Peripheral nerve hyperexcitability (PNH) disorders are on a spectrum. At one end is benign fasciculation syndrome (BFS), at the other is neuromyotonia (Isaacs Syndrome). Cramp fasciculation syndrome (CFS) falls in the middle.
Before I explain the confusion of CFS with BFS, I'd like to touch on the differences between the different disorders on the PHN spectrum.
Benign fasciculation syndrome: Harmless twitching. It can be irritating if on the face or if very strong when patients are trying to sleep, but it doesn't generally come with pain. Patients may, sometimes, experience paresthesias (pins and needles feelings, shooting pains, cold sensations) and/or mild fatigue, but most don't. Many patients worry excessively that their twitches foretell a more serious disorder like amyotrophic lateral sclerosis (ALS, also known as Lou Gehrig's disease). EMGs are negative or show fasciculations only.
Cramp fasciculation syndrome: Harmless twitching (twitching may be very strong and may undulate) and cramps that may be painful, and usually some combination of the following: muscle stiffness, paresthesias, fatigue, and exercise intolerance. Health anxiety is not an issue. Most of the research I've found says that EMGs are negative or show fasciculations only, but my doctors say EMGs can show more if they are still considered nonspecific.
Neuromyotonia: All of the symptoms of cramp fasciculation syndrome, with the additional symptoms, for some, of excessive sweating or delayed muscle relaxation. Health anxiety is not an issue. EMGs have "multiple high-frequency waveforms."
Cramp fasciculation syndrome is sometimes referred to as benign cramp fasciculation syndrome (BCFS) by both doctors and patients. It is not uncommon to hear patients, especially those with BFS, refer to it as "BFS with cramping." (It's important to note that, as concerns both BFS and what is sometimes called BCFS, "benign" refers only to the fact that the condition will not lead to a fatal condition [though with CFS there is some disagreement on this point, with some researchers considering the development of a motor neuron disease an extremely rare but sometimes possible outcome]; it does not in any way imply that the conditions cause no disability.) However, referring to CFS as "BFS with cramping" is misleading and, I think, completely undermines the experiences of those with CFS.
Many researchers are inclined to point out that the main difference between CFS and neuromyotonia often lies in EMG results only. This link, to an article written by several experts in the field, explains this more clearly.
I said in the introduction that I'd be mentioning a little more about my own symptoms. Since the progression of my symptoms helps make my point, this seems like a good time.
I have all of the symptoms associated with CFS, as well as the sweating associated with neuromyotonia. Twitching and cramping, while they occur frequently, are the least bothersome to me. In fact, my first symptom was muscle tightness. It goes back many years further than the year I consider the start of my symptoms; I don't count back that far primarily because I was always a very active person and don't know exactly how much of my muscle tightness during those years can be attributed to my lifestyle and how much can be attributed to this disorder. I do know when I began to feel as though I was pulling muscles for no reason, so that is the year I use when doctors ask me when my symptoms first began. I had already begun to experience extreme fatigue and some paresthesias long before (as in years) my twitching and muscle cramping even began. Frankly, I think it minimizes everything I've gone through when I hear others speak of this disorder as one of possibly irritating twitching with some cramping thrown in.
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