Neurology International 2014; volume 6:5208 Another perspective Introduction Correspondence: Marco Antonio Araujo Leite, on fasciculations: Fluminense Federal University – UFF Niterói, Rio when is it not caused The fasciculations can be defined as visible de Janeiro, Brazil. by the classic form fast, fine, spontaneous and intermittent con- E-mail: [email protected] tractions of muscle fibers. Some neurologists of amyotrophic lateral sclerosis call them verminosis, because they look like Key words: fasciculations, neurological diseases, electromyography treatment. or progressive spinal atrophy? worms moving below the dermis.¹,² Undoubtedly, this finding in a neurological Contributions: the authors contributed equally. Marco Antonio Araujo Leite, examination is of concern, given its close rela- ¹ Marco Orsini,1 Marcos R.G. de Freitas, tionship with amyotrophic lateral sclerosis Conflict of interests: the authors declare no João Santos Pereira,1,2 ¹ (ALS), a disease that leads to a depletion of neu- potential conflict of interests. Fábio Henrique Porto Gobbi,3 rons in the fore tip and the pyramidal bundle. Received for publication: 29 November 2013. Victor Hugo Bastos,4 The presence of fasciculations, however, is not a sign of ALS when no other symptoms or signs Accepted for publication: 28 March 2014. Dionis de Castro Machado,4 of involvement of the fore tip and the pyramidal Sergio Machado,5 Oscar Arrias-Carrion,6 This work is licensed under a Creative Commons bundle are identified.³ No one knows whether Jano Alves de Souza, Acary Bulle Attribution NonCommercial 3.0 License (CC BY- the origin of ALS is central, in the first or sec- NC 3.0). Oliveira7 ¹ ond motor neurons, in the peripheral, or even in Neurology Service, Movement Disorders the terminal motor nerve − which is an even ©Copyright M.A.A. Leite et al., 2014 Unit,¹ Fluminense Federal University, more intriguing aspect for experts. In short, it is Licensee PAGEPress, Italy incorrect to associate fasciculations directly to Neurology International 2014; 6:5208 Niterói, Rio de Janeiro, Brazil; doi:10.4081/ni.2014.5208 Neurology Service, Rio de Janeiro the injury of fore tip of the spinal cord, because the skeletal pathophysiological involvement can University,² Brazil; 3Neurology be quite broad.3,4 Department, São Paulo University, Brazil; Potential fasciculations may also persist after only 4 Methods Departament of Physiotherapy, Piaui a distal nerve block. This suggests that fascicu- Federal University, Parnaíba, Brazil; lation potentials may originate anywhere in the We reviewed several articles using the fol- 5Physical Activity Neuroscience, Physical axon, probably within the distal axonal arboriza- lowing databases: Lilacs, Scielo, Medline and Activity Sciences Postgraduate Program, tion. However they are known to be associateduse Pubmed. In our search we used the following Salgado de Oliveira University, Niterói, with a hypersensitivity of denervated muscles. It keywords: fasciculations, epidemiology, etiolo- Brazil; 6Movement Disorders and Sleep is also important to consider that several condi- gy, benign fasciculations syndrome, exercises, tions may trigger them, such as other diseases Unit, General Hospital Dr. Manuel Gea amyotrophic lateral sclerosis, motor neuron of the fore tip of the spinal cord (benign González, Secretaria de México D.F., diseases, neuromuscular diseases, movement monomelic amyotrophy, progressive spinal México; 7Neurology Service, São Paulo disorders, drugs, poisoning, physical activity muscular atrophies, Hirayama disease and oth- Federal University, São Paulo, Brazil and their correspondents in Portuguese, ers), neuromuscular junction disorders, elec- Spanish, Japanese in the period between 1940 trolyte disorders, systemic diseases and use of and 2013. certain medications.5 Also healthy individuals Abstract can have fasciculations, although they are gen- erally located in well-defined sites, such as the brachial distal third, the crural area and the eye- Fasciculations are visible, fine and fast, Fasciculations in healthy lids.¹ With regard to fasciculations potentials sometimes vermicular contractions of fine induced by drugs, Masland and Wigiton,6 in a subjects muscle fibers that occur spontaneously and pioneering experimental study, concluded that intermittently. The aim of this article is to dis- neostigmine can cause fasciculation potentials Fasciculations can also be found in individ- cuss the main causes for fasciculations and Non-commercialby increasing the concentration of acetylcholine uals with no neurological disease. In 1963, their pathophysiology in different sites of the at the neuromuscular junction in felines. Reed and Kurland warned that the presence of central/peripheral injury and in particular to Discharges are caused by the direct effect of fasciculations was not necessarily a prelude to disprove that the presence of this finding in acetylcholine in the motor nerve terminals. A the onset of a progressive and lethal disease, the neurological examination is indicative of similar mechanism also occurs during induc- due to the involvement of the lower motor neu- amyotrophic lateral sclerosis. Undoubtedly, tion of anesthesia with succinylcholine endotra- ron.8 Since then, several authors have most fasciculations have a distal origin in the cheally.7 Orsini et al.5 reported the case of a explored this topic, defining a benign fascicu- motor nerve both in normal subjects and in young man with benign fasciculations, trig- lation syndrome (BFS), that most frequently patients with motor neuron disease. Most of gered by the use of oral corticosteroids adminis- affects young healthcare professionals,9,10 them spread to other dendritic spines often tered in immunosuppressive doses in patients who, in some cases, have already developed producing an antidromic impulse in the main with immune-mediated kidney disease, which dyspnea.11 An interesting Australian prospec- axon. The clinical and neurophysiological subside completely after medication tapering. tive study published recently examined the diagnosis must be thorough. It may often take The objective of this study based on the cur- cases of 20 physicians (20 consecutive cases) long to record fasciculations with electroneu- rent literature is to describe various causes of complaining of fasciculations.9 Fourteen of romyography. In other cases, temporal moni- fasciculations and to discuss the pathophysio- them were very concerned about being diag- toring is necessary before the diagnosis. The logical skeletal involvement, when present nosed with ALS. The fasciculations were main- treatment, which may be adequate in some (Table 1). ly in the lower limbs, which had normal muscle cases, is not always necessary. strength. In the electrophysiological study, fas- [Neurology International 2014; 6:5208] [page 47] Review ciculations potentials were of the simple type, al.18 observed fasciculations in half of patients, Montagna et al.²4 reported fasciculations motor conduction was normal and no signs of most commonly in the facial region. Potential and amyotrophy in five cases of Shy-Drager denervation or neurogenic changes of motor fasciculations were noticed in conventional syndrome. Clinical, electrophysiological, and units were apparent. electromyography in 41 cases. The authors anatomopathological examinations indicated These authors, in agreement with others, reported the involvement of the peripheral the degenerative involvement of spinal previ- concluded that physical exercise, stress, nerves. ous ends. fatigue and caffeine abuse can precipitate or Kanai and Kuwabara posited that in SCA 3 In 2008, Luo et al.25 described the case of a aggravate this picture. Among the other six the severity of cramps/fasciculations correlates 68-year-old man, whose manifestations were individuals in the sample, five patients mani- with peripheral axonal excitability,19 suggest- muscle weakness, amyotrophy, fasciculations, fested a cramp-fasciculation syndrome ing that the appearance of potentials is associ- tremor and cerebellar syndrome. The ENMG (Denny-Brown syndrome) and only one suf- ated with subjacent axonal peripheral deple- was consistent with spinal muscular atrophy fered from ALS. tion and attempted sprouting of the remaining (SMA) and olivopontocerebellar atrophy Some authors have stated that, in order to motor neurons for reinnervation of partially (OPCA), a type of MSA, which was confirmed establish the clinical diagnosis of BFS, a mini- denervated muscles. Another cerebellar degen- by the MRI results. As there were no other mum of five years is necessary, due to the evo- eration in which the ataxia is associated with cases in the family of the patient, the authors lution, in some cases, of the motor neuron dis- fasciculations is SCA 36. Recently described in reported this to be the first case of SMA with ease.12-14 Japanese families by Kobayashi et al., it is sporadic OPCA. Unlike fasciculations, these A work by Fermont et al.15 reported the characterized by an increasing expansion of are more frequent in patients with MAS, prevalence and distribution of fasciculations the hexanucleotide GGCCTG repeat in the first myoclonus, myokymia, and involved particular- in healthy adults. The potentials were studied intron of the NOP56 gene.20 ly the face.26 by ultrasound in 58 individuals from different Ikeda et al.21 found that amyotrophy and fas- Machida et al.²7 reported a case of sporadic age groups. The subjects were also interviewed ciculations affected the tongue of most