Hirschsprung's disease

This is a condition present from birth in which the nerve cells never reached the last stretch of the bowel, so that stretch cannot relax. The contents come up against it as against a closed door, the bowel above it swells, and the baby develops severe constipation from the first days of life. It occurs in roughly one newborn in five thousand and several times more often in boys. The treatment is entirely surgical: the section that does not work is removed, and after that the bowel behaves normally. What deserves the most fear is not the operation but a bowel infection that can develop both before it and years afterwards.

Why the bowel stops pushing things along

The bowel wall does not contract on orders from the brain but through its own nerve clusters, which sit within its thickness. Those cells form in the embryo and gradually populate the bowel from the top downwards, all the way to the anus. In Hirschsprung's disease that journey stops halfway, and the lower stretch is left without nerve cells.

That stretch is not paralysed. On the contrary, it stays clenched and does not open in front of the contents arriving at it. The result is an obstruction with no mechanical barrier: the bowel is open but will not let anything through. Above it stool and gas build up, the wall stretches and the abdomen swells.

The length of the nerveless segment varies. Most often, in about four cases in five, it covers the rectum and part of the sigmoid colon. Less often the whole large bowel is involved, and in rare cases the small bowel as well; those forms run a harder course.

How it looks in a newborn

Most often the condition announces itself in the first days of life. The warning signs are:

• no meconium — the first dark, almost black stool — within the first twenty-four to forty-eight hours;
• a swollen, tight abdomen;
• vomiting of green or yellow-green material;
• refusing the breast or the bottle, and weak sucking;
• stool that only comes after a rectal tube is passed, and then arrives explosively, with wind and obvious relief.

It is worth knowing that in some babies the meconium does pass on time and the diagnosis comes later. Meconium having passed does not remove the suspicion if the baby empties poorly afterwards.

When the diagnosis comes later

If the nerveless segment is short, infancy can pass relatively quietly, particularly on breast milk, and the difficulties become obvious when solid food is introduced. In older children the picture is this: constipation present literally from birth that does not respond to the usual measures, a distended abdomen, pain, poor appetite, slow weight gain and sometimes anaemia.

It matters to tell this apart from ordinary constipation, which is incomparably more common. Functional constipation is suggested by an onset that is not from birth but later — usually around new foods, potty training or an upset — and by soiling of the underwear, because the stool sits in an overloaded rectum. In Hirschsprung's disease the rectum is instead empty and tight, and soiling hardly ever happens. That is the first thing the doctor weighs up.

Very short segments sometimes go unrecognised into adolescence and even adulthood, showing themselves as lifelong constipation with dependence on laxatives and enemas. Such a diagnosis in an adult is rare, but it exists.

Enterocolitis, the main danger

The most serious complication is the bowel inflammation associated with Hirschsprung's disease. Stagnant contents, a stretched wall and a broken barrier let bacteria into the depth of the bowel and from there into the blood. It develops quickly and can end in sepsis.

Call an ambulance (112 across Europe) or take the child to an emergency department if there is:

• a temperature of 38 °C or above;
• copious watery, foul-smelling or bloody stool;
• a markedly swollen, tense, painful abdomen;
• repeated vomiting, especially green;
• listlessness, drowsiness, pale or greyish skin, difficulty rousing the child;
• signs of dehydration: a dry mouth, little urine, a sunken fontanelle, crying without tears.

Two things parents are not always told. First, enterocolitis can occur before the operation and equally months or years after it, so these signs need to be remembered for a long time. Second, diarrhoea in this condition does not mean the blockage has cleared: liquid seeps past the solid contents, and stopping it with antidiarrhoeal medicines is not an option, because it is dangerous.

How the diagnosis is made

It starts with examining the abdomen and with a rectal examination: the doctor passes a finger into the anus and judges the tone and whether anything is there. In this disease the rectum is usually empty and grips the finger, and on withdrawal wind and stool often follow explosively.

After that come:

• an abdominal X-ray, which shows distended loops and the level at which the picture changes;
• a contrast study with the fluid introduced through the anus, showing the transition zone between the narrow nerveless segment and the widened bowel above it;
• anorectal manometry in older children: in this disease the internal sphincter fails to relax when the bowel is stretched;
• a rectal biopsy, which is the decisive test. A tiny piece of the lining is taken through the anus and examined under the microscope for nerve cells. That is how the diagnosis is made; everything else prepares for this step.

Where it comes from

The cause is a fault in development during the early weeks of pregnancy. Nothing the mother ate, no illness she had, no medicine and nothing that happened during the pregnancy brings it about: parents have nothing to blame themselves for, and that deserves saying plainly.

Several genes are involved, and the one mentioned most is the RET gene. The condition sometimes runs in families: once a child has been born with this diagnosis, the chance for later children is higher than average. In roughly one case in five it comes alongside other conditions present from birth, most often Down's syndrome.

There is also an uncommon situation worth asking the doctor about with regard to genetic testing: in some families, changes in that same RET gene are linked to an inherited tumour of the thyroid gland. This concerns a minority of cases, but a predisposition found in time changes the follow-up of a whole family rather than of the child alone.

The operation and getting ready for it

Treatment is surgical only: the non-working section is removed and healthy bowel is brought down to the anus. The operation is known as a pull-through and is carried out through the anus, through small incisions or by open surgery; the choice depends on how much bowel is affected and on the child's condition.

While preparations go on, the bowel has to be decompressed. This is done with washouts: a soft tube and warm salt solution are passed through the anus to soften and flush out the contents. Ordinary enemas and laxatives are no use here. If the child is seriously unwell, milk feeds are paused in favour of fluids into a vein, a tube is placed into the stomach to drain it, and antibiotics are added when there is enterocolitis. Parents are usually taught to do the washouts, and some children wait for their operation at home.

The surgery is sometimes divided into two stages. First the bowel is brought out onto the abdomen through a temporary opening, a stoma, and the stool collects in a bag. Once the inflammation settles and the child regains strength, the affected section is removed, the stoma is closed and the bowel is joined up again. This route is taken when there is enterocolitis, when the bowel is greatly dilated and when the diagnosis has come late.

As with any operation there are risks: bleeding, infection, failure of the join with inflammation of the abdominal lining, and narrowing at the suture line that needs stretching or a further procedure. How likely each of these is for your particular child is something to discuss with the surgeon beforehand.

What follows the operation

The child spends several days in hospital, receiving pain relief and fluids into a vein until eating and drinking start again. No special diet is needed at home; the only thing that matters is drinking enough.

For the first weeks the skin around the anus will be sore from frequent stools. Simple measures help: wash with warm water without soap and without rubbing, pat dry, leave the skin open to the air whenever possible, and apply a barrier cream at every nappy change.

From then on the bowel works normally in most children, though adjusting takes time. Constipation may occur and call for fibre, plenty of fluid and laxatives prescribed by the doctor; some children have faecal incontinence that persists into school age and the teenage years and upsets them greatly — this is a treatable problem, and it should be brought to a doctor rather than left in the hope it will be outgrown. Potty training often takes longer than in other children. A small proportion of children are left with a permanent stoma.

Follow-up continues for years. And the main point bears repeating: the signs of enterocolitis remain relevant after a successful operation too.

Online consultation

A remote appointment suits the questions this condition generates, and it generates a great many of them, continuously. Before surgery: working out whether the child's difficulties look like Hirschsprung's disease or ordinary constipation, and which investigations to ask for. Afterwards: going over the washout technique, the care of the stoma and of the skin, the laxative regimen, the pace of potty training and what to do about incontinence. Online you can show the discharge summary and the biopsy report and get a plain explanation of what they say. The signs of enterocolitis listed above are not dealt with remotely: those mean calling an ambulance at once or taking the child to hospital.

This material is for information only and does not replace medical advice.