Understanding Dysphagia in Myasthenia Gravis - Causes, Symptoms, and Treatment

Understanding Myasthenia Gravis and Dysphagia

Myasthenia gravis is an autoimmune neuromuscular disease that leads to debilitating muscle weakness. It occurs when the immune system produces antibodies that block or destroy nicotinic acetylcholine receptors at the neuromuscular junction. This prevents the neurotransmitter acetylcholine from stimulating the muscles, resulting in weakness and rapid fatigue of any muscles under voluntary control.

One of the most serious symptoms associated with myasthenia gravis is dysphagia or difficulty swallowing. Up to 60% of people with myasthenia gravis experience some form of dysphagia. Understanding the link between myasthenia gravis and swallowing problems is key to managing this bothersome symptom.

How Myasthenia Gravis Causes Dysphagia

The swallowing mechanism requires the coordinated effort of numerous nerves, muscles, and brain pathways. To swallow safely and efficiently, the mouth, pharynx, larynx, and esophagus must work together to move food from the mouth into the stomach while keeping the airway protected.

In myasthenia gravis, the muscles involved in chewing and swallowing can tire quickly with repeated use, making it difficult to move food and liquid through the mouth and throat. The cricopharyngeal muscle which connects the pharynx to the esophagus is commonly affected, making it harder to initiate swallowing.

Muscle weakness in the pharynx and larynx also increases the risk of aspiration, where food or saliva enters the airway. This can occur before, during or after swallowing in people with myasthenia gravis.

Additionally, myasthenia gravis can impact the muscles needed for an effective cough, so any food or liquid that enters the airway is harder to expel.

Common Symptoms of Dysphagia in Myasthenia Gravis

People with myasthenia gravis may experience the following swallowing difficulties:

• Problems chewing food thoroughly
• Food sticking in the throat or going down slowly
• Choking or coughing when eating and drinking
• Drooling due to weak lip closure
• Regurgitation of undigested food
• A gurgly, wet voice after swallowing
• Frequent throat clearing during or after meals
• Aspiration pneumonia due to food/liquid entering lungs

Dysphagia can also cause unintended weight loss and malnutrition as swallowing difficulties make it harder to maintain adequate nutrition and hydration. Dehydration is another serious complication.

Triggers for Dysphagia in Myasthenia Gravis

Anything that exacerbates overall muscle weakness can also worsen swallowing difficulties in myasthenia gravis. Triggers and contributing factors include:

• Eating large, hurried meals
• Talking while chewing or swallowing
• Insufficient chewing due to jaw muscle fatigue
• Consumption of dry, dense, or stringy foods
• Medications like antibiotics that can worsen myasthenia gravis
• Stress, infections, overexertion that increase weakness
• Respiratory infections that impair breathing and coughing

Swallowing trouble is often most severe when myasthenia gravis symptoms are at their peak, such as during an exacerbation or myasthenic crisis. It may improve temporarily after receiving treatments like plasmapheresis or IVIG.

Diagnosing Swallowing Difficulties

A speech-language pathologist can evaluate and diagnose dysphagia through:

• Swallowing assessment - This involves observing the oral and pharyngeal phases of swallowing using foods/liquids with various textures.
• Fiberoptic endoscopic evaluation of swallowing (FEES) - A small scope is passed through the nose to view swallowing in real-time.
• Videofluoroscopic swallow study - Swallowing is recorded on video as patients consume barium-coated foods and liquids.
• Manometry - Measures muscle contractions and coordination when swallowing.

These tests identify which muscles are weakened, whether any food/liquid enters the airway, and how well someone can clear their throat and cough.

Dysphagia Management for Myasthenia Gravis

Treatment focuses on ensuring safe, adequate nutrition and hydration while promoting safer swallowing function. Strategies include:

• Diet modifications - Avoiding hard, dry, or stringy foods that are more difficult to chew and swallow. Eating soft, moist foods requiring less chewing.
• Postural adjustments - Tucking the chin down or turning the head when swallowing to protect the airway.
• Swallowing maneuvers - Techniques like the supraglottic or super-supraglottic swallow to close the larynx entrance when swallowing.
• Medications to improve swallowing ability - Cholinesterase inhibitors or other immune treatments to improve muscle function.
• Tube feeding - Temporary nasogastric or gastrostomy tubes for nutrition/hydration if swallowing is unsafe.

People with myasthenia gravis may also benefit from increased rest before meals, eating smaller or more frequent meals, chewing thoroughly, and remaining upright for 30 minutes after eating.

Preventing Aspiration Pneumonia

Aspiration pneumonia is a serious risk when dysphagia is present. Preventive measures include:

• Seeking treatment at the first sign of swallowing problems.
• Practicing oral care to keep mouth and teeth clean.
• Having regular swallowing assessments to catch issues early.
• Getting recommended immunizations, like the pneumonia vaccine.
• Avoiding smoking, excessive alcohol, and sedatives that impair swallowing.
• Treating reflux disease that can increase aspiration risk.

At the first sign of aspiration pneumonia, such as fever, breathlessness, or coughing up foul-smelling sputum, urgent medical care is needed.

When to Seek Help

People with myasthenia gravis should seek prompt medical evaluation for dysphagia to prevent complications like aspiration, malnutrition, and dehydration. Emergency care is required if choking, significant coughing/gagging when swallowing, or difficulty breathing occurs. Sudden worsening of swallowing difficulties alongside increased muscle weakness may signal a myasthenia gravis crisis.

A multidisciplinary team including neurologists, speech-language pathologists, nutritionists, and physical medicine specialists can help manage dysphagia in myasthenia gravis. Supportive treatments combined with lifestyle changes and swallowing exercises/techniques can help prevent choking episodes and aspiration while ensuring safe, adequate nutrition.

Key Takeaways

In summary, key points about dysphagia in myasthenia gravis include:

• Up to 60% of people with MG experience some degree of swallowing impairment.
• Fatigue of mouth, throat and esophagus muscles makes chewing and swallowing more difficult.
• Choking, food sticking, weight loss, and aspiration are common symptoms.
• Triggers like large meals, dense foods, infections can exacerbate dysphagia.
• Assessment, diet modifications, swallowing techniques help manage dysphagia.
• Prompt evaluation and preventive care are key to reduce aspiration risk.
• Multidisciplinary support provides optimal dysphagia care in MG.

Disclaimer: This article is for informational purposes only and does not constitute medical advice. Always consult with a healthcare professional before starting any new treatment regimen.