How do doctors determine SFN is NOT ALS or MS?

Hi Mike, Here's some information I found that may offer some help understanding diagnosing ALS vs MS but doesn't mention SFN.

"ALS is characterized by alterations in the patterns seen on electromyography (EMG), while MS patients have a normal study. A lumbar puncture (spinal tap) will show a characteristic pattern with MS that is not seen with ALS."
--- MS vs. ALS: Similarities and Differences - Symptoms: https://www.verywellhealth.com/als-and-ms-symptoms-2440783

SFN vs ALS:
"Can ALS be confused with neuropathy?
Notably, the percentage of misdiagnosis in degenerative LMNS has been reported to be as high as 19%; moreover, up to 10% of patients initially diagnosed as ALS are ultimately re-diagnosed as having another disease, including peripheral neuropathy"
--- The Peripheral Nervous System in Amyotrophic Lateral Sclerosis: Opportunities for Translational Research
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6603245/

Thanks, John! I will check out the articles. Based on what you quoted above, I suppose my EMG would have noted if there was an indication of ALS. Hopefully, the neurophysiologist I will see next week can calm some of my fears. Mike

Hi, From what you report from your testing, the neuropathy seems to be associated with specific spinal nerve roots being compressed. Is your concern arising from symptoms you're having? When our spinal nerves are compressed, they can cause radiculopathy. Those symptoms can easily cause muscle weakness as well as a range of sensory and pain symptoms. Can you say why the podiatrist did the biopsy? Do you also have diabetes? It would not be uncommon for a diabetic patient to acquire a small nerve fiber neuropathy particularly in their feet. When I've had NCS & muscle stimulation tests, I had no nerve compression on-going. It specifically pointed out a different condition which was clearly labeled on the report as a different type of neuropathy. Mine was related to the myelin sheath around the nerves being destroyed. But it was not MS and certainly not ALS. My point being there is a wide range of disorders related to nerves and even with noted disease, the odds of it being some that you fear most are extremely low especially given how your report read. I hope you don't worry too much and I wish you the best.

@sb4ca THANK YOU! Reassuring words mean a lot! I've always been a glass half-empty type, so I tend to go to the worst-case scenario. I am not diabetic. A friend had seen the same podiatrist I was seeing for foot pain. The podiatrist told her she did not think the pain was coming from her foot, but from her back. She referred her for an EMG and it was found that she had nerve compression at L4/L5. She had a fusion, and that solved her foot problem. I saw the same podiatrist for an issue with a toe injury, and after my friend shared her story, I saw the podiatrist again and asked if she could do the skin biopsy and refer me for an EMG... because I had been waiting and waiting to get an appointment with a neurologist... with no luck. The podiatrist did the skin biopsy after I described my foot numbness and burning/tingling. She referred me for the EMG to see if I may still be having some nerve issues in my lower spine that were affecting my feet. I had a 4-level laminectomy L2 - S1 in Nov 2022. It was afterwards that I began to notice the numbness and tingling. All I can make out from the EMG report is that there is still some sort of ongoing issue with the nerves in my lumbar area... perhaps foramenal stenosis or spondylolisthesis. Perhaps, as you say, there is some radiculopathy. My spine surgeon has suggested that a fusion of L4/5/S1 may resolve the issues with my feet... but he is not a neurosurgeon, but an orthopedic spine surgeon and, of course, he can make no guarantee. I do FINALLY have an appointment with a neurophysiologist next week, and I'm hoping that since neurology is his foundation he may be able to guide me further. Though I was pleased the podiatrist agreed to do the skin biopsy and send me for the EMG, she could share with me the reports, but said I needed to see a neurologist for further answers to my questions. She did prescribe Metanx for me, which I took for four months. Two weeks ago my PCP did blood work and included a re-check of my B6 vitamin levels, which were in the normal range six months ago, but came back as too high. So I have now stopped taking the Metanx. I just really feel I need the guidance from neurology.... but it has been SO difficult to get in to see someone. I'm sorry.... I didn't mean to go on and on... enough whining. But I did SO appreciate you taking the time to reach out and offer some comforting words!! Thanks again! Best wishes! Mike

I'm glad I was able to give you some reassurance. I think when you are able to see a neurologist they will conduct the full scope of testing but surely your upcoming appointment will also provide a better understanding of the possibilities. Apparent the biopsy used for the diagnosis are from both the leg and the thigh. Is this what you had done?

The neurologist doing my EMG talked to me about ALS as he was doing the test, because, that was one of my major concerns. He explained that I did not have it right then. Of course, I also got the report.

The skin biopsy was done only above the ankles on each leg. I'm hoping the neurophysiologist will perhaps do some further tests.... and clearly explain the results of the EMG and skin biopsy for me. Thanks again! Mike

Mike, I'm sure you've put yourself on a waiting list/calendar with a good neurology practice, but don't be afraid to check in and see if they've had cancellations. Here in Chicago I was told the soonest a Northwestern-associated neurologist could see me would be late July, so I made that appointment but put in a call to Rush. A cancellation happened to have just come in two days away, so I juggled everything at work and grabbed that appointment. I'm glad I did - the neurologist I saw was impressive and will be doing an EMG/nerve conduction test at Rush in early April.

Ordinarily I would also have had to wait until July to see a neurologist at Rush as well, it was a triumph of sheer dumb luck.

I know how hard it is to wait and worry - the sooner you can get that appointment on the books the closer you are to testing, a diagnosis, and a care plan. Sending you all my very best wishes for reassuring news for you.

@susan0514 Hi, Susan. I was referred to a neurologist by my PCP at my 6-month check in September. They never called me. So a few weeks later, I called to check on the referral and was transferred to voicemail for the scheduling nurse. I left several messages over the next few weeks. I never got any reply. It seems that ALL the neurologists in my area are in this one big group. My referral from the PCP was re-sent in early January... to a different doctor in the practice. As of today, no one has ever called me. There is another practice of neurosurgeons, but I don't need a surgeon.... I don't think so, at least. I finally found a neurophysiologist who has a practice in a smaller city 45 minutes away, and I have an appointment with him next week. I also called Emory in Atlanta about a month ago, and the earliest appointment I could get with a neurologist there was June, so I made that appointment. I don't know if that neurologist deals with neuropathy or if his specialization may be something else. But he was available, so I took the earliest appointment. Sad to have to travel two hours to Atlanta when there is a large practice right here... but if the practice does not even acknowledge a voice mail or a doctor's referral with at least a card to say "Sorry, we are not making appointments for new patients at this time," maybe they are not the practice for me. ;-( I'm glad to hear things worked out differently for you and you were able to get in on a cancellation. I wish. I thank you for your kind message. This Connect support has been amazing!! Best wishes! Mike

Mike, sorry it took so long to get back to you! In Illinois, even with a referral it is usually the responsibility of the patient to call the practice and say I have a referral, are you taking new patients, etc. I understand from a doctor friend that neurologists are one of the most called upon specialties right now, between the needs of an aging population of Baby Boomers and the huge increase of children needing to see neurologists for a wide spectrum of disorders and conditions. I am glad you called Emory, academic medical centers - teaching hospitals - tend to be a part of, or at least up on, new research, protocols, studies, medications, technologies.

I was so lucky with the person who answered the phone that day at Rush. I have no idea what their job title was, but they asked me a lot of questions about my symptoms and prior tests, and when I hesitated to take the appointment because I wasn't sure I could find a sub for my students they went out of their way to urge me to please, please take the appointment. They told me I could cancel if I had to, but if I waited until I had a sub confirmed they guaranteed me the appointment would not still be there. I made the appointment because of that remark, and when I called my boss she immediately agreed I had to take the appointment and they'd manage somehow.

I appreciate this website too. I was so scared when my symptoms started about 15 years ago, and my neurologist at Northwestern first suspected MS or Charcot Marie Tooth. Fortunately for me a genetic test for Charcot Marie Tooth had recently come out at that time - 2009 or 2010 and it was negative, nor were other tests consistent with MS. For a long time my symptoms receded or were quiet, but the last couple of months symptoms have been coming on like gangbusters and it's been a consistent source of anxiety, uncertainty and discomfort and my fears can take me to some dark places. My April tests can't come soon enough!

I really hope we both have an opportunity to find reassurance and answers this spring!