Gastroparesis

Gastroparesis

When the stomach doesn’t empty properly either because of poor motility or a functional blockage, then the pressure inside the stomach will exceed the Lower Oesophageal Sphincter (LOS) pressure causing reflux symptoms. It's like a damn across a river causing upstream pressure. Some patients will not suffer from nausea/vomiting/bloating, but rather primarily symptoms solely of reflux although usually there are some associated clues in patients’ presentation. Research also suggests that in some people there is a failure of the valve at the bottom of the stomach, the pylorus, to relax properly rather than failure of the gastric muscles to contract normally. In this case the stomach can’t empty properly as there is a functional blockage rather than poor muscular contraction.

In either case it’s not uncommon for patients with slow stomach emptying to be initially diagnosed with reflux. It’s imperative that if either gastroparesis or pyloric obstruction is present that it is diagnosed. Failure to do so is likely to lead to treatment plans that don’t address the primary cause of symptoms and consequently fail. In particular anti-reflux surgery may exacerbate symptoms if patients are not adequately investigated and diagnosed.

However, gastroparesis will also cause symptoms that are not reflux related.

What is Gastroparesis?

Gastroparesis is a condition in which the stomach fails to empty normally. It is a rare but increasingly common problem.

After eating, food is partly broken down in the stomach before it is then passed into the small bowel. This is facilitated by regular co-ordinated contractions of the muscles within the stomach wall and relaxation of the valve between it and the first part of the small bowel called the duodenum. This is called the pylorus.

Gastroparesis is usually caused by damage to the nerves that regulate this process. The stomach doesn’t contract normally or sometimes the pylorus fails to open and consequently food will remain in the stomach far longer than usual.

What causes Gastroparesis?

In many people a primary cause is never identified. However there are some specific conditions known to be associated with the condition

• Viruses. Some patients will present with a sudden onset of symptoms in isolation or problems associated with delayed gastric emptying will linger after other virus symptoms have resolved. Several specific viruses including Epstein-Barr, Cytomegalovirus, Norovirus and Herpes have all been implicated.
• Diabetes. Longstanding diabetes can cause damage to the nerves affecting the gut generally and the stomach specifically. As diabetes has become more common associated gastroparesis has also become a more frequent problem.
• Surgery. Injury to the Vagus nerves which supply the stomach will cause delayed emptying. Today this probably occurs most frequently following anti-reflux surgery.
• Hiatus Hernias. It is possible that large hiatus hernias which can result in repeated trauma to the Vagus nerves at the hiatus as the stomach passes up and down between the abdomen and the chest may cause delayed gastric emptying.
• Medications. Drugs including opioids and some antidepressants.
• Amyloidosis. This is a rare condition in which deposits of abnormal proteins infiltrate tissues and organs.
• Scleroderma. A connective tissue disease.
• Nervous system diseases. Including Parkinson's disease and Multiple Sclerosis.
• Hypothyroidism. Under-active thyroid.

What are the Symptoms?

Many people will have slow gastric emptying but experience no symptoms. When they do occur they can vary enormously from slightly troubling to potentially life threatening. These can include the following;

• Heartburn and reflux symptoms (see below).
• Nausea.
• Vomiting.
• Early satiety. A feeling of fullness after eating a small meal.
• Vomiting undigested food.
• Upper abdominal bloating.
• Abdominal pain.
• Difficulty controlling blood sugar levels.
• Loss of appetite.
• Weight loss and malnutrition.

Investigations and Tests

• Upper GI Endoscopy. Usually undertaken to exclude other diagnoses including mechanical obstruction and peptic ulcer disease.
• Imaging. Sometimes scans such as CT will be used to exclude intra-abdominal disease.
• Gastric emptying studies. These assess how quickly a substance passes from the stomach into the small bowel either directly using radio-isotopes (usually technetium-99m) or indirectly using breath tests. It can help diagnose gastroparesis or a blockage.
• Electrogastrogram. Delayed emptying can have many causes and measuring the electrical activity in the stomach can help distinguish them from each other. This can be done using electrodes placed on the skin and is painless and non-invasive.
• SmartPill. A small capsule containing an electronic device is swallowed and as it moves through the stomach and gut it sends information to a recorder. This data reflects how quickly food is traveling through the digestive tract and how the digestive tract is functioning.

Treatment

If gastroparesis is diagnosed, then treatment of an identifiable cause is important. So, for instance improved treatment of an under-active thyroid or diabetes may help. If a virus is suspected symptoms tend to settle over time but supportive treatment may be necessary. Options include;

• Dietary changes. A diet low in fibre is likely to promote faster gastric emptying. Eating smaller meals more frequently may also be beneficial.
• Medications. Several drugs can stimulate the stomach to empty better including Metoclopramide, Domperidone and Erythromycin.
• Tube feeding. Reserved for severe cases and either inserted through the nose or using surgery directly into the small bowel.
• Gastric pacemaker. A small electrical stimulator can be inserted to promote stomach emptying.

In the rare cases that a failure of the pylorus to relax and functional obstruction is identified then procedures to disrupt the pyloric valve may help. These include;

• Endoscopic Balloon dilatation. A small balloon is inserted through the pylorus using a standard endoscope and then inflated.
• Per Oral Pyloromyotomy (POP). An instrument is inserted through the pylorus using a standard endoscope and this then used to cut the pylorus. This is occasionally used in severe case of gastroparesis.

Page reviewed by: Mr Nick Boyle BM MS FRCS 01/09/24