Respiration or breathing is primarily under the control of the autonomic or “automatic” nervous system—the part of the central nervous system that controls vital functions such as heartbeat and respiration without conscious thought. It is unusual for MS to affect the autonomic nervous system, and therefore uncommon for breathing problems to occur in MS as a direct result of loss of autonomic control. If breathing problems occur suddenly, it is imperative to see the health care provider immediately or go to the emergency room since this may indicate infection or some other problem.
Weakness of the ventilatory muscles can begin early in the disease
In MS, the most common cause of respiratory problems is loss of muscle strength and endurance. Just as a person can experience muscle weakness in the arms or legs, weakness can occur in the ventilatory muscles of the chest and abdomen that are involved in breathing. And like weakness in the other parts of the body, weakness of the ventilatory muscles can begin to occur early in the disease course and gradually worsen over time.
Aspiration of food particles into the lungs can also affect respiration
Breathing problems can also occur as a result of aspiration pneumonia. Aspiration pneumonia results from the inability to clear secretions from the nose and throat, or from swallowing difficulties that result in inhalation of food particles into the lungs. Evaluation and treatment by a speech/language pathologist is essential for anyone who begins to experience swallowing difficulties and/or choking while eating or drinking. In addition to exercises and other forms of therapy to improve a person’s swallow, the therapist may also recommend dietary changes and postural changes while eating to minimize swallowing problems. Sometimes, a feeding tube is necessary to avoid continued risk of aspiration pneumonia.
Certain medications may also contribute to respiratory problems
Some medications, such as tranquilizers, muscle relaxants, and opioid analgesics, can depress breathing. The use of these medications should be carefully monitored in anyone with a history of respiratory distress or swallowing problems.
Respiratory changes can contribute to other problems
People with weakened ventilatory muscles have to work harder to inhale and exhale. This extra effort can be quite tiring, particularly for people who already experience a significant amount of MS fatigue. Respiratory problems can also interfere with the process of speech and voice production—making it much more difficult and tiring for people to carry on a conversation or speak loudly enough to be heard. The speech/language pathologist can recommend exercises and tools to enhance speech and communication.
A baseline evaluation of respiratory function is useful
Because weakness of the ventilatory muscles can occur at any time, many MS specialists recommend a baseline evaluation at the time of diagnosis, followed by periodic evaluations (every 1-3 years) thereafter. These evaluations are most often done by a physical therapist or nurse with special training in this area. In the event that respiratory function becomes affected, a therapy program can be recommended to strengthen ventilatory muscles and enhance respiration.