Gastroparesis

How the stomach empties

After you eat, the upper stomach relaxes to hold food, then muscular contractions grind it into tiny particles and push it through the pylorus (the stomach outlet) into the small intestine. The vagus nerve and specialized pacemaker cells coordinate this. In gastroparesis, nerve or muscle damage disrupts the process, and food sits in the stomach for too long.

Symptoms

• nausea, often the most troublesome symptom
• vomiting, sometimes of food eaten hours earlier
• early satiety: feeling full after a few bites
• fullness lasting long after meals
• bloating and upper abdominal discomfort or pain
• heartburn or reflux
• poor appetite and weight loss
• in diabetes: unpredictable blood sugar, with lows soon after insulin and highs later as food finally empties

Symptoms overlap substantially with functional dyspepsia, and some experts consider them related conditions.

Causes

Diagnosis

1. Rule out a blockage: upper endoscopy to exclude an ulcer, tumor or narrowing at the stomach outlet (gastric outlet obstruction). Food remaining in the stomach after an overnight fast is a clue.
2. Measure stomach emptying: - gastric emptying scintigraphy: you eat a standard low-fat egg meal with a tiny amount of radioactive tracer, and scans over 4 hours measure how much remains. More than 10% left at 4 hours indicates delayed emptying - gastric emptying breath test: measures a marker in breath samples after a test meal - wireless motility capsule in some centers
3. Stop medicines that slow emptying before testing where possible, and check blood sugar on the test day, as high glucose itself slows emptying.
4. Blood tests: blood sugar, HbA1c, thyroid function, and electrolytes.

The gastroparesis diet

Diet changes are the foundation of treatment:

• eat 4 to 6 small meals a day instead of 3 large ones
• choose small-particle foods: foods that are soft, pureed or easy to mash with a fork empty more easily. A study of a small-particle diet showed symptom improvement in diabetic gastroparesis
• limit fat in solid foods, as fat slows emptying. Fat in liquids (such as smoothies) is often tolerated
• limit insoluble fiber: raw vegetables, skins, seeds, nuts, corn and fibrous fruits, which can form clumps (bezoars)
• chew well and eat slowly
• sit upright or walk for 1 to 2 hours after eating
• use liquid nutrition (soups, smoothies, nutritional shakes) when solids are poorly tolerated
• avoid alcohol and smoking

A dietitian can help ensure adequate calories, protein and vitamins.

Medical treatment

• Blood sugar control: improving glucose levels can improve emptying; continuous glucose monitors and insulin timing adjustments help.
• Stop or reduce medicines that slow the stomach, where safe.
• Metoclopramide: the only FDA-approved medicine for gastroparesis. It improves emptying and reduces nausea. Because of the risk of tardive dyskinesia, use is generally limited to 12 weeks, with monitoring.
• Domperidone: available in many countries but in the US only through a special FDA program.
• Erythromycin: an antibiotic that stimulates stomach contractions, used short-term.
• Antiemetics: ondansetron, prochlorperazine and others for nausea.
• Neuromodulators for pain and nausea in some cases.

Procedures for severe cases

• Gastric per-oral endoscopic myotomy (G-POEM): cuts the pyloric muscle from inside to help the stomach empty
• Gastric electrical stimulation: an implanted device to reduce nausea and vomiting, used mainly in diabetic gastroparesis
• Feeding tubes: a jejunostomy tube delivers nutrition directly into the small intestine for people who cannot maintain weight
• Venting gastrostomy to relieve pressure

Complications

• dehydration and electrolyte imbalance
• malnutrition and weight loss
• bezoars: hardened masses of undigested food
• unstable blood sugar in diabetes
• reduced quality of life

Frequently asked questions

What are the symptoms of gastroparesis?

Common symptoms are nausea, vomiting (sometimes of undigested food), feeling full after a few bites, prolonged fullness after meals, bloating and upper belly pain. People with diabetes may have unpredictable blood sugar levels.

What causes gastroparesis?

The most common causes are diabetes, unknown (idiopathic) causes, damage to the vagus nerve during surgery, and medicines such as opioids and GLP-1 agonists. Neurological diseases, scleroderma and hypothyroidism are other causes.

What foods should you avoid with gastroparesis?

Limit high-fat solid foods, high-fiber foods such as raw vegetables, skins, seeds, nuts and corn, carbonated drinks and alcohol. Small, frequent meals of soft or pureed foods are usually best tolerated.

Can gastroparesis be cured?

Gastroparesis caused by medicines may resolve when the drug is stopped, and some post-viral cases improve over time. Diabetic and idiopathic gastroparesis are usually long-term but can be managed with diet, medicines and procedures.