Condition: Hirschsprung Disease (aganglionosis, Hirschsprung’s disease)
Overview ("What is it?")
- Definition: Hirschsprung disease is a developmental disorder of the nerves of the intestine. The intestine contains nerves in its wall. The nerves transmit signals to the muscle of the intestinal wall that allow the intestine to move its contents forward for digestion and removal (stooling). The specific nerves of intestinal movement are called “ganglion cells". In Hirschsprung disease, there are no ganglion cells in the wall of the affected intestine. 80-85% of children with Hirschsprung disease have the rectum and distal colon (large bowel) affected. Sometimes, a longer segment of colon, the entire colon, or even part of the small intestine may have absent ganglion cells.
- If the nerves or ganglion cells are not present in a part of the intestine, that intestine does not move things through. The affected area acts like a blockage. The baby can have a swollen belly, vomiting and inability to have stools on their own.
- Epidemiology: The incidence is about 1:5,000 children. Ganglion nerve cells are derived from special cells called neural crest cells that travel down the intestine during development. They are thought to travel from upper to lower intestinal tract. In Hirschsprung disease, this process is disturbed and the nerve stops traveling all the way down the anus. The exact reason this happens is not known.
Signs and Symptoms ("What symptoms will my child have?")
- Early signs: Intestinal blockage in a newborn baby: 50-90% of children present during the neonatal period with a swollen belly, vomiting when feedings are attempted and no passage of stool for the first 24 hours of life.
- Enterocolitis: 10% of children with Hirschsprung disease present with an intestinal infection (enterocolitis). Since the stool is not evacuated effectively out of the body through bowel movements, bacteria multiplies in the intestines. This results in fever, abdominal swelling, diarrhea or no stools, and even spread of bacteria into the blood. Enterocolitis maybe seen in infants or older children.
- Perforation: Because the distal bowel cannot relax and decompress, the normal intestine cannot empty its contents. It becomes very distended and can rupture (perforate). There will be air and stool leaking into the abdominal cavity and this can be diagnosed on X-ray. The surgeon will recommend emergent surgery.
- Later signs/symptoms:
- Chronic constipation: Some children with Hirschsprung disease present later in childhood with chronic constipation. This is most common in breastfed infants that typically develop constipation around the time of weaning. Clinical features in older children include failure to thrive, abdominal distension and dependence on enemas, suppositories or “rectal stimulation” to pass stool. Unlike older children with behavioral associated constipation and stool holding, children with undiagnosed Hirschsprung associated constipation generally do not soil their underwear.
- Several other congenital anomalies and genetic conditions are associated with Hirschsprung Disease. These are rare, but if your child has one of these diagnoses, they may have a higher likelihood of Hirschsprung disease. These are:
- Down syndrome (trisomy 21)
- Waardenburg-Shah syndrome
- Smith-Lemli-Opitz syndrome
- Congenital hypoventilation syndrome
Diagnosis ("What tests are done to find out what my child has?")
- The diagnosis of Hirschsprung disease is based on the clinical history, X-ray studies and a rectal biopsy.
- Plain radiographs may suggest a distal bowel blockage.
- Water-soluble contrast enema: In this study, a tube is gently placed in the rectum. Liquid dye (contrast) is injected to see if there is a narrowing of intestine (area where the nerves are not present) along with a distended intestine above the abnormal segment. This region is called where there is a difference in caliber of intestine (narrow abnormal segment and dilated normal segment) is called the “transition” zone—the transition between the narrow distal bowel with no ganglion cells and the proximal dilated colon. The study indicates approximately the length of colon without ganglion cells.
- A suction rectal biopsy is a procedure usually done at the bedside where a small instrument is inserted in the anal opening, pushed in about 2 cm and pieces of the intestinal lining is sampled (biopsy). These biopsies are sent to pathology where the presence or absence of nerves are confirmed under a microscope. In older children, a larger segment is needed (full thickness rectal biopsy). This is done under anesthesia.
- Manometry: This test is usually performed by a pediatric gastroenterologist (specialist). In this study, the relaxation of the sphincter muscle will be measured. Lack of relaxation is suggestive of Hirschsprung disease.
- Conditions that mimic Hirschsprung Disease: In infants: meconium plug syndrome, meconium ileus. In bigger kids, regular constipation can mimic Hirschsprung disease.
Treatment ("What will be done to make my child better?")
The treatment of Hirschsprung disease is surgical, but there are a number of preoperative interventions that must be considered prior to definitive operation.
- Medical treatment: If the child has evidence of enterocolitis (infection), the first priority is fluids and antibiotics. If the baby is vomiting and/or the belly is distended, nasogastric tube is placed. Children with enterocolitis or those in whom immediate surgery cannot be done for other reasons should undergo bowel decompression by rectal irrigations, removing the stool and bacteria from the intestine.
- Surgery: The timing of the definitive surgery for Hirschsprung differs in certain situations. In some centers, definitive surgery is performed in a baby once the diagnosis is made. In other centers, definitive surgery is postponed until the baby is bigger. In this case, the baby goes home on rectal irrigations in order to evacuate stool.
- Stoma: A temporary stoma may be necessary in certain situations. A stoma is a surgery that sews the end of the colon to the abdominal wall so that a bag can be applied for the stool to drain. For children with severe enterocolitis, perforation (a hole in the bowel from high pressure), poor nutrition, or an older child with extensively dilated proximal bowel, a temporary stoma may be recommended.
- Pull-through procedures: A “pull-through procedure” is the definitive procedure for HD. The main goals of this procedure are to remove the abnormal segment of bowel that has no nerves and connect the normally innervated segment of intestine to the anus. There are several operations to accomplish these goals (names are Soave, Swenson and Duhamel). Which type of pull-through is best for your child depends on many factors and will be discussed by your surgeon. The pull-through procedures can be done using open on minimally invasive (laparoscopic) approach.
- Laparoscopic surgery: In laparoscopic surgery, several small cuts (incisions) are made. Through one of the cuts, a video camera is placed. The surgery itself is done using small instruments placed through the other incisions. The usual number of incisions (cuts) for laparoscopic surgery vary.
- Open surgery (laparotomy) uses larger incision, either vertical or transverse to perform the operation.
- Long-segment disease: This is usually defined as lack of ganglion cells to the mid-transverse colon area (half the large bowel). At times the entire colon can be involved. There is often a positive family history. The surgeon may suspect long-segment disease from the appearance of the contrast enema. The rectal biopsy will have absent ganglion cells, but may also have other subtle differences.
- Once the level of ganglion cells is determined, most surgeons create a stoma, wait for complete pathology reports and plan reconstruction at a later date.
- The surgeon will discuss the details of the particular pull-through recommended, based on their experience. For total colonic involvement, a straight pull-through is frequently done. Although stool output may be high at first, this will decrease over time.
- Risks of surgery: The surgeon will observe for the following possible complications:
- Wound infection
- Anastomotic leak: The rectal sutures leak and cause infection
- Stricture (scarred narrowing of the rectal suture line)
- Bowel obstruction: Can be due to an adhesion, a twist in the pull-through or the rectal cuff where the bowel is pulled through can scar tightly and cause a blockage. The child will have a distended abdomen and vomiting.
- Fistulas: Connections between bowel and bladder or bowel and vagina have been reported to develop after operation. These are rare problems.
- Benefits of surgery: Ability to evacuate stool normally.
- Near Total Intestinal Aganglionosis: Rarely, almost the entire intestinal tract has no ganglion cells, leaving only 10-40 cm of normally innervated small bowel. In most of these cases, there is not enough functional small bowel to support nutrition and growth. These children must be fed from birth through the vein with total parenteral nutrition. The surgeon may recommend a stoma in the area where there are ganglion cells. These children are considered to have intestinal failure. They require detailed care from physicians, usually pediatric gastroenterologists, with experience caring for intestinal failure patients.
- Older children: Children diagnosed later in childhood may have an extensively dilated colon. Usually the dilated portion is removed, the level of ganglion cells is determined, a temporary stoma is done. This allows the dilated bowel to shrink. A pull-through operation is planned for a later date when the bowel is more decompressed.
- Preoperative preparation: If the operation is scheduled (elective), a bath or shower is recommended the night before or the morning prior to surgery. The child will not eat anything for 6-8 hrs before surgery. Intravenous antibiotics will be given in the operating room.
- Postoperative care: Once the child has stool out of the bottom or stoma, diet is resumed. Activity is normal. Medications for pain will be given.
Home Care ("What do I need to do once my child goes home?")
- Diet: Your child may eat a normal diet after surgery.
- Activity: Your child should avoid strenuous activity and heavy lifting for the first week after laparoscopic surgery, 4-6 weeks after open surgery.
- Wound care: Surgical incisions should be kept clean and dry for a few days after surgery. Most of the time, the stitches used in children are absorbable and do not require removal. Your surgeon will give you specific guidance regarding wound care, including when your child can shower or bathe.
- Medicines: Medicines for pain such as acetaminophen (Tylenol®) or ibuprofen (Motrin® or Advil®) or something stronger like a narcotic may be needed to help with pain for a few days after surgery. Stool softeners and laxatives are needed to help regular stooling after surgery, especially if narcotics are still needed for pain.
- What to call the doctor for: Call your doctor for worsening belly pain, fever, vomiting, diarrhea, problems with urination or if the wounds are red or draining fluid.
- Follow-up care: Your child should follow up with his or her surgeon 2-3 weeks after surgery to ensure proper postoperative healing.
- The surgeon will check the anastomosis (rectal stitches) at about two weeks after the pull-through. Some surgeons teach the parents how to dilate the anastomosis so it does not become narrow.
- Barrier cream: This is needed for some time, as diaper rash can be severe.
- Enterocolitis (see above)
- Back pressure on a colonic biopsy site can cause it to perforate.
Long-Term Outcomes ("Are there future conditions to worry about?")
- Occasional problems related to the bowel are fairly common in the first few years of life. The surgeon will follow the child until after the toilet training process, longer if needed.
- Ongoing obstructive symptoms: There are a range of obstructive symptoms that can occur after a pull-through.
- Mechanical obstruction
- Stricture: If the anastomosis scar tightens and narrows, sometimes it can be dilated. Surgery may be needed.
- Twist: If a twist in the pull-through is identified, surgery will be needed to correct it.
- Persistent aganglionosis: This is usually due to a pathologist error or lack of blood flow/inflammation of previously normal bowel causing nerves to die. A repeat biopsy may show that the pull-through was performed in an area without ganglion cells. Surgery will be needed to place the pull-through at the correct level.
- Motility Disorder: Children with Hirschsprung disease have a higher incidence of dyscoordination of the propulsive waves through the bowel (motility disorder) despite no obstruction, and normal ganglion cells in the rectum after pull-through operation. They may benefit from evaluation by a pediatric gastroenterologist and recommendations for bowel management.
- Internal sphincter achalasia: All children with Hirschsprung disease have an absent rectal inhibitory reflex, (the sphincter may not relax normally), but it is unclear why some develop obstructive symptoms from this and some do not. Sometimes the sphincter is tight, the bowel dilates and the patient has obstructive symptoms. Most outgrow the problem by age five years. The surgeon may recommend Botox injection of the sphincter. Botox relaxes the sphincter, but is only good for a few months. This diagnoses and treats the problem, and is generally successful.
- Functional megacolon: Stool-holding behavior is a common cause of constipation after pull-through operation. Passing hard, painful stools can start a cycle of withholding behavior. A bowel management program may be recommended.
- Soiling: The surgeon may recommend investigations to have a clear understanding of the cause of the soiling. Physical exam including rectal exam, X-rays, contrast enema and manometry may be recommended. The surgeon will determine the intactness of the sphincter and degree of normal rectal sensation. A treatment plan will be developed based on whether the soiling is due to a sphincter problem or rectal sensation problem, slow transit through the bowel with overflow of stool, stool holding behavior with overflow, or hyperperistalsis (rapid transit of stool due to abnormal motility).
- Enterocolitis: Enterocolitis may present both before and after surgical correction of Hirschsprung disease. It may present in children after operation who never had it preoperatively. It is the most common cause of death in children with Hirschsprung disease. It is more common in younger children, those with long segment disease and children with Down’s syndrome. The symptoms include fever, distension and diarrhea. X-ray abnormalities are present. Treatment involves nasogastric drainage, antibiotics, intravenous fluids and decompression of the colon and rectum, usually by irrigations. Enterocolitis can be minimized by the routine use of irrigations. Some surgeons also prescribe a regular dose of an antibiotic. If any of the above symptoms occur, the surgeon or a physician should be contacted immediately.
- Mechanical obstruction
- Resolution over first five years: Obstructive symptoms, soiling and enterocolitis (in the absence of obstruction), usually resolve in the first five years of life. Studies of teenagers suggest social satisfaction and quality of life normalize by the late teen years.
- Ongoing incontinence, enterocolitis and dehydration are more common in children with long-segment disease, Down’s syndrome or other causes of neurological impairment. Their long-term results are less satisfactory.