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Treatment options for patients with abdomino-phrenic dyssynergia (APD)
Abdominal distension occurs when the abdominal or belly area visibly expands. In most patients, distension develops during daily activity and tends to lessen or disappear after a night’s rest. Many people with gastrointestinal (GI) illnesses experience visible abdominal distension.
Is It Bloating or Distension?
Bloating is described as the feeling of swelling or a build up of pressure in the abdomen. Sometimes it can be described as the feeling of an inflated balloon in your stomach or intestines. Distension, however, is the visible increase in the width of your abdominal girth, or the area between your hips and chest. Feeling bloated is not always accompanied by the physical symptom of distension.
What is considered “normal”?
Over the course of a day, contents inside of the abdomen naturally changes. The abdomen includes digestive organs like the stomach and intestines, and it’s and its contents increase and decrease as we eat, drink, urinate, and have bowel movements (BM’s). For that purpose, the abdominal wall actively changes to fit what is inside. This is done by tight control of the muscles that make up the walls.
In healthy people, when the amount of material inside the abdomen increases, the diaphragm relaxes. The diaphragm is the muscle that separates the chest from the abdomen and helps with breathing. When it relaxes, it allows the stomach and other digestive organs to move slightly upward into the chest.
This creates extra space for the digestive tract to hold more contents without having to expand outward, helping the abdomen stay comfortable and flexible throughout the day.
Causes of Abdominal Distension
Abdominal distension (when the belly feels swollen or pushed outward) has been studied by looking at the same person when their abdomen feels “normal” and when it feels distended. Researchers used two main ways to study this. They measured what was inside the abdomen, including food, fluid, and gas in the intestines and looked at how the abdominal muscles move and work.
This was done using:
- CT scans, which take detailed x-ray pictures of the inside of the body, including the abdominal wall and the diaphragm (the muscle that helps with breathing).
- EMG tests, which measure how active the abdominal muscles are by recording the electrical signals they produce when they tighten or relax.
From these studies, researchers found:
- People with abdominal distension do have a real, measurable increase in belly size during episodes.
- Although many people think bloating is caused by too much gas, extra gas is usually not the main cause. An exception may be people with certain conditions, such as small intestinal bacterial overgrowth (SIBO), where excess bacteria can increase gas.
In most people, abdominal distension happens because of abnormal muscle movement. The diaphragm tightens in a way that pushes the abdominal contents downward, causing the belly to push outward. This unusual muscle movement can also contribute to why some people feel short of breath when their abdomen is distended.
What triggers abdominal distension?
People typically describe that distension begins quickly once it is triggered. In the studies described previously, distension occurred in less than 60 seconds in 35% of people, and less than 10 min in another in 26%. Events that can trigger distension may include certain foods and stressors. These potential causes are discussed below.
Eating Meals
Some people who experience abdominal distension have a more sensitive gut. This means that even small changes in the intestines can trigger a strong sensation of bloating. In people who regularly respond like this, a small sensation may trigger the abnormal response that produces abdominal distension. In fact, bloating and distension may be related to food intake. A large number of people with bloating, describe that it develops or worsens shortly after meals. Some people express that they are unable to complete a full meal because of bloating. This effect is more obvious when eating large and especially fatty meals. Bloating after meals is a typical trait in specific groups of people. This can include those with dyspepsia and people who binge eat. High fiber foods or fiber supplements are also believed to worsen bloating. Fiber increases the volume of intestinal content, leading to a feeling of bloating.
Food Intolerances
Specific food intolerances have also been connected with bloating and distension. One example is dairy products, however it has been shown that only a fraction of these cases are truly due to lactose intolerance. This intolerance occurs when the lactase enzyme is not present in the GI tract, preventing dairy from being broken down properly by the body. If symptoms occur with a low amount of dairy, it is unlikely to be caused by an intolerance. Fatty foods and carbonated drinks are other examples and are frequently reported as a cause. Some people say that eating lettuce and other green leafy vegetables cause them gas and abdominal distension.
Constipation
Some people with bloating and abdominal distension have constipation due to anal dyssynergia. This condition occurs when muscles of the anus do not contract together properly. The anus is the lower opening of the GI tract. Normal bowel movements occur when the abdominal wall is pushing and is then followed by a relaxation and opening of the anal canal. It has been shown that correction of anal dyssynergia can relieve distension and bloating. This can be done through biofeedback, the use of electrical stimulation to help train muscles.
Treating Underlying Constipation
If present, constipation should be treated to help with symptoms. Some common treatments for constipation are also known for causing bloating. It is best to always ask your healthcare provider before starting treatment. Treating constipation also varies depending on severity. Some known treatments for constipation are listed below:
- Bowel retraining
- Increased hydration and exercise
- Biofeedback
- Laxatives
- Medications
Prokinetics and Spasmolytics
How each person experiences symptoms, particularly bloating, is a key factor often associated with distension. As a result, treatment with prokinetics or spasmolytics may relieve abdominal symptoms. Prokinetics are drugs that increase the frequency of contractions in the GI tract. This may improve movement of contents through the GI tract and stomach emptying. Spasmolytics are drugs that help reduce smooth muscle spasms. Smooth muscles make up the lining of the GI tract and other organs.
Biofeedback
As mentioned previously, biofeedback is the use of electrical stimulation to help train muscles. Biofeedback has been proven useful to correct muscle tone and resolve distension. The use of this treatment, however, is limited as it can be complex and costly. A new standardized biofeedback technique has been developed in Spain. Unfortunately, it is not widely available but can be found in some specialized medical centers
Diagnosing Abdomino-Phrenic Dyssynergia (APD)
Testing for Abdomino-Phrenic Dyssynergia (APD) or visible abdominal distension is typically not required given the previously discussed symptoms and data. If needed, a CT scan and electromyography (EMG) can be done. Due to the abnormal movement of the diaphragm, which can be associated with APD, an ultrasound can be done to help identify these movements. An ultrasound is a noninvasive test that uses sound waves to produce images of inside the body.
Managing APD
Unfortunately, there are no standardized treatments for APD presently, however there are multiple
management strategies that can be explored with your healthcare provider.
Lifestyle and Dietary Modifications
The initial line of treatment in patients with abdominal distension would be to target triggers, such as increased content in the intestines. Specifically, it is wise to avoid diets rich in fermentable foods, such as yogurt, kimchi, and kefir, as well as fiber supplements.
Adapted from IFFGD’s Publication #286: Abdomino-Phrenic Dyssynergia (APD) or Visible Abdominal Distension by Elizabeth Barba, M.D., Digestive System Research Unit, University Hospital Vall d’Hebron; Department of Medicine, Barcelona, Spain and Fernando Azpiroz, M.D., Digestive System Research Unit, Hospital General Vall d’Hebron, Barcelona, Spain