From the Research
Introduction to Fasciculations
Fasciculations are a manifestation of peripheral nerve hyperexcitability, which can occur in various hereditary and non-hereditary diseases 1. They are characterized by brief, spontaneous contractions of muscle fibers, causing a flicker of movement under the skin 2.
Genes Associated with Fasciculations
Several genes have been associated with fasciculations, including those related to:
- Familial amyotrophic lateral sclerosis (FALS) [(1,2)]
- Spinal muscular atrophy (SMA) [(1,3)]
- Bulbospinal muscular atrophy (BSMA) 1
- GM2-gangliosidosis 1
- Triple-A syndrome 1
- Hereditary neuropathy 1
- Spinocerebellar ataxias 1
- Huntington's disease 1
- Rett syndrome 1
- Fabry's disease 1
- Gerstmann-Sträussler disease 1
- Mitochondrial disorders 1
- Muscular dystrophies 1
Pathophysiology of Fasciculations
Fasciculations are thought to derive from ectopic activity generated in the motor system, with a proximal origin contributing to their generation in the early stages of amyotrophic lateral sclerosis (ALS) 2. Distal sites of origin become more prominent later in the disease, associated with distal motor axonal sprouting as part of the reinnervation response 2.
Diagnosis and Treatment
Fasciculations can be a diagnostic feature of ALS, and their presence can help distinguish it from other conditions [(2,4)]. The diagnosis of ALS is often based on a combination of clinical, electrophysiological, and imaging findings. Treatment for ALS typically involves a multidisciplinary approach, including:
Medications
- Riluzole, which can help slow disease progression
- Edaravone, which can help reduce oxidative stress
Supportive Care
- Physical therapy to maintain muscle strength and mobility
- Occupational therapy to assist with daily activities
- Speech therapy to address communication difficulties
- Respiratory therapy to manage breathing problems
Differentials and Caveats
Fasciculations can also occur in benign fasciculation syndrome, which is characterized by fasciculations without weakness, muscle atrophy, or increased tendon reflexes 2. It is essential to differentiate fasciculations from other conditions, such as neuromyotonia, which is characterized by recurrent trains of axonal firing 2. A thorough clinical evaluation, electrophysiological studies, and imaging tests can help establish an accurate diagnosis.