Host:

The small intestine is where food is digested and the main site of absorption. When there are congenital factors or a partial resection, intestinal function can be affected.Individuals may need to live on nutrient solution via a tube. This rare disease is called short bowel syndrome.

Today, we've invited Dr Rosanna Wong, Chief of Service, Department of Paediatrics and Adolescent Medicine at Hong Kong Children's Hospital to tell us about this condition.

Hello, Dr Wong, can you tell us about it? What is the normal length of the small intestine? What is the length of a person with short bowel syndrome?

Dr Rosanna Wong:

Generally, the length of a normal small intestine for a full-term baby is about 250 to 300 cm. If the baby is born premature, the length may be shorter, around 150 cm. In case of short bowel syndrome, due to various reasons requiring intestinal resection, the remaining small intestine maybe as short as 100 cm, or even 80 cm or less. For short bowel syndrome, the length is not the most important factor. The most important aspect is its function - whether it can maintain food absorption to sustain life, and absorb the necessary nutrition.

Host:

Let's talk about the function of the small intestine. What problems will occur if it is not long enough?

Dr Rosanna Wong:

The main function of the small intestine is to absorb nutrients and water. If the length is insufficient, there won't be enough time to absorb these essentials, leading to nutrient deficiencies. The first symptom is diarrhea and individuals may feel discomfort in their stomachs. Additionally, growth cannot be achieved and maintaining weight becomes difficult. Besides weight, other nutrients like vitamins, are also needed. In the case of a short intestine, malnutrition can occur. Some children may experience more severe symptoms.

Host:

Is it related to the remaining length of the small intestine?

Dr Rosanna Wong:

That's correct. Severity is related to the length of the remaining small intestine. Generally, if a newborn baby has a remaining length of under 40 cm, the symptoms are more serious.

Host:

Have you encountered some of these children, doctor? How short was the shortest ones?

Dr Rosanna Wong:

Among the children I have treated, the shortest small intestine may be less than ten centimeters. They all require long-term intravenous nutrition support.

Host:

I understand that adults have longer small intestines than children. Does it mean that as children grow, their small intestines also grow? Will their symptoms gradually improve?

Dr Rosanna Wong:

It depends on how much intestine is left. If a significant portion of the normal intestine is removed, the remaining intestines have the ability to adapt and can grow. The intestinal membrane will become thicker and the villi will grow denser. This adaptation allows the shorter intestine to absorb more nutrients, which can alleviate symptoms to some extent. If the intestine is not too short and is well cared for, the absorption capacity can gradually improve and the individual may no longer require intravenous nutrition. However, if it is too short, less than 40 cm or even 20 cm, long term treatment with intravenous nutrition is usually necessary.

Host:

Some patients with this disease are born with it, while others have had their intestines removed later in life. Why might someone need to have their small intestine removed?

Dr Rosanna Wong:

One of the most common reasons is premature birth. Premature infants may experience infections that lead to necrosis of the small intestine, a condition known as necrotizing enterocolitis. If the situation is severe, a significant portion of the intestines may need to be removed, resulting in short bowel syndrome.

Host:

Some children with short bowel syndrome require long-term intravenous feeding. What impact does this have on their quality of life?

Dr Rosanna Wong:

Intravenous nutrition for children with short intestines is life-sustaining. However, long term intravenous nutrition can damage the liver. For some individuals on it for years, liver failure may occur. Additionally, intravenous nutrition requires the use of an intravenous catheter, which, if not handled properly, may lead to the risk of infection.

Host:

For children receiving long-term intravenous infusion, does this mean they cannot eat normal food?

Dr Rosanna Wong:

Not necessarily. Even with short bowel syndrome, we encourage children to eat. Because food is essential to their quality of life. We advise caregivers to choose nutritious food that are easily digestible. For infants, breastfeeding is particularly beneficial, as breast milk is easy to absorb. Special hydrolyzed milk formulas can also help. As children grow, they can try a variety of foods, but this should be supervised to avoid malabsorption and severe diarrhea.

Host:

Intravenous nutrition is one of the main treatment methods now, but are there any risks? Will there be any new breakthroughs in medical treatment?

Dr Rosanna Wong:

Yes, intravenous nutrition itself has improved, and we now use better catheters to lower the risk of infection. There are also new drugs that provide hope for children with short bowel syndrome. One of such drugs is Glucagon-like Peptide-2 (GLP-2), an endocrine hormone that can be injected subcutaneously. While it is not yet registered in Hong Kong, medical evidence suggests it can stimulate the growth of the remaining intestine, leading to a thicker mucosal wall, increased villi and improved blood flow. This may enhance intestinal absorption capacity and reduce or eliminate the need for intravenous nutrition.

Host:

Thank you, Doctor, for sharing with us today. Let's wrap it up here. Goodbye.