Acanthamoeba sclerokeratitis. Determining diagnostic criteria

Acanthamoeba scleral abscess reoccurring after penetrating keratoplasty

Two months following penetrating keratoplasty for Acanthamoeba keratitis, a 76-year-old man was referred due to inability to wean high-dose topical steroids. Despite a very healthy graft and minimal pain, a scleral abscess involving three clock hours of the superior conjunctiva was present. The patient underwent conjunctival and scleral excision of the area of apparent infection with adjuvant mitomycin C and double freeze-thaw cryotherapy treatment followed by amniotic membrane graft. Recurrence was confirmed with PCR. Following a multimonth regimen of oral voriconazole and topical polyhexamethylene biguanide, chlorhexidine and moxifloxacin, the patient was weaned from all anti-infectious agents. After cataract surgery and scleral lens fitting, the patient is now 20/20 in the affected eye. This case highlights the need for judicious use of immunosuppressive agents as well as the necessary vigilance to monitor for recurrence with Acanthamoeba infection. It also represents the first reported use of adjuvant mitomycin C and double freeze-thaw cryotherapy for treatment of Acanthamoeba scleral abscess.

Innate and Adaptive Gene Single Nucleotide Polymorphisms Associated With Susceptibility of Severe Inflammatory Complications in Acanthamoeba Keratitis

Purpose

Over a third of patients with Acanthamoeba keratitis (AK) experience severe inflammatory complications (SICs). This study aimed to determine if some contact lens (CL) wearers with AK were predisposed to SICs due to variations in key immune genes.

Methods

CL wearers with AK who attended Moorfields Eye Hospital were recruited prospectively between April 2013 and October 2014. SICs were defined as scleritis and/or stromal ring infiltrate. Genomic DNA was processed with an Illumina Low Input Custom Amplicon assay of 58 single nucleotide polymorphism (SNP) targets across 18 genes and tested for association in PLINK.

Results

Genomic DNA was obtained and analyzed for 105 cases of AK, 40 (38%) of whom experienced SICs. SNPs in the CXCL8 gene encoding IL-8 was significantly associated with protection from SICs (chr4: rs1126647, odds ratio [OR] = 0.3, P = 0.005, rs2227543, OR = 0.4, P = 0.007, and rs2227307, OR = 0.4, P = 0.02) after adjusting for age, sex, steroids prediagnosis, and herpes simplex keratitis (HSK) misdiagnosis. Two TLR-4 SNPs were associated with increased risk of SICs (chr9: rs4986791 and rs4986790, both OR = 6.9, P = 0.01). Th-17 associated SNPs (chr1: IL-23R rs11209026, chr2: IL-1β rs16944, and chr12: IL-22 rs1179251) were also associated with SICs.

Conclusions

The current study identifies biologically relevant genetic variants in patients with AK with SICs; IL-8 is associated with a strong neutrophil response in the cornea in AK, TLR-4 is important in early AK disease, and Th-17 genes are associated with adaptive immune responses to AK in animal models. Genetic screening of patients with AK to predict severity is viable and this would be expected to assist disease management.

The biology of Acanthamoeba keratitis

Acanthamoeba keratitis (AK) is a rare protozoal infection of the cornea. At least eight species of Acanthamoeba are known to cause this sight-threatening disease of the ocular surface. Acanthamoeba spp. exist in a wide array of niches ranging from thermal springs to under ice and every conceivable habitat in between. Contact lens wear is the leading risk factor for AK and is practiced by over 30 million individuals in the United States, yet the incidence of AK is less than 33 cases per one million contact lens wearers. Serological studies have reported that 90%-100% of individuals with no history of AK possess antibodies specific for Acanthamoeba antigens indicating that exposure to this organism is commonplace, yet disease is remarkably rare. Animal studies have shed light on the pathobiology and immunobiology of AK and indicate that a constellation of factors including the ocular surface microbiome and the microbiome of Acanthamoeba itself contribute to the pathogenesis of AK. Interesting, secretory antibodies produced by the adaptive immune response can prevent the initiation of corneal infection, but once Acanthamoeba trophozoites breach the corneal epithelium the adaptive immune system is helpless in altering the course of AK. It has been almost 50 years since AK was first described, yet many questions remain unanswered about this curious and enigmatic disease of the ocular surface.

How a Devastating Case of Acanthamoeba Sclerokeratitis Ended up with Serious Systemic Sequelae

A 35-year old soft contact lens wearer with a proven bilateral Acanthamoeba keratitis developed a nodular scleritis. Based on the stepladder approach described by Iovieno et al. [Ophthalmology. 2014 Dec;121(12):2340–7], nonsteroidal anti-inflammatory drugs, methylprednisolone, and later azathioprine were added to the antiamoebic treatment. Unfortunately, there was further deterioration and an endophthalmitis developed. Unbearable pain and concerns of spread to the brain urged an enucleation. Histopathological examination confirmed Acanthamoeba cysts in the cornea, sclera, retina, choroid, and vitreous body. As a side effect of the immunosuppressive treatment, the patient developed myopathy, pulmonary aspergillosis, and an avascular necrosis of the hip. Scleritis is a devastating complication of Acanthamoeba keratitis with a poor prognosis and a high enucleation rate. Acanthamoeba sclerokeratitis is, due to cyst-free biopsies, mostly assigned to an immune-mediated mechanism, justifying the use of immunosuppressive treatment. Scleritis in our case contributed to the extracorneal spread of Acanthamoeba. Our case is the first documented extracorneal spread of Acanthamoeba without previous surgery. Extracorneal spread of Acanthamoeba should be considered, even in the case of false-negative biopsies. We strongly recommend serial sections of the retrieved scleral specimen in case of negative histopathological examination to exclude an infection. Even when an immune-mediated scleritis is suspected, systemic immunosuppressive treatment should always be used with the greatest caution. Awareness of the side effects and monitoring by an experienced physician is mandatory.

Interstitial keratitis diagnosis and treatment

Interstitial keratitis is a non-ulcerative, non-suppurative, more or less vascularized inflammation of the corneal stroma. The corneal lesions result from the host response to bacterial, viral (40% of cases) or parasitic antigens, or from an autoimmune response (1% of cases) without active corneal infection. The natural history of the disease is divided into two phases: acute and cicatricial. This type of keratitis is less common than ulcerative bacterial keratitis, but it is a non-negligible cause of visual loss. It is associated with systemic or infectious disease and requires early diagnosis and appropriate treatment to optimize visual prognosis and avoid other complications.

Emerging Infections and Pertinent Infections Related to Travel for Patients with Primary Immunodeficiencies

In today's global economy and affordable vacation travel, it is increasingly important that visitors to another country and their physician be familiar with emerging infections, infections unique to a specific geographic region, and risks related to the process of travel. This is never more important than for patients with primary immunodeficiency disorders (PIDD). A recent review addressing common causes of fever in travelers provides important information for the general population Thwaites and Day (N Engl J Med 376:548-560, 2017). This review covers critical infectious and management concerns specifically related to travel for patients with PIDD. This review will discuss the context of the changing landscape of infections, highlight specific infections of concern, and profile distinct infection phenotypes in patients who are immune compromised. The organization of this review will address the environment driving emerging infections and several concerns unique to patients with PIDD. The first section addresses general considerations, the second section profiles specific infections organized according to mechanism of transmission, and the third section focuses on unique phenotypes and unique susceptibilities in patients with PIDDs. This review does not address most parasitic diseases. Reference tables provide easily accessible information on a broader range of infections than is described in the text.

Dacryoadenitis and extraocular muscle inflammation associated with contact lens-related Acanthamoeba keratitis: A case report and review of the literature

The present report discusses a new case of dacryoadenitis with extraocular muscle inflammation associated with Acanthamoeba keratitis (AK) in a contact lens wearer. A 41-year-old male, who has worn silicone hydrogel contact lenses on an extended basis for about 10 years, attended with the complaints of vision disturbance, hyperemia, and pain in his right eye. His history revealed that 1.5 month ago, he had been diagnosed with allergic conjunctivitis and had used steroid eye drops. Biomicroscopic examination revealed eyelid edema, chemosis, and ring infiltration, radial keratoneuritis and an epithelial defect in the cornea. Magnetic resonance imaging demonstrated enlarged lacrimal gland with edematous changes consistent with inflammation due to dacryoadenitis. There were also thickening and edema of the right superior oblique and lateral rectus muscle. The treatment protocol for AK was applied with no specific treatment for dacryoadenitis. After 4 months of the treatment, dacryoadenitis and keratitis regressed. Dacryoadenitis and extraocular muscle inflammation may accompany AK more frequently than expected and previously known. The evaluation of the lacrimal gland and extraocular muscles in presence of AK might be beneficial for understanding better the exact clinical picture and course of the keratitis.

[Diagnosis of Acanthamoeba keratitis]

The Acanthamoeba keratitis is a relatively rare, but dangerous disease of the cornea. Its development is thought to be associated with contact lens wearing as well as corneal microwounds contaminated with soil or water. The disease has no evident distinctive clinical features and is, therefore, difficult to be distinguished from herpetic or fungal keratitis. Nevertheless, Acanthamoeba infection can be suspected judging from anamnestic data (i.e. contact lens use and corneal injury with subsequent contamination of the wound), inadequately strong pain syndrome, ring-shaped infiltration of the cornea and ineffectiveness of conventional therapy. Also helpful may be such measures as isolating the bacteria using the method of biocultures, morphological examination of corneal biopsy material (using light and luminescent microscopy), genetic testing, and in vivo confocal microscopy of the cornea. Other promising methods are also listed in this article. A widely accepted diagnostic technique is yet, however, missing.

Use of multiple immunosuppressive agents in recalcitrant ACANTHAMOEBA scleritis

A 48-year-old woman who is a contact lens wearer presented with unilateral ACANTHAMOEBA keratitis, confirmed by PCR, which responded initially to topical polyhexamethylene biguanide (PHMB) and brolene. Three months later, despite continued treatment, she developed diffuse anterior scleritis with severe pain and marked scleral injection but without evidence of recurrence keratitis. Oral non-steroidal anti-inflammatories and oral high-dose corticosteroids were added without success. Subsequent treatment with intravenous methylprednisolone and high-dose cyclosporine led to a temporary improvement. Re-presenting with signs of recurrent scleritis and severe pain, the antitumor necrosis factor monoclonal antibody adalimumab, and later oral cyclophosphamide, were added. This led to complete quiescence of the scleritis. Unfortunately, frequent recurrences of ACANTHAMOEBA keratitis and anterior uveitis occurred on immunosuppression requiring continued treatment with PHMB, brolene and topical corticosteroids. This is the first case of severe refractory ACANTHAMOEBA scleritis requiring the concomitant use of four immunosuppressive agents to achieve continued disease control. The challenges in managing this case are discussed.

Granulomatous inflammation in Acanthamoeba sclerokeratitis

This report describes the histopathological findings in a patient with Acanthamoeba sclerokeratitis (ASK). A 58-year-old patient with ASK underwent enucleation and sections of the cornea and sclera were subjected to histopathology and immunohistochemistry with monoclonal mouse antihuman antibodies against T cell CD3 and B cell CD20 antigens. Hematoxylin and Eosin stained sections of the cornea revealed epithelial ulceration, Bowman's membrane destruction, stromal vascularization, infiltration with lymphocytes, plasma cells, and granulomatous inflammation with multinucleated giant cells (MNGC). The areas of scleritis showed complete disruption of sclera collagen, necrosis and infiltration with neutrophils, macrophages, lymphocytes, and granulomatous inflammation with MNGC. No cyst or trophozoites of Acanthamoeba were seen in the cornea or sclera. Immunophenotyping revealed that the population of lymphocytes was predominantly of T cells. Granulomatous inflammation in ASK is probably responsible for the continuance and progression of the scleritis and management protocols should include immunosuppressive agents alongside amoebicidal drugs.

Acanthamoeba sclerokeratitis

BACKGROUND

Acanthamoeba scleritis is an uncommon but severe complication of acanthamoeba keratitis. We report the clinical and histopathologic features of a patient with acanthamoeba sclerokeratitis.

METHODS

Review of the patient's clinical records and histopathologic examination of the globe including light microscopy and transmission electron microscopy.

RESULTS

Review of the clinical record of the patient revealed a past ocular history of penetrating keratoplasty for persistent acanthamoeba keratitis. Later in the course of treatment, the patient developed nodular necrotizing scleritis with culture-proven viable acanthamoeba in this area. She underwent enucleation of the eye for persistent acanthamoeba sclerokeratitis. Histopathologic examination of the globe revealed no acanthamoeba cysts or trophozoites at the site of crotherapy.

CONCLUSION

Our study provides evidence for the invasion of acanthamoeba organisms into the sclera in a case of acanthamoeba keratitis. The presence of trophozites in scleral tissue may exacerbate the immune response leading to nodular scleritis.

Visual Outcome and Rehabilitation in a Case of Bilateral Acanthamoeba Sclerokeratitis

PURPOSE

To report a rare and complicated case of bilateral Acanthamoeba sclerokeratitis (ASK).

METHODS

Case report of a 42-year-old patient who was referred to the Massachusetts Eye and Ear Infirmary 7 months after a history of culture-confirmed bilateral Acanthamoeba polyphaga sclerokeratitis. At the time of referral to the MEEI, he was noted to have iris neovascularization and chronic mydriasis in both eyes. The anterior chambers were shallow, and there were mature cortical cataracts that obscured the posterior pole in both eyes. His visual acuity in both eyes was limited to hand motions.

RESULTS

The patient underwent sequential cataract extraction, penetrating keratoplasty (PK), and yttrium-argon-garnet laser capsulotomy of the right eye over a span of 3 months. This treatment substantially improved the vision in his right eye to 20/400. Cataract extraction surgery and a PK have been scheduled for this patient's left eye in the near future.

CONCLUSIONS

Some patients with ASK and apparently poor visual prognosis can achieve substantial visual improvement after anterior-segment surgery. This report describes the management and outcome of only the second reported case of bilateral ASK in the world.

[Keratitis due to Acanthamoeba]

Free-living amebae appertaining to the genus Acanthamoeba, Naegleria and Balamuthia are the most prevalent protozoa found in the environment. These amebae have a cosmopolitan distribution in soil, air and water, providing multiple opportunities for contacts with humans and animals, although they only occasionally cause disease. Acanthamoeba spp. are the causative agent of granulomatous amebic encephalitis, a rare and often fatal disease of the central nervous system, and amebic keratitis, a painful disease of the eyes. Keratitis usually follows a chronic course due to the delay in diagnosis and subsequent treatment. The clear increase in Acanthamoeba keratitis in the last 20 years is related to the use and deficient maintenance of contact lenses, and to swimming while wearing them. The expected incidence is one case per 30,000 contact lens wearers per year, with 88% of cases occurring in persons wearing hydrogel lenses. This review presents information on the morphology, life-cycle and epidemiology of Acanthamoeba, as well as on diagnostic procedures (culture), appropriate antimicrobial therapy, and prevention measures.

Health effects of Acanthamoeba spp. and its potential for waterborne transmission

Risk from Acanthamoeba keratitis is complex, depending upon the virulence of the particular strain, exposure, trauma, or other stress to the eye, and host immune response. Bacterial endosymbionts may also play a factor in the pathogenicity of Acanthamoeba. Which factor(s) may be the most important is not clear. The ability of the host to produce IgA antibodies in tears may be a significant factor. The immune response of the host is a significant risk factor for GAE infection. If so, then a certain subpopulation with an inability to produce IgA in the tears may be at greatest risk. There was no sufficient data on the occurrence or types of Acanthamoeba in tapwater in the U.S. Published work on amoebal presence in tapwater does not provide information on the type of treatment the water received or the level of residual chlorine. Assessment of the pathogenicity by cell culture and molecular methods of Acanthamoeba in tapwater would also be useful in the risk assessment process for drinking water. The possibility that Acanthamoeba spp. might serve as vectors for bacterial infections from water sources also should be explored. The bacterial endosymbionts include an interesting array of pathogens such as Vibrio cholerae and Legionella pneumophila, both of which are well recognized waterborne/water-based pathogens. Work is needed to determine if control of Acanthamoeba spp. is needed to control water-based pathogens in water supplies.

Evaluation of hematoxylin and eosin and special stains for the detection of acanthamoeba keratitis in penetrating keratoplasties

PURPOSE

To compare the efficacy of a battery of routine and special histologic stains for the detection of acanthamoeba keratitis.

DESIGN

Observational study.

METHODS

Nine patients with culture-proven infectious keratitis whose clinical differential diagnosis included acanthamoeba and who had undergone penetrating keratoplasty were identified. Three cases each of culture-proven acanthamoeba, fungal, and herpes simplex keratitis were reviewed. Serial sections of the keratoplasty specimens were stained with hematoxylin and eosin, periodic acid-Schiff (PAS), Gomori methanamine silver (GMS), giemsa, Gram, calcofluor white, and acridine orange. Sections were reviewed in a random order and a masked fashion and classified as positive or negative for acanthamoeba, fungus, or herpes.

RESULTS

The correct diagnosis was made by examination of the hematoxylin and eosin stained slides in all cases. Correct diagnoses in decreasing order of frequency were made for slides stained with PAS, GMS, acridine orange, calcofluor white, giemsa, and Gram. There were false-positive diagnoses made only with calcofluor white and acridine orange stained slides because of staining of extracellular debris and other material.

CONCLUSIONS

When sections are examined by an experienced observer, hematoxylin and eosin is useful compared with calcofluor white, acridine orange, GMS, PAS, giemsa, and Gram stains for the detection of acanthamoeba keratitis.

Acanthamoeba sclerokeratitis: treatment with systemic immunosuppression

OBJECTIVE

This study describes the clinical features, management, and outcome of 19 patients who had severe Acanthamoeba sclerokeratitis (ASK) unresponsive to conventional management, requiring systemic immunosuppression to control disease.

DESIGN

Retrospective, non-comparative, interventional case series.

PARTICIPANTS

Records of all patients with Acanthamoeba keratitis treated at Moorfields Eye Hospital between 1989 and 2000 were reviewed. From more than 200 patients, 19 who developed ASK treated with systemic immunosuppression were identified.

MAIN OUTCOME MEASURES

Visual acuity, level of pain, and degree of inflammation were recorded after immunosuppressive treatment.

RESULTS

ASK requiring immunosuppression occurred in 20 eyes of 19 patients (11 males and 8 females). The mean age (mean +/- standard deviation) at onset was 38.6 +/- 13.2 years. On presentation, best-corrected visual acuity was counting fingers or worse in 11 eyes (55%), 6/18 to 6/60 in 5 eyes (25%), and 6/12 or better in 4 eyes (20%). The mean time between onset of initial symptoms of Acanthamoeba keratitis and commencement of systemic immunosuppression was 4.8 +/- 3.5 months. The mean duration of immunosuppression required to control inflammation was 7.2 +/- 3.9 months. Severe scleritic pain remained uncontrolled in two patients and resulted in enucleation. Best-corrected visual acuity at final follow-up was counting fingers or worse in eight eyes (40%), 6/18 to 6/60 in six eyes (30%), and 20/40 or better in six eyes (30%). The mean follow-up period after resolution of inflammation was 24.3 +/- 20.9 months (range, 0.2-59.7 months).

CONCLUSIONS

ASK is an uncommon complication of Acanthamoeba keratitis. The scleritis associated with this infection seems to be an immune-mediated response. After topical amebicidal treatment, systemic immunosuppression may be required to control the pain and tissue destruction associated with ASK.

Persistence of acanthamoeba antigen following acanthamoeba keratitis

AIM

To investigate the hypothesis that persistent corneal and scleral inflammation following acanthamoeba keratitis is not always caused by active amoebic infection but can be due to persisting acanthamoebic antigens

METHODS

24 lamellar corneal biopsy and penetrating keratoplasty specimens were obtained from 14 consecutive patients at various stages of their disease and divided for microscopy and culture. Histological sections were immunostained and screened for the presence of Acanthamoeba cysts by light microscopy. Cultures were carried out using partly homogenised tissues on non-nutrient agar seeded with E coli. Clinical data were obtained retrospectively from the case notes of these patients.

RESULTS

Of the 24 specimens, 20 were obtained from eyes that were clinically inflamed at the time of surgery. Acanthamoeba cysts were present in 16 (80%) of these 20 specimens, while only five (25%) were culture positive. Acanthamoeba cysts were found to persist for up to 31 months after antiamoebic treatment.

CONCLUSION

These findings support the hypothesis that Acanthamoeba cysts can remain in corneal tissue for an extended period of time following acanthamoeba keratitis and may cause persistent corneal and scleral inflammation in the absence of active amoebic infection. In view of these findings, prolonged intensive antiamoebic therapy may be inappropriate when the inflammation is due to retained antigen rather than to viable organisms

Management of infectious scleritis after pterygium excision

PURPOSE

We sought to describe the clinical features, responsible pathogens, management, and prognosis of infectious scleritis after pterygium excision.

METHODS

A retrospective study through review of medical records of patients diagnosed with infectious scleritis after pterygium excision over a 10-year period at our institution.

RESULTS

A total of 16 cases of infectious scleritis after pterygium excision was identified. Among them, eight were associated with sclerokeratitis, and six had multifocal scleral nodules with subconjunctival abscesses. Culture results were positive in 15 (93.8%) cases. Pseudomonas was isolated in 13 (81.3%) patients, fungus in three (18.8%), and two had a mixed growth (12.5%). Based on the in vitro susceptibility test, four (31%) Pseudomonas isolates were resistant to gentamicin, whereas all isolates were sensitive to amikacin. During the course of treatment, eight cases were complicated by vitreous opacity, four developed glaucoma, four had serous retinal or choroidal detachment, and two had secondary cataract. Scleral infection recurred in two patients after cessation of therapy. Among the nine patients treated with medical therapy, two eyes were enucleated, whereas only two attained a visual acuity of > or =2/200 at the end of the follow-up period. On the other hand, seven patients had combined antibiotic therapy and surgical debridement. The number of surgical debridement ranged from one to three, with an average of 1.4. In this combined-treatment group, only one patient required enucleation, and five cases attained a visual acuity of > or =2/200. The duration of hospitalization for patients with combined treatment was 21.2+/-4.8 days compared with the 28.4+/-5.0 days for those with medical treatment alone (p = 0.035).

CONCLUSION

Surgical debridement in combination with appropriate antimicrobial therapy shortens the course of treatment and improves the visual outcome of severe infectious scleritis after pterygium excision.

Results of a trial of combined propamidine isethionate and neomycin therapy for Acanthamoeba keratitis. Brolene Study Group

PURPOSE

To characterize patients with Acanthamoeba keratitis and to evaluate the safety and efficacy of propamidine isethionate 0.1% ophthalmic solution (Brolene) when administered concomitantly with neomycin-polymyxin B-gramicidin ophthalmic solution (Neotricin) in the treatment of Acanthamoeba keratitis.

DESIGN

Prospective, noncomparative case series.

METHODS

The authors report the clinical characteristics and outcomes of patients who entered this multicentered, open-label, clinical trial. Eighty-three patients with Acanthamoeba keratitis representing 87 infected eyes entered the trial.

RESULTS

Sixty (69%) of the 87 eyes enrolled had data analyzed for treatment efficacy and safety. Of these 60 eyes, 50 (83%) experienced treatment success. Thirty (60%) patients successfully treated adhered to treatment protocol guidelines. Patients who broke protocol had disease exacerbation during the maintenance therapy phase. The only eyes lost/enucleated were 7 of 17 in which penetrating keratoplasty was performed before eradication of the infectious agent.

CONCLUSION

Propamidine isethionate and neomycin are an effective treatment for Acanthamoeba keratitis. Penetrating keratoplasty should be performed only for visual rehabilitation and not to "debulk" an active infection. The authors advocate treating patients with topical medications, mainly Brolene, until all organisms are eradicated. There should be no signs of infection for at least 3 months in the patients not receiving antiamebic medications before penetrating keratoplasty is performed.

Acanthamoeba keratitis

Acanthamoeba species are an important cause of microbial keratitis that may cause severe ocular inflammation and visual loss. The first cases were recognized in 1973, but the disease remained very rare until the 1980s, when an increase in incidence mainly associated with contact lens wear was reported. There is an increased risk when contact lens rinsing and soaking solutions are prepared with nonsterile water and salt tablets. The clinical picture is often characterized by severe pain with an early superficial keratitis that is often treated as herpes simplex infection. Subsequently a characteristic radial perineural infiltration may be seen, and ring infiltration is common. Limbitis and scleritis are frequent. Laboratory diagnosis is primarily by culture of epithelial samples inoculated onto agar plates spread with bacteria. Direct microscopy of samples using stains for the cyst wall or immunostaining may also be employed. A variety of topically applied therapeutic agents are thought to be effective, including propamidine isethionate, clotrimazole, polyhexamethylene biguanide, and chlorhexidine. Various combinations of these and other agents have been employed, often resulting in medical cure, especially if treatment is commenced early in the course of the disease. Penetrating keratoplasty is preferably avoided in inflamed eyes, but may be necessary in severe cases to preserve the globe or, when the infection has resolved, to restore corneal clarity for optical reasons.

Surgically induced diffuse scleritis following cataract surgery

We report 21 cases, representing 3.1% of a total of 682 cataract patients, of surgically induced diffuse scleritis (SIDS) following planned extracapsular cataract extraction with intraocular lens insertion. The mean age was significantly lower in the patients with SIDS (mean 62.5 years; SD 13.68) when compared with the non-scleritic group (mean 73.6 years; SD 10.2; Mann-Whitney U-test, p = 0.0003). There was an association of SIDS with general anaesthetic (chi-squared test, p = 0.0008). Twenty of 21 patients responded to oral non-steroidal anti-inflammatory agents with good visual result.

Acanthamoeba sclerokeratitis

We treated a healthy soft contact lens wearer who developed Acanthamoeba sclerokeratitis in the left eye. The patient had severe pain and ring-shaped subepithelial infiltrates. The keratitis progressed and scleral nodules developed despite aggressive treatment with topical clotrimazole, dibromopropamidine isethionate, and corticosteroids. Corneal transplantation and cryotherapy were performed. The corneal button demonstrated Acanthamoeba cysts. Cultures of biopsy specimens taken from two different scleral nodules at two separate times were positive for Acanthamoeba. The disease progressed despite a second corneal graft and the addition of polyhexamethylene biguanide eyedrops. Enucleation of the left eye was required. Histopathologic examination of the specimen documented an Acanthamoeba cyst associated with a granulomatous inflammatory response deep in the sclera. Acanthamoeba scleritis may be associated with a poor prognosis, even with intensive medical and surgical treatment.

Infectious scleritis: report of four cases

While systemic autoimmune diseases are the main possibilities in the differential diagnosis of scleritis, other less common etiologies such as infections must also be considered. The authors report four cases of infectious scleritis to review predisposing factors, clinical characteristics, methods of diagnostic approach, and response to therapy. Two patients had primary scleritis and two patients had secondary scleritis following extension of primary corneal infection (corneoscleritis). Diagnoses included three local infections (one each with Staphylococcus. Acanthamoeba, and herpes simplex) and one systemic infection (Lyme disease). Stains, cultures, or immunologic studies from scleral, conjunctival, and/or corneal tissues, and serologic tests were used to make the diagnosis. Medical therapy, including antimicrobial agents, was instituted in all patients, and surgical procedures were additionally required in two patients (scleral grafting in one and two penetrating keratoplasties in another); the patient who required two penetrating keratoplasties had corneoscleritis and underwent eventual enucleation. Infectious agents should be considered in the differential diagnosis of scleritis.

Prognosis for keratoplasty in Acanthamoeba keratitis

STUDY

Penetrating keratoplasty (PK) was undertaken between 1985-1991 at Moorfields Eye Hospital in 13 eyes (19 PKs) of 11 patients who developed Acanthamoeba keratitis. Infection was ultimately controlled in all cases. Retrospective analysis was undertaken to establish risk factors for PK. Six eyes were quiet and 7 had uncontrolled infection at the time of keratoplasty. The outcome for these was compared.

COMPLICATIONS

Complications included cataract in 50% of quiet eyes and 100% of inflamed eyes. Intumescent cataract resulted in glaucoma requiring drainage surgery in 4 eyes. Graft rejection episodes occurred in 50% of quiet eyes, but were treated aggressively and did not cause graft failure.

RESULTS

Graft survival was excellent for quiet eyes, but was compromised by recurrent infection in inflamed eyes and 6 patients were regrafted. Survival compared poorly with grafting for active herpetic or bacterial keratitis, indicating that early diagnosis and treatment are essential for adequate control of this disease.

Six cases of scleritis associated with systemic infection

Isolated scleritis (without keratitis) associated with infections is uncommon, and correct diagnosis and appropriate therapy for it are often delayed. Six patients with infection-associated scleritis were seen at our institution between May 1983 and May 1990 (these patients represented 4.6% of all patients with scleritis [six of 130 patients] in that period). Three of these cases were associated with systemic infections. One was associated with syphilis, one was associated with tuberculosis, and one was associated with toxocariasis. Three cases resulted from local infections. One was associated with infection with Proteus mirabilis, one was associated with infection with herpes zoster virus, and one was associated with infection with Aspergillus. The Aspergillus infection developed after trauma and the P. mirabilis-induced infection developed after strabismus surgical procedures. Four of the six cases were initially misdiagnosed and inappropriately managed. Correct diagnosis was made seven days to four years after onset of symptoms. Review of systems, scleral biopsy, culture, and laboratory investigation were used to make the diagnosis. Differential diagnosis of scleritis must include infective agents.

Exudative retinal detachment and posterior scleritis associated with massive scleral thickening and calcification treated by scleral decompression

A 66-year-old man presented with massive bilateral scleral thickening and calcification associated with a unilateral exudative retinal detachment which did not respond to systemic anti-inflammatory agents including steroids and cyclophosphamide but improved with scleral resection. This patient shows the features of both posterior scleritis and the uveal effusion syndrome, providing further evidence for the role of a thickened sclera and interference with the trans-scleral flow of fluid in the formation of such an exudative retinal detachment.

Use of corticosteroids in combination with antimicrobial drugs in the treatment of infectious corneal disease

The use of corticosteroids in the management of infectious eye disease is controversial. In this study, the authors attempt to analyze the goals and risks of the use of corticosteroids in the treatment of various forms of infectious keratitis with reference to generally recognized principles for the treatment of infectious diseases. Existing clinical and research data are reviewed in this context to make appropriate recommendations for the use of corticosteroids in the treatment of bacterial, fungal, and acanthamoeba keratitis. The authors conclude that corticosteroids are definitely contraindicated in the treatment of fungal keratitis, and relatively contraindicated in the treatment of Acanthamoeba keratitis. Topical corticosteroid therapy may have a role in the treatment of bacterial keratitis if appropriate guidelines are followed.

Successful medical management of Acanthamoeba keratitis

Seven patients with documented Acanthamoeba keratitis were treated with prolonged and intensive triple antiamoebic therapy consisting of topical neomycin-polymyxin B-gramicidin, propamidine isethionate 0.1%, and miconazole nitrate 1%. Additionally, five patients were treated with topical corticosteroids. Six of seven patients were cured of Acanthamoeba keratitis with medical therapy alone, one patient required therapeutic penetrating keratoplasty to eradicate the infection. Two patients underwent penetrating keratoplasty to improve their vision after medical therapy. Our series differs from previous reports in that triple antiamoebic therapy was used in all seven patients and was successful in both early and advanced cases of Acanthamoeba keratitis. Prolonged and intensive topical therapy with these three antiamoebic drugs may be an effective mode of therapy for Acanthamoeba keratitis.

The epidemiology of Acanthamoeba keratitis in the United States

We surveyed members of the Ocular Microbiology and Immunology Group and reviewed laboratory requests at the Centers for Disease Control to determine better the epidemiology of Acanthamoeba keratitis in the United States. A total of 208 cases of Acanthamoeba keratitis were identified. The number of cases increased gradually between 1981 and 1984, with a dramatic increase beginning in 1985. Males and females were equally affected. Of the 208 patients, 85 (41%) resided in California, Texas, Florida, or Pennsylvania. Of 189 patients, 160 (85%) wore contact lenses, predominantly daily-wear or extended-wear soft lenses. Of the 138 patients who wore contact lenses and for whom information was available, 88 (64%) used saline prepared by dissolving salt tablets in distilled water. Patients aged 50 years and older were more likely to have had a history of trauma than younger patients, and males were more likely to have a history of trauma than females.

Chorioretinitis in the contralateral eye of a patient with Acanthamoeba keratitis

Chorioretinitis developed in the right eye of a patient with contact lens-associated Acanthamoeba keratitis in the left eye during an acute exacerbation of the keratitis. This chorioretinitis may have resulted from hematogenous dissemination from his corneal infection.

Treating Cushing's disease

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Acanthamoeba keratitis

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