Autonomic Function Testing

Additional Info

• Segment Number:3
• Audio File:uab/1636ua2c.mp3
• Doctors:Kazamel, Mohamed
• Featured Speaker:Mohamed Kazamel, MD
• CME Series:Medical Innovations
• Post Test URL:https://cmecourses.som.uab.edu/mod/quiz/view.php?id=3878
• Guest Bio:Mohamed Kazamel, MD is a neurologist at The Kirklin Clinic of UAB Hospital. 
  
  Learn more about Mohamed Kazamel, MD 
  
  Release Date: 5/4/2020
  Expiration Date: 5/4/2020
  
  Disclosure Information:
  Dr. Kazamel has the following financial relationships with commercial interests:
  
  Consulting Fee – Akcea Therapeutics; Bio Stealth Therapeutics
  
  Dr. Kazamel does not intend to discuss the off-label use of a product. No other speakers, planners or content reviewers have any relevant financial relationships to disclose.
  There is no commercial support for this activity.
• Transcription:Melanie Cole (Host): Modern autonomic function tests can noninvasively evaluate the severity and distribution of autonomic failure. My guest today is Dr. Mohamed Kazamel. He is an Assistant Professor in the Division of Neuromuscular Disease in the Department of Neurology at UAB Medicine. Welcome to the show, Dr. Kazamel. Let's start with the grouping of the autonomic disorders that we are discussing here today.
  
  Dr. Mohamed Kazamel (Host): Thanks, Melanie, for having me. In fact, the autonomic disorders that we are able to test for are divided into different categories, which include disorders of maintenance of the blood pressure like orthostatic hypertension and the famous postural orthostatic cardio syndrome, which is referred to as POTS. We also try to test for growing disorders of the peripheral nervous system called “small fiber neuropathy”. And, small fiber neuropathy happens when a patient comes to our office complaining of tingling or burning sensation in their feet and we perform the regular routine nerve conduction studies on them and these studies come back normal. So, there is no effective way of evaluating the small fiber neuropathies other than performing autonomic function testing on them and also performing skin biopsy. The third category of the autonomic dysfunction diseases include the central neuro degenerative diseases like multiple system atrophy and the different Parkinson's plus syndromes. These disorders manifest with the movement disorders; the tremors, the dementia and all of this. They also present with dysfunction in the autonomic functions. Oftentimes the patients with multiple system atrophy, they develop significant hypotension and orthostatic intolerance when they stand up. And, they cannot be distinguished that much from advanced Parkinson's disease patient, because in advanced Parkinson’s you have the same hypotension and also the treatments that are used for Parkinson’s to lower the blood pressure. So, we need different autonomic function testing to differentiate severe neuro degenerative disease, multiple system atrophy from just a Parkinson’s disease case.
  
  Melanie: What other symptoms would present with a patient that would indicate the autonomic testing?
  
  Dr. Kazamel: So, symptoms that indicate autonomic testing, again, if the patient has painful burning sensation in their feet or they have tingling sensation while we perform the nerve conduction study and find them normal, then they have to referred for autonomic function testing. Also symptoms of orthostatism in general, like inability to maintain the blood pressure after standing. These patients start developing symptoms of cerebral hypo-perfusion like headaches, dizziness, giddiness, blackouts, pain between the shoulder blades and some of them also develop symptoms of adrenergic activation like feeling of heart beat racing, chest pain, tremors, increased anxiety, all of these.
  
  Melanie: And, if they present with some of these symptoms you have discussed, what are some of the tests that you are using now, Dr. Kazamel?
  
  Dr. Kazamel: So, the five standardized autonomic function tests that we use here in the lab include, first the QSART or the commercially available option, which is called a Q-sweat. QSART stands for quantitative sudomotor axonal reflex testing and this test measures the sweat response in different parts of the body, including the forearm, the proximal leg, the distal leg and the foot. So, what we do is that we stimulate the skin sweat glands with iontophoresis of acetylcholine and we measure the sweat response from these areas. And depending on which areas in the body that do not produce too much sweat, we defined what is the distribution of the small fiber neuropathy. We also do the heartrate response to deep breathing and this is one of the most sensitive testing for evaluation of the vagus nerve function. What we do is we ask the patient to breath heavily for six or seven cycles and then we evaluate their heart rate while they are breathing heavily. We average the mean difference between the maximal heartrate and the minimal heartrate and if that means difference decrease, that is an early sign of vagal neuropathy. We also do the Valsalva maneuver, where we try to record the heartrate and blood pressure response to patients when they strain. During the Valsalva maneuver what we do principally is have them forcibly exhale through a bugle, generating a 40 millimeter mercury forcing expiratory pressure for 15 seconds, which is very laborious job. We try to generate a curve of how their blood pressure and their heartrate respond to that. We also do the head-up tilt table testing and we measure the blood pressure for the patient while they are supine and then we tilt them over for three seconds to an upright 70 degrees angle, and we leave them in that position for like 10 minutes and we record how their blood pressure and heartrate respond to that. Our final test is a very unique test which is a thermoregulatory sweat test and in the last test, we depend on a certain type of powder called Alizarin S Powder, which has a unique character of changing its color when it gets exposed to sweat. So, what we do is we bring the patient, dust them all over the body with this powder - and the powder while its dry, its yellow in color and when it gets wet with sweat, it changes its color to purple. And then, after we dust the patient with this powder, we insert them into what's called the autonomic chamber and try to raise their core temperature only one degree, from 37 centigrade to 38. And, as they start to sweat, the powder changes its color and that tells us which part of their body does not sweat and certain patterns on that test leads to different diseases. So, these are the five different modalities of testing that we perform in the autonomic function testing lab.
  
  Melanie: Dr. Kazamel, when you are using the tilt table and doing Valsalva, are there certain medications that you'd like your patients to not take that day of the testing that might interfere with sweating before the test?
  
  Dr. Kazamel: Well, that's a very, very important question. So, certain over the counter medications like allergy medications, the anti-histamine medications like the Benadryl, for instance. We try to ask our patients not to take them in the 48 hours before testing, because these medications have anticholinergic properties and they decrease the amount of sweating. So, they interfere with our testing. Other medications that we ask the patients to stop, too, like the alpha agonist including the prostate medications and the beta blockers. However, for the beta blockers that are used in treatment of hypertension or cardiac dysrhythmias, we are sometimes able to leave that to the discretion of the prescribing physician because stopping those medicines, even for 24 hours, can be a problem for the patient. So, these are the three or four different categories of medications that we would like the patient to stop before performing the test. Also, we would like them not to smoke or drink caffeine within the last three hours before testing and we would like them not to drink alcohol on the night before testing.
  
  Melanie: And, for more information about testing results and making a differential diagnosis, you can visit uabmedicine.org/learnneuro. And, then, in just the last few minutes Dr. Kazamel, how can a community physician refer a patient to UAB Medicine?
  
  Dr. Kazamel: So, we are working currently on our website that has a link that the community physician can fill out a form and fax it over to us in the Neuromuscular Diseases Division. Also, they can call our office at UAB Neuromuscular Disease Division for referrals.
  
  Melanie: And, tell us about your team. Why is UAB so great to work with?
  
  Dr. Kazamel: Well, UAB has a lot of potential across. We here have very large department of neurology that includes more than 65 physicians and scientists in different categories in sub-specialties of neurology. And, we all collaborate with each other to provide the excellent standard of care to our patients. On the other side, we also have major collaborations in research and we believe that the autonomic function testing lab will provide excellent service to our patients and to our community physicians in different aspects. We expect referrals to come from neurologists, we expect referrals to come from cardiologists and family physicians and interns.
  
  Melanie: Thank you so much for being with us today, Dr. Kazamel. You are listening to UAB Medcast. For more information on resources available at UAB Medicine, you can go to www.uabmedicine.org/physician. That's www.uabmedicine.org/physician. This is Melanie Cole. Thanks so much for listening.
  
  
  
• Hosts:Melanie Cole, MS