Gastroparesis is a disorder defined by delayed gastric emptying, where food remains in the stomach for an abnormally long time without physical blockage. Chronic constipation is a common lower gastrointestinal (GI) issue characterized by infrequent bowel movements or difficulty passing stool. While these conditions affect different parts of the digestive tract, they frequently appear together in the same patient. This co-occurrence raises the question of whether the stomach problem causes the colonic problem. The clinical relationship between gastroparesis and chronic constipation is complex, pointing to a common underlying malfunction of the body’s digestive control system rather than a simple cause-and-effect.
Defining Gastroparesis
Gastroparesis, sometimes referred to as stomach paralysis, is a motility disorder that affects the stomach’s ability to empty its contents into the small intestine. This delayed movement occurs due to impaired function of the nerves and muscles controlling the stomach. The condition is most often linked to damage to the vagus nerve, which regulates the contractions that propel food forward.
When the vagus nerve is compromised, the stomach muscles cannot perform the rhythmic contractions necessary for efficient digestion. This failure causes food to linger in the upper GI tract, resulting in delayed gastric emptying. Patients commonly experience frequent nausea, vomiting of undigested food, and a feeling of fullness after eating only a small amount, known as early satiety.
Other upper GI symptoms include abdominal bloating, upper abdominal pain, and acid reflux due to pressure buildup. The severity of these symptoms can fluctuate, often worsening after consuming high-fat or high-fiber foods, which are inherently more difficult to digest.
Why Constipation and Gastroparesis Often Co-Occur
Gastroparesis itself does not mechanically cause constipation, as the stomach’s contents are not physically backed up into the colon. Instead, the frequent co-occurrence is explained by a shared systemic problem affecting the entire digestive system. The enteric nervous system manages motility from the esophagus to the rectum, and damage to this system often manifests as dysmotility in multiple locations.
This widespread dysfunction is known as pan-enteric dysmotility. Neurological damage, such as the neuropathy caused by long-standing diabetes, affects the nerves throughout the entire GI tract. In this scenario, delayed stomach emptying (gastroparesis) and slow movement in the colon (slow transit constipation) are separate manifestations of the same underlying condition. Studies confirm that patients with gastroparesis have a significantly higher prevalence of slow transit constipation.
The severity of a patient’s constipation symptoms, which can be severe in about one-third of gastroparesis patients, correlates more strongly with the overall delay in colonic transit than with the actual degree of gastric emptying delay. Addressing the colon’s slowness has been shown to improve stomach-related symptoms like nausea and bloating in patients who have both delayed colonic and gastric transit.
Managing Upper and Lower GI Motility Issues
When a patient is diagnosed with both gastroparesis and chronic constipation, management requires a coordinated approach targeting both the upper and lower GI tracts. Dietary modifications are foundational but present a conflict: the ideal diet for gastroparesis is low in fat and fiber, while a high-fiber diet is typically recommended for constipation.
For gastroparesis, the focus is on consuming small, frequent meals that are low in indigestible fiber and fat to minimize stomach retention. To manage constipation, patients must maintain adequate hydration and may use better-tolerated fiber supplementation, such as soluble fiber. Prokinetic medications, like metoclopramide or erythromycin, may be prescribed to stimulate muscle contractions and promote gastric emptying.
Specific therapies are employed for constipation, with osmotic laxatives, such as polyethylene glycol, generally preferred over stimulant laxatives. Certain medications, like prucalopride, enhance motility throughout the entire GI tract, potentially helping both the stomach and the colon. Patients must also be cautious about existing medications, as common drugs like opioids or some antidepressants can significantly slow GI motility and worsen constipation.
In refractory cases, specialized interventions may be considered.
Specialized Interventions
- Gastric electrical stimulation can be an option for the upper tract.
- Lower tract issues, especially those involving pelvic floor dysfunction, may be treated with biofeedback therapy.
The comprehensive treatment strategy must be highly individualized, balancing the need to accelerate movement in the stomach with the need to relieve the backlog in the colon to improve overall quality of life.