptococcus pneumoniae and Haemophilus influenzae.

Some patients with acute bacterial endophthalmitis have fibrin in the pupil in addition to the hypopyon. Common organisms include Staphylococcus aureus and

S epidermidis.

This patient developed endophthalmitis following a penetrating corneal injury. Bacillus species are common causes of traumatic endophthalmitis.

Propionibacterium acnes is the most commonly recognized organism causing chronic bacterial endophthalmitis following cataract surgery. P acnes endophthalmitis may mimic chronic uveitis.

Retroillumination of the same eye reveals the shadow of a capsular plaque in the 9 o’clock position. The patient responded well to pars plana vitrectomy and intraocular vancomycin.

Human immunodeficiency virus (HIV) is a retrovirus implicated in the development of acquired immunodeficiency syndrome (AIDS). Infection of helper T cells results in a profound disruption of the cell-mediated immune system. Immunodeficiency leads to susceptibility to blinding infections.

Symptoms

Pathology/Pathogenesis

Cotton wool spots result from microinfarction of the nerve fiber layer. Arteriolar deposition of immunoglobulin in the microvasculature around the cotton wool spots suggests an immune complex disease. Attempts to isolate organisms from cotton wool spots have been unsuccessful.

Noninfectious retinopathy is generally asymptomatic. Symptomatic disease is most often secondary to infectious disease occurring with the development of AIDS.

Clinical Features

The most common finding is a noninfectious retinopathy characterized by cotton wool spots, retinal hemorrhages, and microvascular disease. The noninfectious retinopathy does not correlate with the clinical severity of HIV disease. Chorioretinal infectious disease associated with AIDS includes cytomegalovirus retinitis, toxoplasmosis,

Mycobacterium avium-intracellulare choroiditis, cryptococcus choroiditis, and Pneumocystis carinii choroiditis.

Ancillary Testing

Human immunodeficiency virus retinopathy does not require other testing.

Treatment/Prognosis

Noninfectious HIV retinopathy does not require treatment. While some investigators have speculated that cotton wool spots may represent P carinii infection or early cytomegalovirus retinopathy, patients with noninfectious HIV retinopathy should not be subjected to toxic medications. Infectious retinopathy must be aggressively treated.

Systemic Evaluation

The diagnosis of HIV must be considered in patients with unexplained cotton wool spots or intraretinal hemorrhages. Patients with HIV disease or AIDS must be followed up closely by internists or infectious disease specialists for the many systemic diseases associated with immunodeficiency.

Fundus photograph of a 39-year-old man with human immunodeficiency virus (HIV) disease reveals numerous cotton wool spots and intraretinal hemorrhages characteristic of HIV retinopathy.

Cytomegalovirus retinitis is the most common opportunistic ocular infection in patients with acquired immunodeficiency syndrome. Cytomegalovirus retinitis is characterized by full-thickness retinitis and intraretinal hemorrhage.

Higher-magnification view of same patient reveals cotton wool spots and intraretinal hemorrhages. A few of the intraretinal hemorrhages have white centers.

Patients with acquired immunodeficiency syndrome may develop toxoplasmosis retinochoroiditis. The extent of vitritis is low because of the immunodeficiency. Patients may develop diffuse infection with acute retinal necrosis.

Pneumocystis carinii choroiditis was seen in patients with acquired immunodeficiency syndrome before the use of systemic therapy. Patients were usually asymptomatic in spite of the dramatic appearance of the choroidal lesions.

Progressive outer retinal necrosis is a form of acute retinal necrosis seen in patients with acquired immunodeficiency syndrome. It is characterized by full-thickness retinitis without evidence of intraocular inflammation or vasculitis.