Introduction

What is necrotising enterocolitis?

Necrotising enterocolitis (NEC) is a serious condition that affects babies prematurely. It happens when the lining of a baby’s intestine becomes inflamed and starts to break down. In more severe cases, parts of the bowel can become damaged or die, and holes may appear in the bowel wall. This allows bacteria to leak out into the baby’s stomach or bloodstream, which can lead to dangerous infections.¹

NEC usually develops within the first few weeks of a baby’s life. The condition can be mild or, in some cases, life-threatening. Because of this, babies with NEC are treated in a neonatal intensive care unit (NICU), where they receive close and constant monitoring.

Premature babies, especially those who weigh less than 5½ pounds at birth, have the highest risk of developing NEC. However, NEC can also affect full-term babies, particularly those who are already unwell or who have other medical issues.

The role of the intestine

The bowel, also known as the intestine, is an important part of the body’s digestive system. It plays a key role in absorbing nutrients from food and removing waste products from the body. When the intestine is damaged or inflamed, as it is in NEC, these processes can be disrupted. This may lead to poor nutrient absorption, digestive problems, and other serious health issues.

What are the complications of NEC?

While many babies recover well from NEC with the right treatment, some may go on to develop long-term complications. These complications can have an impact on a baby’s health and development and often require further care and medical attention. The three main complications of NEC are short bowel syndrome, intestinal strictures, and sepsis. Each one can affect babies in unusual ways and may appear at various times during recovery.

Short bowel syndrome

What is short bowel syndrome?

Short bowel syndrome (SBS) is a condition that happens when a significant part of a baby’s small intestine has been removed, usually during surgery to take out damaged sections caused by NEC. The small intestine is the part of the digestive system responsible for absorbing most of the nutrients from food. When a large portion is missing, the body may not be able to absorb enough fluids, energy, vitamins, or minerals.²

This can lead to long-term feeding and growth problems, particularly in premature babies who already need extra nutritional support.

Symptoms of SBS

Babies with SBS may show signs such as frequent loose or watery stools, a swollen or bloated tummy, slow or poor weight gain, and dehydration. They may also become tired or weak. In some cases, the lack of proper nutrient absorption can lead to deficiencies in vitamins or minerals, which can affect the baby’s overall health and development.³

Diagnosis and tests

If doctors suspect SBS, they will look at your baby’s medical history and current symptoms. Blood tests can help check for dehydration or low levels of nutrients. A stool test might be done to see how well your baby is absorbing fat and other nutrients. Imaging tests, such as X-rays or CT scans, can be used to view the structure of the intestines and identify any problems.

Treatment

Managing SBS involves giving your baby the nutrition they need in a way that supports their recovery. In the initial stages of NEC, babies may be fed through a tube or receive nutrition directly into a vein. This is called parenteral nutrition and is often used to make sure babies receive enough energy and nutrients while their bowel heals.⁴

Over time, the bowel can adapt and absorb more nutrients. Tube feeding may continue for weeks or months, depending on your baby’s progress.⁵ Medicines might also be given to reduce diarrhoea, help slow down digestion or decrease stomach acid.

In severe cases, when the remaining bowel cannot absorb enough nutrients, surgery may be considered. Procedures may include bowel lengthening or even a bowel transplant, although these are usually a last resort.⁶

With proper support and care, many babies with SBS go on to grow well. Their bowel may gradually adjust, allowing them to move on to more normal feeding routines over time.⁷

Intestinal strictures

What is an intestinal stricture?

An intestinal stricture is a narrowing of the bowel. This usually happens after the intestine has been inflamed or damaged, like in NEC. As the tissue heals, it can form scar tissue that tightens the bowel and makes it harder for food and waste to pass through.⁸

Strictures can occur several weeks or even months after a baby has recovered from the initial illness. While NEC most often affects the small intestine, strictures are more common in the large intestine.

Symptoms of strictures

Your baby may show symptoms such as vomiting, bloating, constipation, or feeding problems. These symptoms might be mild at first but can get worse over time. If the stricture becomes too narrow, it can cause a full blockage in the bowel, which is a medical emergency.

Diagnosis

Doctors might use special scans or imaging tests to find out if a narrowing, called a stricture, is present. One common method is a contrast study, where a special liquid is given to your baby to drink (or passed through a tube). This liquid shows up on X-rays and helps highlight any narrow sections in the bowel.⁹ In some cases, doctors may also use ultrasound or MRI scans for a clearer view of the intestines.

Treatment

In most cases, strictures need to be treated with surgery. The narrowed section of the bowel is removed, and the healthy ends are joined together. This can help relieve the blockage and allow food and waste to pass through more easily.

After surgery, your baby may need to be fed through a tube or drip while their bowel heals. Feeding is restarted slowly and increased as your baby improves. Your medical team will monitor your baby closely during this time and make sure they are recovering well.

Sepsis

What is sepsis?

Sepsis is a serious and sometimes life-threatening reaction to infection. It occurs when the body’s immune system becomes too active, causing widespread inflammation. In newborns, this condition is called neonatal sepsis. It can affect the heart, lungs, brain, kidneys, and other organs if not treated quickly.¹⁰

Babies born early or with low birth weights have a higher risk because their immune systems are still developing and not yet strong enough to fight infections. Sepsis can also happen after NEC if bacteria enter the bloodstream through a hole in the bowel wall.¹¹

Symptoms of sepsis

Signs of sepsis in babies can be difficult to spot at first. They may include a high or low temperature, difficulty waking up, breathing problems, pale skin, poor feeding, or a fast heart rate. In more severe cases, your baby might have seizures, extremely low blood pressure, or difficulty staying awake.¹²

Sepsis can progress quickly, so if you notice any of these symptoms or feel something is not right, seek medical help immediately.

Diagnosis

Doctors will check your baby’s condition and perform various tests. These can include blood tests and cultures to look for bacteria, a lumbar puncture to check for meningitis, and scans to help find where the infection is coming from.

Treatment

Sepsis is always treated as a medical emergency. Babies with sepsis are usually cared for in a NICU. They are given antibiotics intravenously to fight the infection. They may also receive fluids, oxygen, or breathing support, depending on how unwell they are.¹³

Other treatments may include help with feeding, keeping warm, and maintaining normal blood pressure. With fast and appropriate treatment, many babies can recover fully from sepsis. Some may need longer-term care depending on how serious the illness was.

There are ways to reduce the risk of infection, such as maintaining good hygiene and, in some cases, giving preventive antibiotics during labour. Breastfeeding can also help protect babies by passing on helpful antibodies from the mother.¹⁴

Summary

Necrotising enterocolitis (NEC) is a severe condition primarily impacting premature infants, leading to inflammation and harm to the intestines. If not addressed quickly, NEC can result in serious complications, such as short bowel syndrome (SBS), intestinal strictures, and sepsis. 

SBS arises when a large part of the small intestine is taken out due to extensive damage, leading to insufficient nutrient absorption and challenges with feeding. Infants with SBS frequently need specialised feeding assistance, like parenteral nutrition, whilst their intestines adjust. Intestinal strictures, which are narrowed areas of the bowel, can appear weeks or months following recovery from NEC. These can lead to symptoms such as vomiting, constipation, and abdominal bloating and usually require surgery to remove the damaged section of the intestine. Sepsis is a potentially fatal reaction to infection and can arise if bacteria enter the bloodstream via an injured bowel wall. Symptoms include difficulties in breathing, fluctuations in temperature, and fatigue, requiring immediate treatment with antibiotics and supportive care in a neonatal intensive care unit.

Despite these challenges, numerous infants tend to recover successfully with appropriate medical attention. Parents receive constant assistance through regular follow-up visits and advice from healthcare professionals to support them in managing their baby's recovery and long-term well-being.