Gastroparesis: when the stomach empties too slowly

Gastroparesis: When the Stomach Empties Too Slowly

Gastroparesis literally means "paralysed stomach". The normal muscular contractions of the stomach are disrupted, causing food to remain in the stomach for too long. This leads to early satiety, nausea, and vomiting of food that is sometimes several hours or even days old. The condition is underdiagnosed. Many patients are misdiagnosed with reflux or functional dyspepsia for years before the correct answer emerges.

The condition is not uncommon in people with long-standing diabetes, but it can also occur after a viral infection, certain surgeries, or with no identifiable cause.

What are the symptoms?

Symptoms often fluctuate from week to week, but the classic presentation includes:

• Rapid fullness, often after just a few mouthfuls
• Persistent feeling of fullness for hours after a meal
• Nausea and vomiting, especially late in the day or the next morning
• Vomiting of undigested food from a previous meal
• Bloating and pain high in the abdomen
• Heartburn and reflux due to an overfilled stomach
• Unexplained weight loss and poorly controlled blood sugar in diabetics

Many describe feeling "full" after a glass of water or having to leave half a plate of food untouched. This is not psychological; it is a physical delay in stomach emptying.

Why does it happen?

The stomach empties through a coordinated interaction between the vagus nerve, smooth muscles, and a group of pacemaker cells (Cajal cells). If any of these systems are affected, gastroparesis can occur. The most common causes are:

• Diabetes (type 1 and type 2): High blood sugar over years can damage the vagus nerve. In series from specialist centres a substantial proportion of patients with long-standing type 1 diabetes have some form of delayed gastric emptying. The proportion varies widely between series because the measurement method and the patients studied differ, and it cannot be transferred directly to the individual.
• Idiopathic: Without an identifiable cause, often following a stomach virus or other infection.
• Post-surgical: After operations where the vagus nerve may be damaged, such as fundoplication, bariatric surgery, or oesophageal surgery.
• Medication: GLP-1 analogues (Ozempic, Wegovy, Mounjaro), opioids, anticholinergics, and certain antidepressants can delay emptying.
• Connective tissue diseases: Scleroderma, amyloidosis.
• Neurological diseases: Parkinson's disease, multiple sclerosis.

GLP-1 analogues deserve a special mention. They delay gastric emptying as part of their mechanism of action, and in some individuals, this can cause pronounced gastroparesis-like symptoms. If this happens, the treating doctor decides how to proceed, and symptoms are followed afterwards. Never stop prescribed medicine on your own.

How is it diagnosed?

Diagnosis is based on three pillars:

1. Symptom profile including nausea, fullness, and vomiting that has persisted for more than three months.
2. Exclusion of mechanical obstruction via gastroscopy. The stomach must be open, not narrowed by ulcers, polyps, or tumours.
3. Measurement of gastric emptying, most commonly with a four-hour scintigraphy after a standardised meal. Retention at four hours above the threshold the laboratory uses for that meal points to delayed gastric emptying. The test is a clinician's tool: the diagnosis is made only when the finding fits the symptoms and mechanical obstruction has been excluded, and the result can be affected by blood glucose and by certain medicines.

Blood tests are taken to assess blood sugar, HbA1c, electrolytes, and thyroid function, as untreated hypothyroidism can mimic the condition.

Treatment

Treatment is stepwise and requires patience. There is no miracle cure, but a combination of dietary changes, medication, and blood sugar control can enable many to lead a functional daily life.

Diet:

• Eat five to six small meals instead of three large ones.
• Reduce fatty foods, as fat further slows emptying.
• Reduce insoluble fibres (raw vegetables, whole grains, popcorn), as they can form hard clumps (bezoars).
• Chew slowly and thoroughly.
• Drink calories if solid food is difficult to consume, e.g., soups, smoothies, and nutritional drinks.
• Avoid lying down immediately after meals.

Medication:

• Metoclopramide (Primperan) is a prokinetic. The European Medicines Agency (EMA) has restricted its approved use to short-term treatment of, among other things, nausea and vomiting, for a maximum of 5 days, and has removed chronic conditions including gastroparesis from the approved use because of the risk of neurological side effects such as tardive dyskinesia (EMA on metoclopramide). Long-term treatment of gastroparesis therefore falls outside the approved use and can only be considered as a separate specialist decision, with attention to side effects and monitoring. Drug, dose and duration are decided by the treating doctor. Never stop prescribed medication on your own.
• Domperidone, where available, has fewer neurological side effects.
• Erythromycin in low doses stimulates the stomach via motilin receptors, but its effect diminishes over weeks.
• Antiemetics (ondansetron, prochlorperazine) for nausea.

Blood sugar control is crucial for diabetic gastroparesis. High blood sugar further delays emptying, and poorly distributed meals and insulin doses worsen the problem. An insulin pump and continuous glucose monitoring help many.

Advanced treatments for the few with severe, treatment-resistant disease:

• Pyloric Botox injections during gastroscopy (short-term effect, controversial).
• G-POEM (gastric peroral endoscopic myotomy): endoscopic incision of the pyloric muscle. Promising results.
• Gastric pacemaker (gastric electrical stimulation) for severe diabetic or idiopathic gastroparesis.
• Feeding tube (jejunostomy) if solid food can no longer be tolerated.

When should you see a doctor?

Contact your GP if for more than a few weeks you have experienced:

• Persistent nausea after meals.
• Vomiting of food from previous meals.
• Unexplained weight loss.
• Fluctuating blood sugar if you have diabetes.
• Fullness after small portions combined with bloating.

Contact the regional acute helpline the same day if repeated vomiting means you cannot keep fluids down or you develop signs of dehydration such as dizziness and very little urine. Call 112 for impaired consciousness, collapse or another life-threatening condition.

Frequently Asked Questions

Is gastroparesis chronic? For most, it is long-term, but symptoms fluctuate. Post-viral gastroparesis can resolve over months to years. Diabetic gastroparesis often follows blood sugar control.

Can Ozempic cause permanent gastroparesis? Symptoms resolve for most people after discontinuation, but there are reported cases where they last longer. If you develop pronounced symptoms on GLP-1 medication, discuss it with your doctor.

Do acupuncture or ginger help? Ginger has a mildly documented effect against nausea. Acupuncture has weak evidence. Both are safe to try, but neither can be a standalone treatment.

Should I completely avoid fibre? No. Soluble fibres (oatmeal, cooked carrots, bananas) are often tolerated. It is the tough, insoluble fibres you should be cautious with, as they can form bezoars.

References

1. Camilleri M, Kuo B, Nguyen L, et al. ACG Clinical Guideline: Gastroparesis. Am J Gastroenterol. 2022;117(8):1197-1220. PubMed
2. Schol J, Wauters L, Dickman R, et al. United European Gastroenterology (UEG) and European Society for Neurogastroenterology and Motility (ESNM) consensus on gastroparesis. United European Gastroenterol J. 2021;9(3):287-306. PubMed
3. Sundhed.dk. Gastroparese (lægehåndbogen).
4. Grover M, Farrugia G, Stanghellini V. Gastroparesis: a turning point in understanding and treatment. Gut. 2019;68(12):2238-2250. PubMed

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This article provides general information and does not replace a medical consultation. Contact your GP if you experience symptoms.