CONSTIPATION
Colorectal Surgeons Sydney are experienced with a variety of Constipation conditions, including:
IRRITABLE BOWEL SYNDROME (IBS)
Irritable bowel syndrome (IBS) refers to a disorder that involves abdominal pain and cramping, as well as changes in bowel movements. It is not the same as inflammatory bowel disease (IBD), which includes Crohn’s disease and Ulcerative Colitis.
HOW IS IBS DIAGNOSED?
Irritable bowel syndrome (IBS) is a diagnosis of exclusion. This means that other causes for the symptoms of irritable bowel syndrome need to be first excluded before such a diagnosis can be made. This usually involves the need for a gastroscopy and colonoscopy to exclude certain pathology within the gastrointestinal tract.
Cause of IBS
There are many possible causes of IBS. For example, there may be a problem with muscles in the intestine, or the intestine may be more sensitive to stretching or movement. There is no problem with the structure of the intestine.
Stress can worsen IBS. The colon is connected to the brain through nerves of the autonomic nervous system. These nerves become more active during times of stress, and can cause the intestines to squeeze or contract more. People with IBS may have a colon that is over-responsive to these nerves.
IBS can occur at any age, but it often begins in adolescence or early adulthood. It is more common in women. About 1 in 6 people in Australia have symptoms of IBS.
Symptoms of IBS
Symptoms range from mild to severe. Most people have mild symptoms. Symptoms vary from person to person.
Abdominal pain, fullness, gas, and bloating that have been present for at least 6 months are the main symptoms of IBS. The pain and other symptoms will often:
- Occur after meals
- Come and go
- Be reduced or go away after a bowel movement
- People with IBS may switch between constipation and diarrhoea, or mostly have one or the other.
- People with diarrhoea will have frequent, loose, watery stools. They will often have an urgent need to have a bowel movement, which is difficult to control. This urge rarely wakes a person from their sleep.
- Those with constipation will have difficulty passing stool, as well as less frequent bowel movements. They will often need to strain and will feel cramping with a bowel movement. Often, they do not eliminate any stool, or only a small amount.
For some with IBD, the symptoms may get worse for a few weeks or a month, and then decrease for a while. For others symptoms are present most of the time and may even slowly increase.
Investigations for IBS
There is no test to diagnose IBS, but tests may be done to rule out other problems and include stool cultures to rule out infection of the colon (colitis), gastroscopy to rule out a disorder of failed absorption of the small bowel (celiac disease and lactose intolerance), and colonoscopy to rule out disorders of the colon such as colitis, diverticulosis, and cancer than can often mimic IBS.
Colonoscopy is particularly important for those with IBS symptoms who:
- had their symptoms begin later in life (e.g. over age 40-50)
- have symptoms such as weight loss or bloody stools
- have iron deficiency anaemia with a low haemoglobin.
Lifestyle treatment of IBS
Once the diagnosis has been established with a normal gastroscopy and colonoscopy, the goal of treatment is to relieve IBS symptoms.
Lifestyle changes can be helpful in some cases of IBS. For example, regular exercise and improved sleep habits may reduce anxiety and help relieve bowel symptoms.
Dietary changes can be helpful. However, no specific diet can be recommended for IBS in general, because the condition differs from one person to another. The following changes may help:
- Avoid foods and drinks that stimulate the intestines (such as caffeine, tea, or colas)
- Avoid large meals
- Avoid wheat, rye, barley, chocolate, milk products, and alcohol
- Increase dietary fibre
Medical treatment of IBS
Talk with your GP before taking over-the-counter medications. No one medication will work for everyone. Medications need to be tailored to meet the symptoms, which typically alternate in IBS. Medications your doctor might try include those used to treat non-infectious diarrhoea, such as diphenoxylate and atropine (Lomotil®) or loperamide (Imodium® or Gastrostop®). These medications work as a ‘chemical plug’ and must not be used if there is any chance that diarrhoea is due to infection.
If crampy pains are the main symptom, then medications that relax muscles in the intestines such as hyoscine (Buscopan®) may help. Fibre supplements can make symptoms worse, as they increase fluid consistency of stool and methane production leaking to crampy pain and diarrhoea.
Expectations for IBS
IBS may be a lifelong condition. For some people, symptoms are disabling and reduce the ability to work, travel, and attend social events. Symptoms can often be improved or relieved through treatment. IBS does not cause permanent harm to the intestines, and it does not lead to a serious disease, such as cancer.
SLOW TRANSIT CONSTIPATION (STC)
Slow transit constipation (STC) typically involves the unusually slow passage of faeces through the colon (large intestine). This can lead to chronic constipation and uncontrollable soiling. STC may mimic or coincide with Hirschsprung’s disease.
Diagnosis of slow transit constipation (STC)
The diagnosis of STC first involves confirming slow transit of faeces with “marker studies” in which the patient swallows a capsule containing either radiolabelled or opaque numbered markers that show up on x-rays taken repeatedly over several days or a week.
Ano-rectal causes of constipation due to obstruction need to be excluded. This includes short-segment Hirschsprung’s disease involving the rectum in which the nerves (ganglions) of the enteric nervous system of the colon and rectum (myenteric plexus) are missing. Hirschsprung’s disease can be excluded by taking a full-thickness rectal biopsy. It is also important to exclude other disorders of the rectum including a rectum that collapses on itself (rectal prolapse) or bulges excessively into the vagina (rectocele) or abdomen (enterocele) during straining, as these can all lead to a rectum that is unable to evacuate its contents (obstructive defecation). Weakness of the pelvic floor with excessive downwards movement on straining (pelvic floor descent) can similarly cause constipation due to obstructive defecation. All of these conditions can occur separately, or be combined (tetralogy of fallout). They are associated with classical symptoms, and these combined with a real-time x-ray taken during defecation (defecating proctography), will help suggest whether one of these conditions is responsible.
Medical management of slow transit constipation
Slow transit constipation can often respond to biofeedback and regular laxatives.
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Biofeedback
Biofeedback is a risk-free approach that has been reported as effective in approximately 60% of patients with slow transit constipation. Uncoordinated (dyssynergic) defecation is common and affects up to half of patients with slow transit constipation. It is due to the inability to coordinate the abdominal and pelvic floor muscles to evacuate stools. Biofeedback therapy teaches coordination of the abdominal and pelvic floor muscles, and positioning to encourage evacuation. It also involves the use of a prospective stool diary to encourage practices that promote regularity.
Several randomised trials have demonstrated that biofeedback is not only efficacious but superior to other modalities such as laxative or sham training.
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Laxatives
Stimulant laxatives such a bisocodyl (Bisolax®) are considered first-line therapy, beginning at 10mg twice a day. This can be combined with an osmotic laxative such as lactulose (Lactulax®) beginning with 30ml twice a day. There is no evidence to suggest that chronic use of such laxatives is harmful. Periodic use of bowel preparation solutions such as polyethylene glycol (Glycoprep®) may be needed.
Surgery for slow transit constipation
Surgery for slow transit constipation is a last resort, and indicated only in severe cases that have failed medical management. The surgical options include:
- sacral nerve stimulator (SNS), which is thought to result in chemical alteration (neuromodulation) of the nervous system of the colon (myentetic plexus),
- the insertion of a Chait tube caecostomy, that allows regular irrigation and evacuation of the colon, or
- a Total colectomy which the entire colon is removed, with small bowel joined directly to the rectum.
Constipation is a symptom that means different things to different people. Most commonly, it refers to infrequent bowel movements, but it can also refer to increased firmness of stool, the need to strain to pass a motion, and a sense of incomplete evacuation, or the need for laxatives, suppositories or enemas to maintain regularity.
Bowel movements once a day are ideal, but there is great variation in what is considered normal. Bowel motions anywhere between 3 times a day to 3 times a week are still within normal limits. Irritable bowel syndrome is a condition where features of constipation may exist with pain related to colon spasm. Slow-transit constipation is where to time taken for the stool to pass through the colon is documented to be excessively delayed.
ROLE OF DIET AND EXERCISE
Normal bowel movements are affected by diet, therefore someone who eats very little may not have a bowel movement for a week without experiencing discomfort or harmful effects. Normal bowel habits are affected by diet. The average Australian diet includes only 12-15g of fibre per day, which is half the recommended amount of fibre for proper bowel function. Eating foods high in fibre, including breakfast cereals (Weet-Bix®, ALL-BRAN®, and shredded wheat), whole grain breads and fresh fruits and vegetables will help provide the 25 to 30 grams of fibre per day recommended for proper bowel function. Exercise is also beneficial to proper function of the colon.
WHAT CAUSES CONSTIPATION
There are often multiple causes for constipation, including inadequate fluid intake and fibre, lack of exercise and environmental changes. Constipation may be aggravated by a change in diet, long periods of travel, and pregnancy. In some people, it results from chronically ignoring the urge to have a bowel movement.
More serious causes of constipation need to be excluded before a diagnosis of constipation is made. These include narrowings in the colon caused by repeated attacks of inflammation from diverticular disease or a cancer of the colon. Obstruction to defecation can also occur at the anorectum and this can be due to weakness of the pelvic floor and wall of the rectum resulting in the rectum collapsing on itself (intussusception) or ballooning out (rectocele). Other medical causes include a lazy bowel where there the normal bowel movements (peristalsis) of the bowel are impaired resulting in slow passage of stool along the colon (slow transit constipation).
WHAT MEDICATIONS CAN CAUSE CONSTIPATION?
Many medications, including opioid-based pain killers, antidepressants, tranquilizers, and other psychiatric medications, blood pressure medication, diuretics, iron supplements, calcium supplements, and aluminium-containing antacids can slow the movement of the colon and worsen constipation.
WHEN SHOULD I BE WORRIED ABOUT CONSTIPATION?
Any persistent change in bowel habit, increase or decrease in frequency or size of stool or an increased difficulty in evacuating warrants a review by your GP, and a digital rectal examination.
WHO SHOULD HAVE A COLONOSCOPY?
You should also be referred to a colorectal surgeon who will organise a colonoscopy if this has not already been done. If blood also appears in the stool, then this should be done sooner rather than later.
WHAT OTHER INVESTIGATIONS ARE NEEDED IF COLONOSCOPY IS NORMAL?
If colonoscopy is normal, then other tests may be needed to determine the cause of constipation. “Marker studies,” in which the patient swallows a capsule containing either radiolabelled or opaque numbered markers that show up on x-rays taken repeatedly over several days, help to confirm a lazy bowel (slow-transit constipation).
Other physiologic tests evaluate the function of the anus and rectum. These include tests that measure the innervation of the anus (pudendal nerve studies), the function of the anal muscles (endo-anal ultrasound and manometry), or x-rays that measure the emptying capacity of the rectum on straining (defecating proctography).
In many cases, no specific anatomic or functional causes are identified and the cause of constipation is said to be nonspecific.