On forums dedicated to ALS (Charcot/Lou Gehrig's disease), there are often messages from people asking if their symptoms are reminiscent of those of ALS. In general, the authors of these messages experience fasciculations, which when you don't know, is relatively disturbing (fasciculation anxiety syndrome).
Fasciculations are discrete, rapid, repetitive, painless, and localized muscle contractions of the limbs that often occur in isolation or can be associated with muscle cramps. When my uncle was affected by ALS, I briefly saw certain muscles in the thigh twitch, which was distressing. I suppose it was a psychological effect. In any case, fasciculations are not specific to ALS and should not be confused with the phenomenon of clonus. Skeletal muscle cramps are a distinct phenomenon characterized by sudden, involuntary, painful muscle contractions lasting from seconds to minutes and relieved by voluntary extension of the limbs.
The cramp-fasciculations syndrome, which combines these two phenomena, is a benign and usually short-lived disorder without the development of muscle weakness or atrophy. The syndrome is rare, affecting less than 1% of the population and more women than men.
Muscle cramps, fasciculations, and myokymia result from hyperexcitability of peripheral nerves. Muscle contractions and spasms occur in hypothyroid myopathy, and pregnancy can reveal various subclinical neuromuscular disorders, including amyotrophic lateral sclerosis (ALS). It can also be due to ingesting various foods or dietary supplements.
A recent study reports cases of transient diet-related cramp-fasciculations syndrome linked to excessive ingestion of monosodium glutamate or white lupin seeds. These cases illustrate the health hazards of some popular dietary practices.
The first group of patients experienced acute headaches, flushing, muscle stiffness, and fasciculations after consuming umami-flavored foods containing high concentrations of monosodium glutamate. Monosodium glutamate has been used for over 100 years to flavor foods. Monosodium glutamate is harmless for human consumption as a flavor enhancer. However, it is prudent to limit its consumption to a few grams.
Source: Jean-Claude ECHARDOUR
The second group of patients consuming foods derived from lupin seeds developed acute cholinergic toxicity, the cramp-fasciculations syndrome, and, with chronic consumption, significant, self-limiting, but incompletely reversible deficits of the upper and lower motor neurons! White lupin is mainly used as an appetizer, but it is toxic, to prepare it it must be soaked in cold salted water, after cooking, for a week, changing the water twice a day. They are sold canned, vacuum-packed, or in brine.
While the symptoms appear to have been short-lived in both cases, this is not always the case. The medical literature describes a case, where a 28-year-old woman who had consumed 3 grams of lupin seeds per month for 8 years, presented symptoms very similar to ALS. Twenty months after stopping lupin seed ingestion (probably L. albus), she was neurologically stable but had pyramidal signs, weakness, and amyotrophy in all four extremities. Fasciculation was no longer present, dysarthria had improved, and dysphagia had resolved.