What causes swallowing muscle atrophy?

From the Guidelines

Swallowing muscle atrophy is primarily caused by aging, neurological disorders, prolonged disuse, and certain medical conditions, with the most significant risk factors being stroke, Parkinson's disease, multiple sclerosis, and ALS, as supported by the ESPEN guideline on clinical nutrition in neurology 1. The causes of swallowing muscle atrophy can be multifaceted, including:

• Aging (presbyphagia), which leads to natural muscle loss throughout the body, including the swallowing muscles
• Neurological conditions, such as stroke, Parkinson's disease, multiple sclerosis, and ALS, which directly impact nerve signals to the swallowing muscles, leading to weakness and atrophy
• Prolonged disuse, such as during prolonged intubation or tube feeding, which can cause disuse atrophy
• Certain medical conditions, including head and neck cancers and their treatments (radiation therapy and surgery), which may damage swallowing structures
• Inflammatory conditions, such as myositis, which can directly attack muscle tissue
• Medications with anticholinergic effects, which can reduce saliva production and indirectly contribute to muscle weakness According to the ESPEN guideline, oropharyngeal dysphagia is a common feature of many neurological disorders, and its prevalence is high in patients with stroke, Parkinson's disease, multiple sclerosis, and ALS 1. The guideline also highlights the importance of early intervention with a speech-language pathologist to maintain swallowing function and prevent complications like aspiration pneumonia 1. Treatment approaches depend on the underlying cause and may include swallowing therapy exercises, medication adjustments, and in some cases, surgical interventions. Neuromuscular electrical stimulation (NMES) has been shown to improve swallowing function in patients with oropharyngeal dysphagia of different etiologies, and its use is recommended as an adjunct to behavioral swallowing treatment 1.

From the FDA Drug Label

Treatment with botulinum toxin products, including JEUVEAU, can result in swallowing or breathing difficulties. Patients with preexisting swallowing or breathing difficulties may be more susceptible to these complications In most cases, this has been a consequence of weakening of muscles in the area of injection that are involved in breathing or oropharyngeal muscles that control swallowing or breathing Dysphagia may persist for several months, and require use of a feeding tube to maintain adequate nutrition and hydration.

The cause of swallowing muscle atrophy is weakening of muscles in the area of injection that are involved in breathing or oropharyngeal muscles that control swallowing or breathing, which can be a consequence of treatment with botulinum toxin products, including JEUVEAU 2.

From the Research

Causes of Swallowing Muscle Atrophy

• Swallowing muscle atrophy can be caused by various neurological disorders, including amyotrophic lateral sclerosis (ALS), Parkinson's disease, and myasthenia gravis 3.
• Stroke is also a common cause of dysphagia, which can lead to swallowing muscle atrophy 3.
• Muscular diseases such as oculopharyngeal dystrophy, Steinert myotonic dystrophy, and mitochondrial myopathies can also cause swallowing disorders and muscle atrophy 4.
• Motor neurone disease, including bulbar palsy and progressive muscular atrophy, can also lead to swallowing difficulties and muscle atrophy 5.

Underlying Mechanisms

• Decreased pharynx peristalsis and impaired upper esophageal sphincter (UES) relaxation are major pathological features found in patients with swallowing muscle atrophy 4.
• Pharyngeal function is a major prognostic factor in patients with swallowing muscle atrophy, and cricopharyngeal myotomy can be an effective treatment in some cases 4.
• Tongue muscle deficits and chewing deficits are also associated with dysphagia and swallowing muscle atrophy in patients with ALS 6.

Clinical Findings

• Patients with swallowing muscle atrophy may experience weight loss, pulmonary infections, and modified food consistency 4.
• Videofluoroscopy, pharyngoesophageal manometry, and videofibroscopy can be used to assess the different stages of deglutition and diagnose swallowing muscle atrophy 4.
• Fiberoptic swallowing evaluation is a useful tool for detecting swallowing deficits and laryngeal sensitivity in patients with ALS 6.