Amiodarone induced optic neuropathy

Amiodarone-related keratopathy and optic neuropathy: case report and literature review

Amiodarone, a highly effective yet lipophilic antiarrhythmic drug with prolonged half-life, is associated with systemic and ocular complications. While keratopathy being the most prevalent, affecting 70-100% of long-term users, amiodarone-associated optic neuropathy (AAON), though rare (incidence: 0.36-2%), can induce diverse visual impairments, ranging from mild deficits to profound vision loss. Given that patients on amiodarone frequently possess the risk factors of vascular diseases, it is essential to differentiate the diagnosis of AAON from non-arteritic anterior ischemic optic neuropathy (AION). This study reports a 61-year-old man who developed both corneal deposition and optic neuropathy during systemic amiodarone therapy. We further analyze the clinical features of keratopathy and optic neuropathy caused by amiodarone through a comprehensive literature review, aiming to enhance diagnostic recognition and management strategies.

Amiodarone-Associated Optic Neuropathy in a Patient With Associated Arrhythmia

Amiodarone is a commonly used antiarrhythmic used to treat atrial fibrillation and ventricular tachycardias. While this agent can present with pulmonary, thyroid, and hepatic side effects, it can also, less commonly cause neurologic toxicity, particularly optic neuropathy. Optic neuropathy can manifest as acute vision loss. The management of amiodarone-associated optic neuropathy (AAON) includes early recognition of symptom manifestation so that the medication can be discontinued promptly. Here, we describe a case of a 64-year-old male who developed acute onset complete left-sided vision loss after initiation of amiodarone.

Clinical and Mechanistic Review of Amiodarone-Associated Optic Neuropathy

Amiodarone-associated optic neuropathy (AAON) is a complex clinical diagnosis, requiring distinction from non-arteritic ischemic optic neuropathy (NAION) due to a shared at-risk patient population. Diagnosis of AAON is complicated by a varied clinical presentation and incomplete pathophysiologic mechanisms. This article reviews pertinent literature for describing and clinically delineating AAON from NAION, as well as newly reported protective mechanisms of insulin-like growth factor 1 (IGF-1) and PI3K/Akt against amiodarone-induced oxidative and apoptotic injury in retinal ganglion and pigment epithelial cells. These studies offer a basis for exploring mechanisms of amiodarone toxicity in the optic nerve.

The ocular adverse effects of oral drugs

Some commonly prescribed drugs have ocular adverse effects. Many parts of the eye can be affected by oral drugs. Some ocular adverse effects may be reversed with medical or surgical intervention whereas other drugs may cause irreversible loss of vision

The risk of visual loss can be reduced by a number of approaches, including monitoring for ocular toxicity, reducing the drug dose, or stopping the drug and looking for an alternative. This can be supported by good communication between the prescribing clinician and ophthalmologist

Infrequent or delayed ocular adverse effects may not be identified in clinical trials of new drugs. Reporting adverse events is therefore important

[Drug-induced toxic optic neuropathy]

Drug-induced optic neuropathy is a group of disorders in which medications cause degeneration of the optic nerve. The true prevalence of drug-induced neuropathy has not been studied, although the percentage of patients who develop optic nerve damage is known for individual medications. The common pathophysiological mechanisms are believed to be mitochondrial damage and imbalance of intracellular and extracellular free radical homeostasis. Typical symptoms of drug-induced neuropathy are reduced visual acuity in the central area, which is often bilateral, visual field disturbances, dyschromatopsia, and edema of the optic nerve head. Early detection of drug-induced optic neuropathy can potentially prevent or minimize serious complications. For patients who develop drug-induced optic neuropathy, treatment is based on timely diagnosis and cancellation of the provoking drug. In most patients, vision usually recovers a few weeks or months after discontinuation of previous therapy, but there have been cases of irreversible vision loss. In addition to withdrawal of the drug that caused optic nerve lesion, treatment of drug-induced neuropathy may include use of drugs and treatment methods prescribed by neurologists for peripheral neuropathy, however, such treatment is seldom based on evidence.

[Amiodarone-induced optic neuropathy: A rare side effect]

INTRODUCTION

The diagnosis of bilateral papilledema implies emergency medical care to look for intracranial hypertension and arteritic ischemic neuropathy. However, other causes must also be mentioned, including drugs. Too often underrated because of their usual benignity, drug side ophthalmological effects can be severe and are typically bilateral.

CASE REPORT

An 80-year-old woman was hospitalized for bilateral papilledema, predominantly in the left eye, with lowered visual acuity. After ruling out intracranial hypertension, arteritic ischemic optic neuropathy, non-arteritic, and inflammatory bilateral papilledema, the diagnosis was toxic optic neuropathy.

CONCLUSION

Bilateral edematous optic neuropathy is a known side effect of amiodarone, uncommon but to be known because of the large number of patients benefiting from this treatment.

[Clinical aspects of treatment with amiodarone]

Amiodarone has multiple and complex electrophysiological effects that render it a very effective antiarrhythmic drug for the treatment of both, supraventricular and ventricular arrhythmias. Proarrhythmic effects of amiodarone in patients with structural heart disease are rare. However, extracardiac adverse effects occurring in association with amiodarone treatment are frequent and feared. These adverse effects have usually been related to total amiodarone exposure (i. e., dose and duration of treatment). Parallel to a more frequent use of lower amiodarone maintenance doses (100-200 mg/day), the incidence of severe unwanted extracardiac side effects has decreased. High-dose maintenance regiments (daily dose ≥300 mg) are usually obsolete. This paper discusses recommendations regarding the monitoring of cardiac and extracardiac side effects of amiodarone. They need to be regarded by physicians using amiodarone to ensure long-term safety of amiodarone therapy.

Amiodarone-associated Optic Neuropathy-A Clinical Criteria-based Diagnosis?

Amiodarone-associated optic neuropathy (AAON) is a controversial diagnosis with possible impact on vital cardiac therapy decisions. This retrospective case series aims for application of distinguishing features of AAON versus non-arteritic ischaemic optic neuropathy (NAION): Bilaterality, mode of onset, degree of optic nerve dysfunction, structure of uninvolved disc (unilateral cases), and systemic toxic effects. Applying these criteria to patients with disc swelling under amiodarone, the authors identified four unilateral disc swellings, one with NAION-typical features only and three with one or more NAION-atypical features. All three sequential and six bilateral cases showed one or more NAION-atypical features. The 12 cases highlight the persisting diagnostic dilemma arising from diversity of presentation, lack of plausible pathomechanism, and controversial existence of the entity itself.

Stem Cell Ophthalmology Treatment Study: bone marrow derived stem cells in the treatment of non-arteritic ischemic optic neuropathy (NAION)

Background

Ten patients with bilateral visual loss due to sequential non-arteritic ischemic optic neuropathy (NAION) underwent autologous Bone Marrow Derived Stem Cell (BMSC) therapy within the Stem Cell Ophthalmology Treatment Study (SCOTS). SCOTS is an Institutional Review Board approved clinical study utilizing autologous BMSC in the treatment of optic nerve and retinal diseases that meet inclusion criteria.

Methods

The average age of the patients treated was 69.8 years. The average duration of visual loss in eyes treated was 9.8 years and ranged from 1 to 35 years. Affected eyes were treated with either retrobulbar, subtenons and intravenous BMSC or, following vitrectomy, intra-optic nerve, subtenons and intravenous BMSC. The primary outcome was visual acuity as measured by Snellen or converted to LogMAR.

Results

Following therapy in SCOTS, 80% of patients experienced improvement in Snellen binocular vision (P=0.029) with 20% remaining stable; 73.6% of eyes treated gained vision (P=0.019) and 15.9% remained stable in the post-operative period. There was an average of 3.53 Snellen lines of vision improvement per eye with an average 22.74% and maximum 83.3% improvement in LogMAR acuity per eye. The average LogMAR change in treated eyes was a gain of 0.364 (P=0.0089). Improvements typically manifested no later than 6 months post procedure.

Conclusions

The use of BMSC in the Stem Cell Ophthalmology Treatment Study achieved meaningful visual improvements in a significant percentage of the NAION patients reported. Improvements typically manifested no later than 6 months post-procedure. Duration of visual loss did not appear to affect the ability of the eyes to respond to treatment. Possible mechanisms by which visual improvement occurred may include BMSC paracrine secretion of proteins and hormones, transfer of mitochondria, release of messenger RNA or other compounds via exosomes or microvesicles and neuronal transdifferentiation of the stem cells.

Amiodarone-Associated Optic Neuropathy: Clinical Review

Amiodarone, an antiarrhythmic agent, has been associated with visual loss secondary to optic neuropathy. The reported mean duration of amiodarone use before visual loss is about 9 months. Patients receiving amiodarone have a 2-fold increased risk of developing optic neuropathy, especially in males and possibly in patients with longer duration of treatment. Amiodarone-associated optic neuropathy is characterised by an insidious onset, slow progression, bilateral simultaneous visual loss, and protracted disc swelling. After discontinuing amiodarone use, visual acuity and visual field deficits tend to improve or stabilise in most patients, with about 20% of the patients getting worse.

Behaviour of disc oedema during and after amiodarone optic neuropathy: case report

A 73-year-old woman with atrial fibrillation treated with Amiodarone presented with Optic Disc oedema in right eye (OD). Using Optical Coherence Tomography (OCT) we describe the impact of this neuropathy on Retinal Nerve Fibre Layer (RNFL). At diagnosis RNFL average was of 188 μm OD and 77 μm in the left eye (OS), six months after discontinuation of the drug decreased to 40 μm in OD and 76 μm in OS. The RNFL average of OD presented a transient increase during the acute oedema that returned to normal levels during the first month after discontinuation of the drug and fell dramatically to 44 μm at the second month and 40 μm at the sixth month. We show there is axonal loss after amiodarone-associated optic neuropathy measured with OCT. The OCT may be used in these patients to document changes in RNFL in the follow-up.

Two cases of bilateral amiodarone-associated optic neuropathy

INTRODUCTION

The widespread use of amiodarone is limited by its toxicity, notably to the optic nerve. We report two cases of bilateral optic nerve neuropathy due to amiodarone, and provide a detailed description of the disease.

OBSERVATIONS

The first case was a 59-year-old man complaining from insidious monocular loss of vision within ten months of initiating amiodarone. Funduscopy and optical coherence tomography showed bilateral optic disc edema. The second case was a 72-year-old man presenting with a decrease in visual acuity in his left eye for a month. Funduscopy showed a left optic nerve edema, and fluorescein angiography showed bilateral papillitis. In both cases, the clinical presentation was not suggestive of ischemic neuropathy, because of the preservation of visual acuity and the insidious onset. In addition, both cardiovascular and inflammatory work-up were normal. An amiodarone-associated neuropathy was suspected, and amiodarone was discontinued with the approval of the cardiologist, with complete regression of the papilledema and a stabilization of visual symptoms.

DISCUSSION

Differentiating between amiodarone-associated optic neuropathy and anterior ischemic optic neuropathy may be complicated by the cardiovascular background of such patients. The major criterion is the absence of a severe decrease in visual acuity; other criteria are the normality of cardiovascular and inflammatory work-up, and the improvement or the absence of worsening of symptoms after discontinuation of amiodarone.

CONCLUSION

Amiodarone-associated neuropathy remains a diagnosis of exclusion, and requires amiodarone discontinuation, which can only be done with the approval of a cardiologist, and sometimes requires replacement therapy.

Toxic optic neuropathies

PURPOSE OF REVIEW

Many causes of toxic optic neuropathy have been described to date and novel causes of toxicity are continuously being added to the current literature. The pathophysiological basis for the toxicity or a direct causal relationship is yet to be determined for many of these agents. This review highlights the reports made over the last year about the commonly reported agents, with emphasis on the mechanisms of toxicity.

RECENT FINDINGS

Mitochondria of retinal ganglion cells and papillomacular bundle in particular could be the common target of many causes of toxic optic neuropathy, if not all. Agents or their metabolites responsible for the toxicity seem to interfere with the oxidative phosphorylation in mitochondria, causing a buildup of reactive oxidation species, energy depletion, oxidative stress, and activation of apoptosis.

SUMMARY

Further data are still necessary to understand how some of the usual suspects cause damage to the optic nerve or whether they indeed cause damage or not. A basic algorithm, as proposed, could be a useful addition to discriminate the novel causes of toxic optic neuropathy.

VIDEO ABSTRACT

See the Supplemental Digital Content 1 (http://links.lww.com/COOP/A11).

Amiodarone-associated optic neuropathy: a critical review

Although amiodarone is the most commonly prescribed anti-arrhythmic drug, its use is limited by serious toxicities, including optic neuropathy. Current reports of amiodarone-associated optic neuropathy identified from the Food and Drug Administration's Adverse Event Reporting System and published case reports were reviewed. A total of 296 reports were identified: 214 from the Adverse Event Reporting System, 59 from published case reports, and 23 from adverse events reports for patients enrolled in clinical trials. Mean duration of amiodarone therapy before vision loss was 9 months (range 1-84 months). Insidious onset of amiodarone-associated optic neuropathy (44%) was the most common presentation, and nearly one third were asymptomatic. Optic disk edema was present in 85% of cases. Following drug cessation, 58% had improved visual acuity, 21% were unchanged, and 21% had further decreased visual acuity. Legal blindness (<20/200) was noted in at least one eye in 20% of cases. Close ophthalmologic surveillance of patients during the tenure of amiodarone administration is warranted.

Central and Paracentral Visual Field Defects and Driving Abilities

The effect of central and paracentral visual field defects on driving abilities has until now received little attention. To date studies and surveys have concentrated on visual acuity and peripheral field loss. Here we summarise for the first time those diseases causing central visual field defects likely to be associated with binocular visual acuity adequate for driving.

[Bilateral papilledema: prospective study of fifty patients]

In this prospective study, we report fifty consecutive cases of bilateral papilledema without neurosurgical or obvious ophthalmologic etiology, referred to our institution between January 2005 and March 2007. Lumbar puncture with opening CSF pressure measurement distinguished two groups of patients: Group 1 (n=39) with and Group 2 (n=11) without intracranial hypertension. In Group 1, 9/39 patients presented secondary intracranial hypertension mainly due to cerebral venous thrombosis. In 30 patients, after complete investigations, a diagnosis of idiopathic intracranial hypertension was made: as commonly reported, patients were predominantly overweight (96.7% with body mass index>25kg/m2) young (mean age=27.6 years) and women (96.7%). Eleven patients with intracranial hypertension had no headaches. In Group 2, the most common diagnosis was bilateral non-arteritic anterior ischemic optic neuropathy, but rare causes have been identified.

Ischemic Optic Neuropathy: Incidence, Clinical Profile and Long-Term Prognosis in Qatar

Background: Ischemic optic neuropathy (ION) is the most common optic neuropathy in patients over the age of 50 years. It has variable clinical features, prognosis and associated risk factors. As far as we know there are no published data about ION from other Arabic countries.

Objective: We describe the clinical presentation, associated risk factors and the prognosis in patients presenting to our hospital and compare our findings with USA studies.

Methods: In a hospital-based prospective study, consecutive patients with a diagnosis of ION seen between January 2001 and December 2004 were included. Detailed neuro-ophthalmic evaluation, laboratory and neuroradiological investigations were performed in all patients. The patients were followed up at the clinic for mean period of 18 months.

Results: Twenty-six patients, 21 males and 5 females (male to female ratio 4.2:1) were enrolled. Mean age was 50.3years. The incidence was calculated as 1/100,000/year. Anterior ION was the commonest type (88%). Vascular risk factors were common; e. g. diabetes mellitus (DM) (58%), hypertension (HTN) (42%), hypercholesterolemia (10%). Prevalence of disc-at-risk (small or absent physiological cup) was (16%) and of temporal arteritis was uncommon (4%). Brain MRI showed ischemic vascular changes in (29%).

Conclusion: The incidence of ION in Qatar is much less and showed male predominance when compared with data from USA. Anterior non-arteritic ION is the commonest type. Vascular risk factors were more common while prevalence of disc at-risk and temporal arteritis was less compared to USA studies while DM was higher. Therefore, controlling risk factors may reduce the incidence of ION.

Absence of bilateral vision loss from amiodarone: a randomized trial

BACKGROUND

Amiodarone's role as a cause of toxic optic neuropathy is based on case reports. Annual frequency estimates of 0.36% to 2.0%, which have been made without reference to the dose or duration of treatment, are 12 to 200 times higher than those for idiopathic nonarteritic anterior ischemic neuropathy. The object of this study was to determine the incidence, dose, and time until onset of bilateral vision loss from amiodarone as a secondary end point in an investigation of amiodarone's role in preventing sudden death.

METHODS

Randomized subjects received body weight-determined doses of closed-label amiodarone (n = 837) or placebo (n = 832) in a prospective double-masked manner. Closed-label amiodarone subjects were followed, unless death occurred, for a minimum of 27 months. Median follow-up in survivors was 45.5 months. The end point was removal from the study because of bilateral vision loss.

RESULTS

No subject was removed from the study because of bilateral vision loss. Subjects receiving continuous amiodarone for 4 to >60 months at daily doses of >2.0 mg/kg (n = 696), >3.0 mg/kg (n = 559), or >4.0 mg/kg (n = 219) had maximum possible (95% confidence) annual incidences of bilateral toxic vision loss of 0.23%, 0.29%, or 0.74%, respectively. The maximum possible annual incidence rate of bilateral vision loss from amiodarone in all 837 subjects (median age 60 years) receiving a mean daily dose of 3.7 mg/kg (300 mg) was 0.13%.

CONCLUSIONS

At the doses commonly used clinically, bilateral vision loss from amiodarone toxic optic neuropathy occurs infrequently, if at all.

Regression of Bilateral Optic Disc Edema After Discontinuation of Amiodarone

A 54-year-old non-obese woman treated with amiodarone reported blurred vision and had bilateral optic disc edema with relative preservation of visual function. Neurologic examination, brain imaging, and lumbar puncture opening pressures were normal, effectively ruling out increased intracranial pressure. Amiodarone was discontinued and the optic disc edema completely resolved over 15 months. In the absence of alternative explanations for the optic disc findings, amiodarone toxicity is suggested.

Amiodarone and optic neuropathy: the heart of the matter

Amiodarone is one of the most effective antiarrhythmic drugs currently available. Although a subject of intense controversy, a causal link between amiodarone and optic neuropathy has never been firmly established. Indications for treatment with amiodarone are outlined, and features of the optic neuropathy in patients on amiodarone are compared with those of nonarteritic anterior ischemic optic neuropathy. An approach to patients treated with amiodarone who present with optic neuropathy is outlined, and suggestions for a registry and prospective study of such patients are presented.

Unusual and early hyperglycemia following amiodarone infusion in two infants

Amiodarone is an effective antiarrhythmic agent that is widely used for tachyarrhythmias, especially ventricular tachycardia and supraventricular tachycardia. It has some mild short-term (e.g., skin rashes, gastrointestinal symptoms, and corneal microdeposits) and long-term side effects (thyroid dysfunction, visual disturbances, pulmonary infiltrates, ataxia, and hepatitis). We present two infants who had hyperglycemia following amiodarone infusion during the early postoperative period.

Neuro-Ophthalmic Emergencies for the Neurologist

A variety of acute neurologic disorders present with visual signs and symptoms. In this review the authors focus on those disorders in which the clinical outcome is dependent on timely and accurate diagnosis. The first section deals with acute visual loss, specifically optic neuritis, ischemic optic neuropathy (ION), retinal artery occlusion, and homonymous hemianopia. The authors include a discussion of those clinical features that are helpful in distinguishing between inflammatory and ischemic optic nerve disease and between arteritic and nonarteritic ION. The second section concerns disc edema with an emphasis on the prevention of visual loss in patients with increased intracranial pressure. The third section deals with abnormal ocular motility, and includes orbital inflammatory disease, carotid-cavernous fistulas, painful ophthalmoplegia, conjugate gaze palsies, and neuromuscular junction disorders. The final section concerns pupillary abnormalities, with a particular emphasis on the dilated pupil and on carotid artery dissection. Throughout there are specific guidelines for the management of these disorders, and areas are highlighted in which there is ongoing controversy.

Amiodarone optic neuropathy--review

The antiarrhythmic agent, amiodarone (Cordone), Pacerone), has been reported to cause optic neuropathy. However, the clinical manifestations are similar to non-arteritic anterior ischemic optic neuropathy (AION), which makes diagnosing amiodarone optic neuropathy difficult. There is controversy whether or not amiodarone optic neuropathy actually exists as a distinct entity. The clinical manifestations and the proposed pathophysiology of amiodarone optic neuropathy are discussed.

The clinical spectrum of amiodarone-associated optic neuropathy

PURPOSE

To describe the clinical spectrum of amiodarone-associated optic neuropathy.

METHODS

Observational cases series and review.

RESULTS

Of 55 cases, the median interval for onset of optic neuropathy was four months after initiating amiodarone; 88% occurred within 12 months. Seven (13%) patients were asymptomatic. Twenty-two (40%) patients presented with sudden visual loss, while 26 (47%) had insidious loss of vision. Visual acuity ranged from 20/15 to light perception; 10 (18%) patients had legal blindness with visual acuity of 20/200 or worse. Visual field loss was present in 91% of cases. Color vision loss was present in eight (40%) of 20 cases. Optic disc edema was present in 85% of cases, while eight (15%) patients had retrobulbar optic neuropathy, without evidence of disc edema. Optic disc edema resolved over a median time of three months. Five patients had raised intracranial pressure on lumbar puncture.

CONCLUSION

We were able to classify amiodarone-associated optic neuropathy into five clinical categories with respect to temporal characteristics and optic nerve appearance: insidious-onset (43%), acute-onset (28%), retrobulbar (13%), increased intracranial pressure (8%), and delayed-progressive onset (8%). Most cases of optic neuropathy commenced within 12 months of initiating amiodarone, with the median onset being four months. Over 10% of patients will have no visual symptoms at the onset. Ophthalmologic examinations within the first 12 months--and particularly within four months of initiating amiodarone--should improve early detection of amiodarone-associated optic neuropathy.

'White elephants' and a distinguished monkey - or the need for a proactive follow-up in amiodarone therapy

Two patients presented with a rather unusual form and documentation of amiodarone toxicity. General aspects on this topic are addressed with emphasis on neurotoxicity and pulmonary disease. The need for rational prescribing and a scrupulous follow-up is stressed in view of apparent unawareness of general physicians and organ-related specialists alike regarding these very phenomena.

Ischemic optic neuropathies

PURPOSE OF REVIEW

To review recent clinical data on ischemic optic neuropathies, which are some of the most frequently encountered optic neuropathies. These disorders include nonarteritic anterior ischemic optic neuropathy, arteritic anterior ischemic optic neuropathy, and posterior ischemic optic neuropathy.

RECENT FINDINGS

Recent studies have facilitated our understanding of the natural history of visual loss, recovery, and recurrence in these disorders. Additionally, the value of various diagnostic techniques and treatment options, particularly for arteritic anterior ischemic neuropathy, has been clarified.

SUMMARY

Application of the studies described in this paper should allow the clinician to more accurately diagnose ischemic optic neuropathies and counsel the patient with regard to appropriate management, prognosis for visual recovery and future risk of recurrence.