Postmarketing Surveillance of Corneal Edema, Fuchs Dystrophy, and Amantadine Use in the Veterans Health Administration

Amantadine-induced corneal edema: A case and literature review

Purpose

To present a case of irreversible corneal edema after 10 years of amantadine use. A literature review was carried out to describe the clinical characteristics and outcomes of amantadine-induced corneal edema.

Observations

A 36-year-old woman presented with a 6-week history of gradually progressive bilateral painless visual loss with visual acuity (VA) of 20/350 and 20/300 in the right and left eye, respectively. Examination showed bilateral diffuse central corneal edema with multiple Descemet membrane folds without endothelial guttata, keratic precipitates or intraocular inflammation. This did not respond to hypertonic saline drops and empirical treatment for presumed herpetic endotheliitis with oral acyclovir. Medication review revealed the use of amantadine 100mg daily for the past 10 years, prescribed by her neurologist for fatigue. Despite discontinuing amantadine, corneal edema was irreversible due to a markedly reduced endothelial cell count of 625 (right) and 680 cells/mm2 (left).

Conclusions and Importance

This case highlights the need to consider amantadine as a cause of unexplained bilateral non-guttae corneal edema. A literature review of 33 case reports revealed broadly similar features of amantadine-induced corneal edema; whilst most cases had favorable outcomes with median VA 20/25 (interquartile range IQR 20/20-20/30) and complete resolution of corneal edema within 30 days (IQR 14-35) of amantadine discontinuation, most experienced low endothelial cell density 759 cells/mm2 (IQR 621-1078). Taken together, screening specular microscopy ought to be considered for those in whom amantadine is likely required long-term.

Amantadine induced interface fluid formation after LASIK. A case report

Purpose

To describe a case of bilateral interface fluid formation 2 years after laser-assisted in situ keratomileusis (LASIK) surgery caused by the side effect of amantadine.

Observations

A 47-year-old male patient with a history of Parkinson's disease treated with amantadine who had uneventful LASIK surgery in both eyes 2 years ago, presented with a decline in vision over the past 6 weeks. Results: Best corrected vision was 20/200 and 20/400 in the right and left eye respectively. Intraocular pressures were measured within the normal range. Biomicroscopic exam showed bilateral corneal edema. Anterior segment optical coherence tomography (AS-OCT) revealed fluid accumulation within the LASIK flap interface in both corneas. The patient's corneal edema and fluid in the interface began to gradually resolve, and vision improved 2 weeks after discontinuing amantadine.

Conclusions and Importance

Although there is no previous report, it is possible that amantadine may cause interface fluid formation in patients with LASIK surgery.

Ocular Surface Features in Patients with Parkinson Disease on and off Treatment: A Narrative Review

Parkinson disease (PD) is a progressive, neurodegenerative disease of the central nervous system. Visual disturbance is one of the most frequent nonmotor abnormalities referred to by patients suffering from PD at early stages. Furthermore, ocular surface alterations including mainly dry eye and blink reduction represent another common finding in patients with PD. Tears of PD patients show specific alterations related to protein composition, and in vivo confocal microscopy has demonstrated profound changes in different corneal layers in this setting. These changes can be attributed not only to the disease itself, but also to the medications used for its management. In particular, signs of corneal toxicity, both at epithelial and endothelial level, are well described in the literature in PD patients receiving amantadine. Management of PD patients from the ophthalmologist's side requires knowledge of the common, but often underdiagnosed, ocular surface alterations as well as of the signs of drug toxicity. Furthermore, ocular surface biomarkers can be useful for the early diagnosis of PD as well as for monitoring the degree of neural degeneration over time.

Amantadine-induced bilateral corneal edema in a pediatric patient

Amantadine was originally developed as an antiviral agent for influenza A. However, it also has off-label uses for Parkinson disease, multiple sclerosis, and in the management of extrapyramidal symptoms. The mechanism of action in these conditions has yet to be elucidated. Ocular side effects from systemic amantadine are rare but have been described in three previous reports of amantadine-associated corneal edema in the pediatric population. We present an additional case of amantadine-associated transient visual impairment in a patient, which was associated with significant regression and worsening of his underlying neurodevelopmental status.

Corneal Edema Associated With Systemic Dopaminergic Agents

PURPOSE

To describe the development and resolution of corneal edema in 3 patients who were exposed to compounds that stimulate dopaminergic pathways.

METHODS

We conducted a review of the literature on bilateral corneal edema secondary to amantadine use and report a case series of corneal edema seen in an outpatient ophthalmology specialty clinic, shortly after exposure to agents that enhance dopamine transmission.

RESULTS

Cases 1 and 2 report a 25-year-old man with attention-deficit hyperactivity disorder and a 73-year-old man with Parkinson disease who were placed on dopaminergic medications to treat their conditions. The former was administered methylphenidate and the latter patient was administered ropinirole. Both patients developed corneal edema soon afterward. Case 3 is a 67-year-old man with a recent exposure to resin from Euphorbia resinifera, a cactus in his garden. After cessation of the offending medications and treatment for exposure to resiniferatoxin, the corneal edema progressively resolved and visual acuity returned to baseline in all 3 cases.

CONCLUSIONS

Methylphenidate, ropinirole, and resiniferatoxin have different mechanisms of actions but have a common end point leading to increased dopamine. We believe that these agents are linked with the reversible corneal edema seen in our 3 patients. This strongly correlates with previous studies that have linked amantadine, a drug that blocks dopamine reuptake, to reversible corneal edema.

Clinical and genetic investigation of amantadine-associated corneal edema

PURPOSE

Amantadine use has been temporally associated with bilateral corneal edema in a series of cases; however, its pathophysiological mechanisms have yet to be elucidated. We sought to rule out subclinical Fuchs dystrophy as a contributor, characterize its pattern of corneal edema, and describe the long-term outcome of concurrent topical steroids while resuming amantadine.

PATIENT AND METHODS

After a 44-year-old woman presented with new acute onset bilateral corneal edema, amantadine was discontinued, with clinical improvement. However, neurological decompensation required restarting amantadine, which she did concurrently with topical loteprednol. To determine whether subclinical Fuchs dystrophy might be present, triplet-primed polymerase chain reaction was conducted to measure copy number of the CTG18.1 trinucleotide repeat in TCF4. Specular microscopy and Scheimpflug imaging were conducted and followed for 32 months to assess for resolution and stability. Literature review was conducted to assess for consistency of the clinical phenotype.

RESULTS

Corneal edema resolved clinically 4 weeks after discontinuation of amantadine. Serial Scheimpflug imaging demonstrated resolution of posterior and central corneal edema and specular microscopy revealed intracellular opacities with loss of endothelial cell density. Despite resuming amantadine, Scheimpflug imaging and specular microscopy measurements remained stable at 32 months. Triplet-primed PCR of CTG18.1 in TCF4 revealed no trinucleotide repeat expansion.

CONCLUSIONS

Amantadine-associated corneal edema is characteristically posterior and central and appears unlikely to represent early or subclinical decompensation of Fuchs dystrophy. We describe the unique outcome of continued corneal clearance after restarting amantadine concurrently with steroids, a pattern that has persisted over 32 months to date.

Amantadine-Induced Corneal Edema in a Pediatric Neuro-Oncology Patient: A Case Report

Amantadine is commonly prescribed as a neurostimulant in patients with brain injuries. This is a case of a 14-year-old male with a history of brain tumor that developed corneal edema after initiation of amantadine, a rare but documented side effect of this medication. After discontinuation of amantadine, the corneal edema resolved within two months, but endothelial cells density remained low. LEVEL OF EVIDENCE: V.

Acute corneal edema without epithelium compromise. A case report and literature review

El edema de córnea es una entidad que se produce por un gran número de causas y tiene diversas formas de presentación y diferentes grados de afección. En este artículo se reporta el caso de un hombre con edema de córnea agudo sin compromiso epitelial, en el que el cuadro clínico, el examen oftalmológico y los estudios de extensión no lograron establecer su etiología. Además, se hace una revisión de la literatura disponible respecto a todas las posibles causas de edema de córnea agudo, agrupándolas en aquellas que ocasionan el edema por lesión o inflamación epitelial o estromal, por disfunción endotelial o por un aumento en la presión intraocular.

Amantadine Use as a Risk Factor for Corneal Edema: A Nationwide Cohort Study in Taiwan

PURPOSE

To evaluate the association between amantadine use and corneal toxicity in a nationwide population.

DESIGN

Retrospective cohort study of nationwide population-based administrative database.

METHODS

This study analyzed data in the Taiwan Longitudinal Insurance Database for a group of 8195 patients diagnosed with Parkinson disease during a 15-year period (January 1, 1996 to December 31, 2010). A control group of 8195 patients without Parkinson disease was randomly matched with the Parkinson group by age, sex, and comorbidity index. The Kaplan-Meier method was used to calculate the cumulative incidence of corneal edema. Incident rate ratios and Cox proportional hazard regressions were estimated to compare the risk of corneal edema. The same methods were then used to compare the risk between patients with and without amantadine treatment.

RESULTS

The incidence of corneal edema in the Parkinson group (123 patients; 1.50%) was significantly higher than that in the control group (82 patients; 1.0%) (P = .004). The incidence ratio for corneal edema in the Parkinson group vs the controls was 5.77. When the Parkinson group was further subgrouped by use and non-use of amantadine, the hazard ratio for corneal edema was 1.79 times higher in the amantadine subgroup. Analyses of the amantadine subgroup by cumulative dose revealed that the 30-day hazard ratio for corneal edema was 2.05 higher in patients given moderate doses (2000-4000 mg) of amantadine and 2.84 times higher in the subgroup of patients given high doses (>4000 mg).

CONCLUSIONS

Amantadine increases the risk of corneal edema in a dose-dependent manner.

The effect of systemic amantadine sulfate on malondialdehyde and total thiol levels in rat corneas

Purpose:

To evaluate the malondialdehyde (MDA) and total thiol (sulfhydryl, SH) levels in rat corneas after intraperitoneal injection of amantadine sulfate.

Methods:

A total of 12 Wistar albino rats were divided into two groups: control group (n = 6) and amantadine group (n = 6). Balanced salt solution (1 mL, 0.9% NaCl, twice/day) was injected into rats in control group. Amantadine sulfate (2 mg/1 mL, twice/day) was injected into rats in amantadine group. In each group, two rats were injected for 1 week, two received injections for 1 month, and two rats received injections for 3 months. The corneas were homogenized and MDA and SH levels were measured spectroflourometrically.

Results:

In control group, median MDA and SH levels were 2.37 (range, 0.92-3.60) and 25.35 (range, 6.30-54.0) nmol/mg, respectively. In amantadine group, median MDA and SH levels were 3.57 (range, 1.25-5.92) and 32.65 (range, 3.30-48.3) nmol/mg, respectively. The difference between this two groups regarding MDA (P = 0.14) and SH (P = 1.0) levels was statistically insignificant.

Conclusion:

Systemically administered amantadine sulfate seems not to cause MDA and SH imbalance in rat corneas.

Safety overview of FDA-approved medications for the treatment of the motor symptoms of Parkinson's disease

INTRODUCTION

Parkinson's disease (PD) is among the most common of the neurodegenerative disorders. Treatment is primarily focused on correcting neurotransmitter imbalances. Several classes of medication are available for this purpose.

AREAS COVERED

A Medline search was performed to gather information about the safety of the medications approved for the treatment of the motor symptoms of PD. This was supplemented with additional articles obtained from online sources and information provided by the FDA and the manufacturers. The focus of this review is the side-effect and safety profiles of carbidopa/levodopa, dopamine agonists, selective monoamine oxidase inhibitors, catechol-o-methyltransferase inhibitors, anticholinergics and amantadine.

EXPERT OPINION

Though serious side-effects may occur, as a group, the medications used for the treatment of PD motor symptoms tend to produce side-effects that are mild to moderate in nature, and that primarily reflect the focus on dopaminergic therapies. Care plans for Parkinson's patients should be approached based on the needs of the individual as disease presentation, lifestyle, level of disability, concurrent disease states and the presence of non-motor symptoms make each case unique. Patients and caregivers must have realistic expectations about the use of PD medications.

Amantadine induced reversible corneal edema

Amantadine is becoming more commonly used for Parkinson's disease (PD), particularly for its efficacy in treating the drug-induced dyskinesias. Corneal edema is a known but unusual side effect of amantadine therapy, rarely reported in the neurological literature. We report amantadine-induced reversible corneal edema in a patient with advanced PD.

Bioengineering endothelialized neo-corneas using donor-derived corneal endothelial cells and decellularized corneal stroma

Corneal transplantation is a common transplant procedure performed to improve visual acuity by replacing the opaque or distorted host tissue by clear healthy donor tissue. However, its clinical utility is limited due to a lack of high quality donor corneas. Bioengineered neo-corneas, created using an expandable population of human donor-derived corneal endothelial cells (HCEC), could address this current shortage. The objectives of this study were to establish HCEC isolation and culture protocols and to investigate the feasibility of bioengineering corneal tissue constructs by seeding the cells on decellularized human corneal stroma. HCECs were removed from the discarded corneas of eye donors by enzymatic digestion. Cells were expanded and evaluated for their expression of Na(+)/K(+)-ATPase and zona occludens-1 (ZO-1). Donor corneal stromas were cut to 120-200 microm thickness slices using a microtome and then decellularized. Extracellular matrix components and mechanical properties of the scaffolds were measured after decellularization. To engineer neo-corneas, 130 HCEC/mm(2) were seeded on decellularized human corneal stromas. The resulting constructs were placed in growth medium for 14 days and then analyzed using scanning electron microscopy (SEM), histology, and immunocytochemistry. Seeded cells retain expression of the functional markers Na(+)/K(+)-ATPase and ZO-1 and constructs have biomechanical properties similar to those of normal corneas. These results indicate that construction of neo-corneas, using HCECs derived from discarded donor corneas and decellularized thin-layer corneal stromas, may create a new source of high quality corneal tissue for transplantation.

Corneal endothelial dysfunction associated with amantadine toxicity

PURPOSE

To describe bilateral corneal endothelial dysfunction in a patient with Parkinson disease who was treated with long-term amantadine.

METHODS

We employed an A-B-A-B single-subject research design that included clinical history, clinical findings, photographic images, and specular microscopic findings of ocular changes.

RESULTS

A 52-year-old woman with Parkinson disease who had taken amantadine for 6 years had bilateral corneal edema for 2 months at baseline. After cessation of amantadine, the edema resolved, and the endothelial cell densities were <or=600/mm. Corneal edema recurred when the administration of amantadine was resumed. Therefore, amantadine was permanently discontinued and the cornea cleared again.

CONCLUSIONS

Amantadine can cause reversible corneal edema but can irreversibly reduce the density of endothelial cells.

Amantadine-associated corneal edema potentially irreversible even after cessation of the medication

PURPOSE

To describe the clinical features of 3 patients with amantadine-associated corneal edema, including the histopathologic findings from 1 patient who underwent corneal transplantation for irreversible corneal edema.

DESIGN

Interventional case series.

PARTICIPANTS

Three patients who sought treatment at the authors' institution with abrupt-onset, bilateral, diffuse corneal edema associated with systemic amantadine use.

METHODS

Retrospective chart review.

MAIN OUTCOME MEASURES

Visual acuity, corneal thickness, slit-lamp observations, and histopathologic findings.

RESULTS

The duration of use of amantadine ranged from 2 months to 6 years before onset of corneal edema. Discontinuation of amantadine resulted in resolution of corneal edema in both eyes of 2 patients. A third patient underwent a full-thickness corneal transplantation, and subsequently, edema developed in the grafted cornea. Cessation of amantadine therapy in this patient resulted in resolution of corneal edema in both eyes, but the ungrafted corneal eventually decompensated and became edematous, requiring corneal transplantation. Histopathologic analysis of the cornea buttons showed significant loss of endothelial cells.

CONCLUSIONS

Amantadine can cause corneal edema that begins a few months to several years after institution of therapy, and the edema can occur even in a corneal graft. Prolonged corneal edema in the setting of amantadine use can be irreversible. In cases of corneal edema without an obvious causative disease, the systemic medication list of the patient must be reviewed, and amantadine must be considered as a possible cause.