Hydroxychloroquine Toxicity and Screening

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Identifier Hydroxychloroquine_Toxicity_and_Screening
Title Hydroxychloroquine Toxicity and Screening
Subject Hydroxychloroquine toxicity, Bulls-eye Maculopathy, Plaquenil
Creator Andrew G. Lee, MD, Chairman, Department of Ophthalmology, The Methodist Hospital, Houston, TX; Professor of Ophthalmology, Weill Cornell Medicine; Lauren Nakhleh, Baylor College of Medicine Class of 2023
Description Dr. Lee lectures medical students on hydroxychloroquine toxicity.
Transcript So, we are going to cover hydroxychloroquine toxicity. Hydroxychloroquine is also known as Plaquenil. And we are screening patients for hydroxychloroquine toxicity. The toxicity is a bull's-eye maculopathy, but basically, we never want to see the bulls-eye. We want to recognize the toxicity and stop the medicine before the development of the bulls-eye because that is permanent damage to the retinal pigment epithelium and can result in irreversible vision loss. The key things that we want to know in the screening strategy is how much risk are we dealing with and the risk is determined by patient-related factors and then drug-related factors. The patient-related factors are age and older patients. We should follow them more closely at 65 or older. Obesity and their weight even though that's being de-emphasized now. Their renal function and their liver function because that's how the drug is excreted. And then we want to talk about factors that are related to the drug. The drug related factors are the dose and in older literature 6.5 milligrams per kilogram was considered the risk threshold, but then you had to adjust for the weight and ideal body mass. So now we just say 5 milligrams per kilogram is kind of our new threshold dose. We want to know the duration and the longer you've been on it the more likely you are to get the toxicity. And the cumulative dose which is one kilogram of drug. So, if we've been on the drug for longer than five years we are already starting to think about toxicity. The toxicity rarely occurs before five years and so really, we shouldn't be worried about it until year five, but you're going to screen the patient more aggressively after five years. And after ten years to 15 years your risk is going up a lot. So, it's kind of becoming a linear risk and by 20 years maybe up to 20 percent of the people are going to have risk of toxicity. So, dose, duration, and cumulative dose are all super important. We would like to know if you have previous macular disease so I tend to recommend against hydroxychloroquine in patients who have pre-existing maculopathy like age-related macular degeneration or who can't do the tests like kids or really old people. And if they are on any other drugs but especially tamoxifen. That is a really dangerous thing. And you need to know that Asian people are more likely to have a peri-axial form of the disease, a peripheral form. And so even though we recommend doing a 10-2 visual field for screening we might to a combination of a 24 and a 10-2 in an Asian patient because they're more likely to have peripheral field lines. The screening strategies once you decide that someone is a high-risk patient is that we have to do tests. So yes, we're going to talk to the patient and ask them about their vision. And then tests we're going to do are the Humphrey visual field and we're going to be testing the central field, so we want a 10-2 and not a 24-2 unless they are the Asian patient. We want to do an OCT and we want to do a spectral-domain OCT of the macula and not a time-domain OCT. So, this side is the yes side and this side is the no side. We want to do a multifocal ERG if we have it, but we don't really want to have a full field ERG because that is not as good. We are going to do fundus autofluorescence and we're not going to do a fluorescein angiogram. It is the combination of these tests that is how we screen patients. So normally we need a field of some kind. We givepatients an Amsler to take home, but we don't use that in the clinic, we use the 10-2. We are going to do a spectral domain OCT of their macula and we are going to do an MERG or a fundus autofluorescence, so a field plus one of these three is probably reasonable. You don't have to do all three, but you have to do something. And we are not going to do the 24-2, the time domain OCT, or a full field ERG of fluorescein for screening. The rest of the exam is like a normal eye exam for patients who are on hydroxychloroquine.So, in summary, in patients who are on hydroxychloroquine we need to make a risk stratification but the highest predictors of risk are dose, duration, cumulative dose and whether they have concomitant renal and liver dysfunction or just starting to get over a kilo of cumulative dose above 6.5 mg/kg or a duration greater than 5 years. You really should be considering that person a high risk. You should worry if they are on concomitant Tamoxifen, if they have pre-existing macular disease, and have a slightly different strategy for Asians 24 vs 10-2. You have to do a field, a 10-2, but not a 24-2. An OCT spectral-domain of the macula but not a time-domain OCT. An MERG but not a full field ERG. And a fundus autofluorescence but not a fluorescein angiogram. You need to do a field plus something else. I usually use OCT. And if you do that, we can prevent the patient from having a bulls-eye maculopathy and a hydroxychloroquine toxicity.
Publisher Spencer S. Eccles Health Sciences Library, University of Utah
Type Image/MovingImage
Format video/mp4
Rights Management Copyright 2020. For further information regarding the rights to this collection, please visit: https://NOVEL.utah.edu/about/copyright
Holding Institution Spencer S. Eccles Health Sciences Library, University of Utah, 10 N 1900 E, SLC, UT 84112-5890
Collection Neuro-ophthalmology Virtual Education Library: NOVEL http://NOVEL.utah.edu
ARK ark:/87278/s6sb9r2h
Setname ehsl_novel_lee
Date Created 2020-06-22
Date Modified 2020-08-05
ID 1578870
Reference URL https://collections.lib.utah.edu/ark:/87278/s6sb9r2h
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