Gut GVHD: diarrhoea, grading and the warning signs | CION Cancer Clinics

Gut GVHD typically causes large amounts of watery loose motions, often with cramps, after a donor stem cell transplant. It becomes serious when the volume is high, when there is blood, or when you cannot keep up with the fluid you are losing. The grade depends mainly on how much stool you pass each day.

What is happening inside the gut

The donor immune cells attack the lining of the bowel. That lining normally absorbs water and food. When it is damaged, water pours through instead, and the stool becomes watery and frequent. In severe cases the lining bleeds.

The upper gut is affected too

Sometimes GVHD affects the stomach and upper bowel instead of, or as well as, the lower bowel. The signs are different: feeling sick, vomiting, loss of appetite and feeling full after a few mouthfuls. This form is often milder and responds well to treatment, but it still needs a proper assessment.

Why not every loose motion is GVHD

Infections are a very common cause of diarrhoea after transplant, and so are some medicines. An infection treated with extra immune-quietening medicine can get much worse. That is why the team tests for infection before or alongside treating GVHD. Some antibiotics, magnesium supplements and the liquid feeds used after transplant can also loosen the stool. Bring every medicine and supplement you are taking to the appointment, including anything bought without a prescription, so the team can check each one as a possible cause.

Fluids come first. Sip oral rehydration solution through the day, rather than plain water alone, unless the team has told you otherwise. If you are passing large amounts, you may need fluids through a drip, and that is a reason to be in hospital.

Resting the gut, then building back

In severe gut GVHD, the team may ask you to stop eating for a short time and give nutrition through a vein. As things settle, food is brought back in stages. Soft, bland foods such as rice kanji, idli, curd rice and banana usually come first. Milk, fried food, spicy food and raw salads are usually held back until the gut recovers.

Who this advice does not suit

People with diabetes, kidney problems or heart failure may need a different fluid and salt plan. A dietitian at the transplant centre can set one. Do not start supplements or herbal remedies, because some interact with transplant medicines.