Muscle weakness experienced by people with spinal muscular atrophy (SMA) can affect the ability to breathe and swallow. Difficulty with swallowing is called dysphagia, and it can make it hard to take in enough calories and fluids to stay hydrated and nourished. Dysphagia can also put someone at greater risk of aspiration pneumonia. However, there are treatment options that can assist with swallowing and ensure nutritional needs are met.

How Does Spinal Muscular Atrophy Affect Swallowing?

Spinal muscular atrophy is a genetic neuromuscular disease that results in muscle weakness and atrophy. SMA affects the cranial nerves, damaging the motor neurons that control speaking, walking, breathing, and swallowing.

While there currently is no cure for SMA, there are two disease-modifying therapies approved to treat it. However, treating SMA also involves managing symptoms, preventing complications, providing therapy, and maximizing comfort and support for both the person with SMA and any caregivers. All of these are goals in treating swallowing difficulty.

Spinal Muscular Atrophy Types

There are five main types of SMA. The different types of SMA vary in age-at-onset, severity, and degree of disability. SMA types 0, 1, and 2 tend to be more severe than types 3 and 4. Types 0, 1, and 2 are also most likely to include risk factors for respiratory and swallowing problems.

• SMA type 0 is the least common and most severe form of SMA. It begins before birth and affects babies in utero.
• SMA type 1 is typically diagnosed in the first 6 months of an infant’s life. Type 1 is also known as Werdnig-Hoffmann disease.
• SMA type 2 is often diagnosed after 6 months of age but before 3 years of age.
• SMA type 3 usually develops between the ages of 18 months and 30 years. It is also called Kugelberg-Welander disease or juvenile-onset SMA.
• SMA type 4 is also called mild or late-onset SMA. It usually develops in adulthood, after age 35.

What Is Dysphagia?

Difficulty or discomfort when swallowing liquids, foods, or saliva is known as dysphagia. It can sometimes make it difficult to take in enough calories and fluids. Dysphagia also brings a risk of inhaling food or drink (aspiration), which can cause chest infections such as aspiration pneumonia.

What Causes Dysphagia?

Problems sucking and swallowing for people with SMA are usually caused by muscle weakness in the throat and mouth. SMA also causes damage to bulbar motor neurons, which impacts chewing, speech, and swallowing and leads to fasciculations (quivering) of the tongue.

Muscle weakness is most severe in type 0 and type 1 SMA. Older babies and toddlers with SMA type 2 may struggle with chewing in addition to sucking and swallowing. Tongue fasciculations are also common in severe types of SMA.

Diagnosing Dysphagia in SMA

Severe muscle weakness is the most common symptom of SMA. Muscle weakness can impact the ability to breathe and swallow. The most important health assessment for an infant with SMA is how well they can swallow. After an SMA diagnosis, a child should have a video fluoroscopic swallow study or a modified barium swallow. These tests are real-time X-rays that take images of the full swallowing process. This allows doctors to determine what interventions are needed to make eating less risky or more effective.

How Do Swallowing Difficulties Affect People With SMA?

Poor ability to suck and swallow can lead to malnutrition and dehydration. Dysphagia may also result in aspiration, which happens when foreign matter — such as food or liquid — gets into the airway and lungs.

Aspiration

Aspiration occurs when food, saliva, liquids, or vomit is breathed into the airways leading to the lungs, instead of moving through the esophagus to the stomach. Breathing food particles into the lungs can cause infection. When pneumonia is caused by inhaling bits of liquids or food, it is called aspiration pneumonia.

Nutritional Deficiencies

Proper nutrition is vital to healthy growth and overall well-being. Dysphagia can make ensuring adequate nutrition especially complex for people with SMA. The main nutrition-related problems associated with SMA are:

• Dehydration
• Malnutrition
• Weight management
• Proper digestion

Managing SMA-Related Dysphagia

Speech-language pathologists are often engaged to help treat swallowing and feeding problems. Speech-language pathologists are trained in the anatomy of the mouth, throat, and voice box or larynx. Sometimes called speech therapists, these professionals are often best suited to evaluate and treat swallowing problems.

Together with other health care providers, such as nutritionists, speech-language pathologists can help people with SMA overcome swallowing muscle weakness. They can advise on head posture adjustments and how to prepare food for safer swallowing, use feeding tubes, and manage other issues related to dysphagia in SMA.

Supportive Feeding Methods

Adequate nutrition in the early stages of life is vital for proper development, growth, and weight gain. Infants and children with SMA who have severe swallowing and sucking issues may require supportive feeding methods, as well as regular nutritional evaluations from their health care provider.

Some people with SMA who have difficulty swallowing may benefit from a feeding tube. A feeding tube is a small, flexible tube that helps ensure a person gets adequate nutrients. A feeding tube bypasses the mouth, throat, and esophagus and connects directly to the gastrointestinal tract. Some feeding tubes can be detached from the abdomen when not in use. There are a variety of supportive feeding tubes:

• In nasogastric (NG) intubation, a feeding tube is placed through the nose, past the throat, and down into the stomach.
• During nasojejunal (NJ) intubation, a feeding tube is placed through the nose, past the throat and stomach, and down into the small intestine.
• A gastrostomy tube or PEG endoscopy is surgically placed into the stomach through the skin.

SMA can cause stiffening of the jaw muscles. This can make chewing solid food difficult or tiring. Jaw stiffness may also contribute to swallowing problems and nutrition deficiencies. People with SMA sometimes use a combination of oral and nonoral feeding methods, eating by mouth for pleasure and using supportive methods to ensure adequate hydration and nutrition.

Learn more about nutritional treatments for SMA.

If you or your child is experiencing difficulty with swallowing, stiff jaw muscles, or maintaining a healthy weight, it is very important to talk to your doctor about these symptoms. Your health care team can support you in ensuring adequate nutrition and avoiding infection.

Have you or a loved one experienced difficulty with swallowing? Have you found any therapies that helped? Comment below or start a conversation on mySMAteam. You never know who might benefit from hearing your story.