Phacoanaphylactic Endophthalmitis

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Article initiated by:

Cooper D. Rodgers, MD, Thomas King

All contributors:

Ghazala D. O'Keefe, MD, Leo A. Kim, MD, PhD, Jennifer Cao, MD, Cooper D. Rodgers, MD

Assigned editor:

Jennifer Cao, MD, Mark P. Breazzano, MD, FACS

Review:

Assigned status Up to Date

 by Jennifer Cao, MD on November 13, 2024.

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Contributing Editors:	add

Disease Entity

ICD 10 code: H44.19

Endophthalmitis: other

Disease

Lens-induced uveitis (LIU) is an uncommon autoinflammatory condition where the immune system’s natural tolerance of lens protein is abandoned, most often occurring after traumatic or surgical lens injury. This disease is also known by other names including phacoanaphylactic endophthalmitis, phacogenic uveitis, and phacotoxic uveitis. It was first described in medical literature in 1919 and termed “endophthalmitis anaphylactica” in a 1922 case series of patients who developed non-infectious endophthalmitis days to weeks following extracapsular cataract surgery. Contrary to what is suggested by such a name, this disease does not involve true anaphylaxis and does not feature an IgE-mediated response. LIU remains a small fraction of clinically encountered cases of uveitis, especially with modern surgical techniques that include complete removal of the lens during cataract removal.

Etiology

LIU is thought to be the result of an abnormal immune tolerance to lens proteins, resulting in a cell-mediated autoimmune phenomenon. Researchers have argued against the mechanism of immune privilege and rejection of newly encountered self antigens, noting the rare frequency of this condition despite the presence of extracapsular lens protein in asymptomatic individuals. Instead, this condition is proposed to be caused by an abnormal recognition of self antigens on lens material.

Risk Factors

Violation of the lens capsule during trauma or surgery is a known risk factor for LIU. Patients with hypermature cataracts are also at an increased risk of developing this condition as degrading lens material is known to leak through an intact capsule, triggering an autoinflammatory response. The primary affected demographic is 50-79 years of age, however younger patients can also be affected.

Pathophysiology

The pathophysiology of this disease begins with the introduction of the lens protein to the immune system. While this can be the result of traumatic or surgical injury to the lens or surrounding lens capsule, these proteins may also come into contact with the extracapsular space due to leakage through the capsule in advanced cataracts in the absence of trauma to the lens. In post-operative cases, retained cortical fragments may also trigger an autoinflammatory state.

Despite the name phacoanaphylactic endophthalmitis, this disease is not an IgE mediated response. Rather, it involves an immune complex-mediated mechanism that is proposed to follow the loss of T-cell tolerance of lens proteins. This will classically result in a granulomatous reaction mediated by monocytes and polymorphonuclear cells to lens protein. This process can involve a type II, III, or type IV hypersensitivity reaction. Clinical symptoms typically emerge between days to months following the inciting event and can range from mild to very severe endophthalmitis.

Epidemiology

There is a paucity of data on the incidence and prevalence of this rare condition. One study in a Korean population reported that LIU represented 0.4% of all cases of uveitis.

History

Evaluation for LIU should include a history with attention to recent ocular trauma or surgery on the affected eye. While this condition is associated with a variable presentation in both latency and severity of symptoms, clinical symptoms typically emerge within two weeks of lens injury.

Symptoms

Symptoms of LIU are limited to the traumatized eye while the contralateral eye is spared. Symptoms typically include decreased vision, photophobia, conjunctival injection, and pain. The onset of symptoms may range from gradual to acute.

Signs

Slit-lamp examination of a patient with LIU may reveal lens fragments in the anterior chamber, corneal edema, anterior chamber cell and flare, keratic precipitates, and hypopyon. There may or may not be a disturbance in visual acuity or intraocular pressure, given the highly variable presentation of this disease.^,

Diagnostic procedures

Although LIU can be diagnosed clinically based on a careful history and slit-lamp examination, in practice, most cases require one or more diagnostic tests to be certain of the diagnosis. Scanning electron microscopy or anterior segment optical coherence tomography (OCT) may be useful for detailed examination of the lens capsule, with evidence of capsular trauma supporting the diagnosis.

Confirmation of this disease may be achieved through needle biopsy with histopathology or cytology of the aqueous humor. Cytological examination may discover evidence of the characteristic granulomatous response including macrophages and polymorphonuclear cells surrounding lens material, which is strongly suggestive of lens-induced uveitis.

Laboratory Test

Although it is often difficult to distinguish between LIU from other classes of postoperative uveitides, it can be identified histopathologically by a zonal pattern of neutrophilic and granulomatous response with associated lens remnants. Cytology may otherwise be remarkable for elevated levels of alpha and beta crystallin.

Differential Diagnosis

Infectious endophthalmitis

Sympathetic ophthalmia

Iritis Glaucoma

Ocular tuberculosis

Uveitis

Vogt-Koyanagi-Harada (VKH) disease

General Treatment

The initial treatment strategy for lens-induced uveitis involves prompt screening for associated increased intraocular pressure by tonometry and initiation of aqueous suppressant therapy as needed. Definitive management of this condition involves removing the offending lens material.

Medical Therapy

Medical therapy in the preoperative period should aim to control intraocular pressure. This can be achieved with aqueous suppressants or systemic medications such as acetazolamide or mannitol if needed. Topical or systemic steroids may have a role in the treatment of LIU depending on the severity of clinical presentation. Preoperative antibiotic therapy is also recommended in LIU and may be used in cases where cataract extraction was previously performed as well as in those cases where the presumed cause of LIU is a hypermature cataract. ^,

Surgery

Surgical management is the definitive treatment for lens-induced uveitis. This is considered an emergency condition for which surgery should be performed following reduction of IOP to the physiologic range if it is elevated.

The surgical approach for LIU is tailored to the causative agent for clinical symptoms. In cases where there is a cataract present in the affected eye, cataract extraction is recommended. The technique of cataract removal, whether via lens aspiration, phacoemulsification, manual small incision cataract surgery, or extracapsular cataract extraction, should depend on patient characteristics as well as surgeon preference.

For patients with a history of cataract removal, washout of retained lens fragments is preferred. Washing of the anterior chamber is performed in cases where the posterior lens capsule is intact. If the posterior capsule has been violated and lens fragments have descended to the vitreous, pars plana vitrectomy is indicated.

Cases of lens-induced uveitis following non-cataract surgery have also been described in the literature. These include, for example, lens-induced uveitis with the onset of symptoms days following a pars plana vitrectomy complicated by injury to the posterior lens capsule during gas injection. In such cases, where lens material was displaced into the vitreous cavity, repeat pars plana vitrectomy with removal of offending lens material has resulted in favorable outcomes.

In severe cases without removal of lens fragments, severe pain and blindness in the affected eye may develop as early as one year after lens trauma. Such cases have previously been effectively treated with enucleation of the eye and insertion of an orbital implant.

Follow-Up

Postoperatively, an inspection of the posterior segment and any sutures placed intraoperatively as well as evaluation of intraocular pressure should be performed. Antiglaucoma medications, as well as steroid treatment, may be required to manage residual symptoms in the early postoperative period. In the case of traumatic lens rupture, patient education on best safety practices is also recommended.

Complications

Lens-induced uveitis may be complicated by glaucoma in over 50% of cases, which is proposed to result from obstruction of the trabecular meshwork by inflammatory cells and lens fragments. The chronic inflammation may further disrupt the flow of the aqueous humor and result in angle-closure glaucoma due to the formation of peripheral anterior synechiae.

Lens fragments as well as intraoperative manipulation for cataract surgery also contribute to corneal edema, which may be present in a majority of cases postoperatively.^,

In addition, aggressive attempts at removal of lens fragments via vitrectomy have been complicated by giant retinal tear in several cases.The incidence of retinal detachment has been reported to be 9% following pars plana vitrectomy.

Prognosis

Given that lens-induced uveitis is relatively rare and presents with variable signs and symptoms, it can be difficult to diagnose and treat promptly. The clinical course of illness may also be lengthened in rural communities with limited access to treatment for early cataract removal. Among patients with late presentations of disease associated with hypermature cataracts, over half of patients may not achieve visual acuity of greater than 6/60, which may be attributable to chronic pathologic changes including optic disc atrophy and corneal edema.^, However, other reports describe a return to visual acuity of at least 6/12 in nearly 80% of patients following manual small incision cataract surgery (MSICS).

In patients undergoing vitrectomy for lens fragment retrieval, greater than 60% of patients may achieve final visual acuity of 20/40 or better.