Patient Information: Childhood Illnesses

What You Should Know About

Respiratory Effects of Neuromuscular Disease

Neuromuscular disease is a general term that covers more than 40 diseases. The best known example is probably muscular dystrophy. Because breathing depends largely on the smooth functioning of the muscles and bones surrounding the lungs, neuromuscular diseases can profoundly threaten the affected person's ability to breathe.

Symptoms of weakened respiratory muscles

As a neuromuscular disease progresses, the affected person will become less able to move adequate amounts of air in and out of the lungs. Early in this process, the resulting symptoms can easily be mistaken for other problems. That's because shortness of breath - the hallmark symptom of inadequate oxygen - may not appear, particularly if the person is too weak to exercise vigorously.

Instead, the early symptoms of poor ventilation may include fatigue, disturbed sleep, and headaches, especially just after waking. In fact, poor ventilation at night is often the first problem, both because the natural urge to breathe is lower during sleep and because the abdominal organs push upward against the diaphragm - the major breathing muscle - when a person lies down.

Other results of poor ventilation may include anxiety, confusion, loss of appetite, and weight loss. Plus, the person may have a weak voice and an ineffective cough that isn't strong enough to move mucus up toward the mouth. All these changes suggest that the respiratory muscles are losing their power.

Treatment and tips

A specialist in pulmonology will most likely direct the respiratory care of anyone who has a neuromuscular disease. In fact, this doctor will probably devise a special plan of care based on the specific functional ability and needs of the affected person as identified by several important tests.

Pulmonary function tests

During pulmonary function tests, the patient breathes through a mouthpiece into a machine that analyzes the lungs' ability to function normally. A clip holds the patient's nose closed during the test. As the patient performs this test repeatedly over time, lung function is plotted and followed. If the test measure a significant decline in function, the doctor will begin thinking about ways to help the patient move air in and out of the lungs. Usually, this test isn't performed on children younger than about age 5 because the patient needs to be able to follow verbal instructions.

Blood tests

To get an idea of how well the patient's lungs are functioning, blood may be drawn or a finger pricked to measure the level of oxygen and waste (carbon dioxide) in the blood. Another test, called pulse oximetry, measures the amount of oxygen in the blood using a painless device clipped to the patient's finger or ear.

Maximizing respiration

A person with a neuromuscular disease may benefit from several exercises and treatments aimed at improving breathing. One of the most important is deep breathing and coughing, which the patient can and should do independently. These are the body's natural mechanisms for clearing the lungs of mucus and other matter.

Aerosol therapy

This form of therapy delivers medications directly into the lungs using a nebulizers or a metered-dose inhalers. Specific medications may be prescribed include:

• antibiotics, which combat infection
• bronchodilators, which relax smooth muscles in the airway and may assist with airway clearance
• anti-inflammatories which help to open airways narrowed by inflammation and swelling.

Cough therapy

Certain devices are available to help strengthen the patient's coughing mechanism and clear mucus from the lungs. These are especially important if the patient has a cold or other upper respiratory infection that's producing excess mucus.

One device, called an intrapulmonary percusionater, can simultaneously deliver aerosolized medication and loosen mucus from airway walls. The patient breathes through the tubing and mouthpiece for 15 to 20 minutes three to four times a day until the mucus has cleared.

Another device, called the Emerson In-Exsufflator, is a small electrical machine that can assist a weak cough effort and make it effective in expelling mucus. The device can push a volume of air into the lungs and quickly pull that same volume of air out of the lungs, imitating a strong cough effort. As with any respiratory therapy equipment, the health care team will help you or your child learn to use and operate this device.

Ventilatory assistance

If a neuromuscular disease weakens the person's breathing ability so much that the lungs can't pull in enough oxygen, a machine can be used to assist the breathing process. It's called a ventilator, and it delivers a preset amount of air into the lungs. At first, you'll probably use this machine only at night, when the body's urge to breathe is naturally reduced. Later, the patient may need to use it during the day as well. A mouthpiece can be used in the daytime and a nasal or facemask can be used during sleep. The machine can easily fit on a ventilator tray on the bottom of a power wheelchair.

Where to Get More Information

For more information on neuromuscular disease, try this online resource.

• Muscular Dystrophy Association