Hi,
Welcome back to icliniq.com. Yes, the right thenar region looks marginally smaller in the picture (attachment removed to protect patient identity). But, if you observe carefully, many of us has right hand thenar region a bit smaller. Regarding amyotrophic lateral sclerosis (ALS), what does not fit in, is the time frame. Fasciculations are produced because of denervation of the muscle. The neuron, which supplies the muscle, is not working from the cell body level of the spinal cord and that is what produces fasciculation in ALS. Fasciculation come as soon as the neurodegeneration of ALS start. Well, for a while let us take the atrophy as a significant one. Atrophy is basically because of long standing (at least two weeks) denervation. So, in almost all the patients the atrophy comes after at least two to three weeks of fasciculations. Now, let us look at the temporal profile of your symptoms. You have fasciculation since last three days and then you noticed thenar atrophy (if we call it atrophy). So, it does not fit into the fasciculation and denervation atrophy, which is seen in ALS. As you already know, the atrophy is either after weakness or after disuse. Now, thenar muscles are very well used for all of us, so you cannot miss weakness neither its disuse atrophy. What I feel is that is a normal variant of asymmetry. I hope you got my point. About ALS, being common in younger women, the prevalence of the disease is just for academic discussions. When it comes to an individual case in clinic, we do not go by the prevalence in either gender.ALS is seen in older age and in male also. I hope you understood the reasons why I think it is not ALS. Fasciculation can be of ALS and can be benign also, an entity called a benign fasciculation syndrome. For almost all the patients with fasciculation due to ALS, it was a retrospective description that the fasciculation is the first symptom to come in ALS. What I mean to say is, they were not diagnosed ALS based on fasciculation alone. ALS was diagnosed only when they developed weakness and atrophy. I think we are very clear about it now. Still, as per standard practice protocol, I told you to keep watch on your symptoms. Please note thatI am telling you to keep a watch and I am not telling you to worry about it all the time. It is very much essential as worry, anxiety and exertion will precipitate the benign non-ALS type fasciculations. So, please avoid being anxious. Next, if your fasciculation persist or progress (I feel they will not) you can get an electromyography of the thenar muscles. If it is ALS, then the electromyography (EMG) would show denervation potentials.