Progress in the Treatment of Amyotrophic Lateral Sclerosis (ALS) - Episode 10
Key opinion leaders consider the importance of respiratory care in ALS by discussing immunization against respiratory illness as well as the use of non-invasive ventilation.
Richard S. Bedlack, MD, PhD, MS: Ammar, with many of my patients, after they see their primary care doctor for an annual checkup, they email me and they say, “My doctor wants to start this medicine” or “They want me to get this immunization. Should I do it? Is it going to affect my ALS [amyotrophic lateral sclerosis]?” Are there medications that patients with ALS should not take? Is it OK for them to get immunizations like the flu shot and maybe the COVID-19 vaccine?
Ammar Al-Chalabi, MB, ChB, PhD: There are some medicines that patients with ALS cannot access. For example, in Europe and in the United Kingdom, we cannot access dextromethorphan and quinidine. For pseudobulbar affect, we have to use antidepressants. In terms of medications that somebody should not take, it is largely around treatments that might interact with their existing medication, and I suppose treatments that could worsen existing symptoms, such as weakness. Those are usually obvious. The kinds of things that are going to worsen current symptoms are usually obvious.
In terms of immunization, it is important for somebody with ALS to stay up to date with their immunizations. The reason is that diaphragm weakness can occur early, so even if the person does not have symptoms, some studies have shown that up to 80% of people, right at diagnosis, have some diaphragmatic involvement even at that early stage. Of course, that makes it more difficult to clear chest infections. Most immunizations are against influenza or COVID-19, for example. They are meant to prevent respiratory infections. You are more likely to get a secondary bacterial pneumonia if you do not clear that. Immunization is important for that reason, particularly for somebody with a weak diaphragm.
Richard S. Bedlack, MD, PhD, MS: Thank you. We have only briefly mentioned noninvasive ventilation [NIV]. Jeremy, tell us a bit more about noninvasive ventilation. How do we screen people for that? How do we decide when to start it? What do we start? What are the benefits?
Jeremy M. Shefner, MD, PhD: Noninvasive ventilation refers to a system that is interfaced with the patient using a mask or sometimes with a tube that they can sip on. In general, it most commonly refers to something called bilevel positive pressure ventilation, which means that there is air blowing out of the mask or the tube at all times, and it is triggered to the patient’s breaths. When a patient begins an inhalation, the pressure increases and allows them to fill their lungs to a greater degree than they could without it. When they stop their inhalation and begin to breathe out, the pressure declines, allowing them to breathe out more easily as well.
It mimics a ventilator for somebody who is intubated, in that the pressure increases, causing expansion of the diaphragm, and it then releases, causing a passive reduction in the volume of the lungs. It is effective for most patients with ALS who have good bulbar control. Patients who have difficulty controlling their lips or mouth or who are quite spastic in their face often have significantly more challenges in adapting to this. There are multiple studies that suggest that, when NIV is adopted at some point, it increases survival and increases quality of life, especially sleep.
There are third-party payer guidelines that give you suggestions of when it is appropriate. In general, in the United States, it is a vital capacity less than 50% of predicted, or a negative inspiratory force less than 50% as well. These are number guidelines, but for me, I institute it when the patient history suggests that there is any kind of respiratory insufficiency that needs care. In particular, this is anybody who is having difficulty lying down to sleep, anybody who wakes up short of breath, anybody who wakes up with a headache, and anybody who feels short of breath during the day and feels like they have to stop what they are doing and just sit there.
There are standards that are more stringent than that, and they suggest that, at least in some cases, many people believe that any measurable respiratory deficit down to about 80% of normal forced vital capacity should mandate the institution of noninvasive ventilation. I have tried that in the past, but I have found that compliance is usually fairly poor. I have never been convinced that that in itself improves quality of life when it is instituted then. My thresholds may not be the same as they are for other people, but my decision is predominantly symptom-based. When somebody has a symptom that I think I can treat with that, and I have listened to them, then that is when I do it. I do not tend to do it prophylactically.
Richard S. Bedlack, MD, PhD, MS: Is that the same for you Ammar and for you Jinsy? Is it symptom-based?
Jinsy A. Andrews, MD, MSc: Ammar should comment because the criteria are a bit different than they are in the United States. For Jeremy and I, particularly for me, a patient has to come below half of their lung capacity, or 50% of their predicted value for forced vital capacity, to be eligible for the payer to pay for the noninvasive ventilator if we order it. I can sometimes get it if they are not that low, but if they are very symptomatic. Those symptoms can be morning time headaches, poor sleep quality, or daytime somnolence, feeling sleepy. I know that it is different in other regions. Ammar, maybe you can speak to the experience of trying to initiate it earlier and the criteria there.
Ammar Al-Chalabi, MB, ChB, PhD: We use guidelines called the NICE [National Institute for Health and Care Excellence] guideline, which is an algorithmic process. It requires a lower threshold. If someone is symptomatic, you institute it earlier, and if they are not symptomatic, then you institute it later. Our vital capacity threshold is 70% generally, but also, if you cannot measure vital capacity, you can use oxygen saturation, or you can use sniff nasal inspiratory pressure within the guideline as well. It is a complicated algorithm, but it is what we use. It is really the same as it is for Jeremy and Jinsy: it is symptom-based, in fact.
Richard S. Bedlack, MD, PhD, MS: Thank you for watching this NeurologyLive® Peer Exchange. If you enjoyed the content, please subscribe to our e-newsletters to receive upcoming Peer Exchanges and other great content right in your inbox.
Transcript Edited for Clarity