• Normal bowel habit (frequency of bowel motions) varies greatly from person to person.

  • For 9 out of 10 people this is between one bowel motion every 3 days to 3 bowel motions per day.
  • A bowel habit outside of this range is more likely to be abnormal.
    
    

• Constipation can be defined as

  • Having  less than one bowel motion per 3 days and having symptoms of abdominal bloating, lower abdominal discomfort and nausea.
  • AND / OR a sensation of difficulty passing a bowel motion with excess straining and hard bowel motions.
  • It is possible to have significant constipation even with a bowel movement once per day if that movement is small or ineffective.
  • This is usually, but not always, associated with the symptom of incomplete emptying. That is a feeling that there is "still more to pass".
  • Sometimes there is a sensation of a "blockage" with straining. This problem can be defined as "obstructed defecation". This symptom usually relates to problems with co-ordination of pelvic floor muscles or to underlying problems such as prolapse of the rectal mucosa or a rectocoele (section on "obstruction" for further details).
    
    
    

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• Management is discussed in detail in the next sections
  
  

• There are a wide variety of treatment options
  
  

• The simple advice to have a high fibre diet, take plenty of water and have regular excercise can be helpful for many but if this doesn't work then you need to read on...!!
  
  

• My pick for best three laxatives suitable for long-term use

• Kiwi Crush  - a glass a day of concentrated kiwi fruit juice - or simply kiwifruit juice (e.g Nekta - can be combined with aloe vera juice)
• Molaxole  (active ingredient - macrogol or PEG; previously called Lax-sachets or Movicol) -  a sachet of powder that draws in or retains water in the colon
• MgLax  - a capsule containing Mg  - like old-fashioned Epsom salts in a capsule (more details in section on osmotic laxatives)
  
  
• Constipation is more common in the elderly (see section).
• Many people find that they develop constipation with travel (see section).

A plain abdominal Xray can show the extent of constipation. Faceal loading throughout the colon suggests slow transit constipation

Causes of constipation.

• Mild and temporary symptoms may result from
  • Dietary changes.
  • Travel or a period of inactivity or immobility.
  • Inadequate fluid intake.
• Life-long constipation (starting from childhood or early adult) is a different issue (see below)
  • This is usually due to slow transit of colon.
  • There is an inherited (maybe) abnormality of the muscular activity of the colon.
  • There is a generalised problem with the colon. This means it is not just the process of defaecation that is affected.
  • The transit time around the colon is prolonged. The frequency of bowel motions can be relatively normal but with small and ineffective bowel motions.
• Constipation can be part of irritable bowel syndrome or diverticular disease.
  • In this situation there is more variability of bowel habit (episodes of diarrhoea as well) and lower abdominal cramping pain.
  • Gentle laxative treatment can be considered but may need to be stopped if diarrhoea becomes troublesome
  • Refer directly to these topics.
• Constipation may also associated with painful anal conditions, in particular anal fissure.
  • Bowel habit is inhibited because of the "knowledge" that it will be painful to pass the motion.
• Some medications can cause constipation.
  • "Pain-killers" - particularly Codeine, Paradex, Tramol, Morphine elixer or capsules.
  • Calcium channel blockers for hypertension (Verapamil, Diltiazem).
  • Some antidepressants (e.g. Amitriptyline, Nortriptyline).
  • Antispasmodics - given for "colic" e.g Buscupan, Merbentyl, Colofac.
  • Aluminium-containing antacids.
  • Calcium supplements.
  • Iron tablets.
  • Diuretics (fluid tablets usually given for hypertension).
• Other causes.
  • Depression can aggravate to an existing problem.
  • Low level of thyroid hormone (hypothyroidism).
  • Diseases of the spinal cord disease (particularly in the lower back).

Life-long constipation (usually slow transit constipation).

• The dominant problem is slow movement of faeces around the colon (large bowel) rather than a problem with the process of actually going to the toilet (defaecation)
• This could be termed "lazy bowel" or a "slow" colon.
• Usually the diagnosis is suggested by a history starting in teenage years or early 20’s.
  • The problem is more common in females.
  • Often there is a family history (mother or grandmother has similar problems).
• For most people minimal investigation is required.
  • Sometimes the diagnosis is clear from abdominal examination that shows loading or distension of the colon on both sides of the abdomen
  • A blood test for thyroid function and blood test for calcium should be done.
  • An abdominal X-ray is most useful to show "loading/fullness" of all of the colon with faeces.
  • This X-ray can be a baseline examination and follow-up X-rays can show if there has been improvement with treatment.
  • The diagnosis can also be suggested if usual bowel preparation for colonoscopy does not work and extra bowel cleansing fluid is required
• If there are relatively recent problems with constipation then the colon should be inspected by colonoscopy. Usually the colonoscopy will be normal.  Sometimes the colon is long and redundant ("floppy") suggesting rediced muscle tone and activity.
  
  
• A colonic transit study will confirm the diagnosis but is not usually required.
  • This involves swallowing marker beads and then plain X-rays of the abdomen over 5 days.
  • OR involves a nuclear medicine study with scans on a daily basis that follow a radio-labelled meal.

An excellent easy way to take kiwifruit all year round. One glass of juice equals 3-4 whole kiwifruit

Fibre and fibre supplements

• A high-fibre diet, regular exercise and increased fluid intake may help simple diet-related transient constipation but often has no effect for more long-standing symptoms.
  • The benefits of increased fluid intake are modest - perhaps no help for many people.
  • It is common for a high fibre diet to aggravate symptoms of bloating and abdominal discomfort.
• Fibre supplements (available from the chemist).
  • May be derived from Psyillium  husks (Plantago ovata)  (Metamucil, Konyl D, Mucilax and numerous other products) or sterculia (Normacol).
  • Metamucil is easy to take because it can be dissolved easily into a flavoured drink but may be more likely to increase bloating and wind
  • Normacol is more insoluble fibre (inert) and may be less likely to aggravate abdominal bloating i.e less fermentable by colonic bacteria. Normacol plus contains a stimulant laxative (frangula bark). This has an effect similar to cascara and senna (see stimulant laxative section).
  • Another fibre option is resistant starch.  A popular product is wheat dextran (marketed as Benefibre).  This is easy to take but will often cause increased abdominal bloating.  There is some theoretical evidence of benefit (as a prebiotic) but no clinical studies support this concept
• Fibre is actually only a modest laxative and sometimes the side-effects outweigh the benefits.
• The health advantages of fibre have been over-emphasized.  The evidence for prevention of bowel cancer and diverticular disease is modest and no other health benefits have been proven

Dietary changes(other than fibre)

• Kiwifruit.
  • This is best natural laxative. The effect has been confirmed in clinical trials and starts at a dose of 2 kiwifruit a day  - green kiwifuit may be better but gold also has some effect
  • Take as fresh fruit in season.
  • Available as Kiwi Crush – a freeze-dried or frozen concentrate - made by Nature's Spark.
  • Other brands of kiwifruit drinks are also available in the supermarket. A good product is produced by Nekta - there is a combination of Kiwifruit juice with aloe vera
• Prunes or prune juice.
  • This has some activity for some people.
  • Other food items with some effect are figs, dried fruits.
  • These options tend to aggravate bloating and wind.

Natural and Herbal products.

• Some reasonable options include
  
  • Aloe Vera juice has a mild laxative effect as well as some anti-spasmodic effect. This may be useful if cramping pain is prominent
  • Slippery Elm has a modest laxative effect.
  • Flaxseed oil (see www.theshop.co.nz (choose health post) or www.goodhealth.co.nz).  Modest laxative effect
  • Phloe is a product derived from kiwifruit.  It is a concentrate of zyactinase - considered to be the active enzyme in kiwifruit.  This is combined with some other plant-based enzymes or a low dose probiotic. This has no advantages over taking kiwifruit or the whole fruit products  (Kiwi Crush, Nekta juice).
  • My impression is that it has less activity than these other kiwifruit options. 
  • Another product is Bio Biotics (made by Life Stream) - this has a prebiotic (inulin), psyllium and a probiotic (low dose).  Prebiotics increase the supply of butyrate to the colon  -  the result of bacterial breakdown of a larger molecule  - this is of theoretical advantage only and has problems with excess wind formation.  The effect on constipation will be minimal
  • Herbal combinations that contain bowel stimulants (see next section on "stimulants") should be avoided e.g containing senna, cascara unless discussed with your doctor.  Examples include LBS II, Cascara sagrada, Bowel Build, BP-X.  Look at the ingredients list!  See alternative treatments section for more details

Pigmented appearance of colon that results from long term use of stimulant laxatives like Senna. See text for more details

Example of suitable magnesium capsule

Example of suitable Magnesium capsule

Senna is a herb that has been used as a laxative for centuries. It is a stimulant laxative with all the disadvantages discussed in the section

Molaxole is the funded sachet in NZ containing macrogol. This is am excellent and safe option for long term treatment

Different types of "laxatives"

The term "laxative" means any agent that helps constipation.  The negative view of laxatives comes from the possible long-term risks of stimulant laxatives (see below)

Lactulose

• This is sweet tasting syrup that is available on prescription.
• It is a non-absorbed large sugar molecule.
• This is an effective option and suitable for long-term treatment.
• There are often problems with aggravation of bloating and leakage of faeces at higher doses
• It is safe for long-term use and is suitable for diabetics as there is no absorption of sugar.

Stool softeners.

• Stool softeners (e.g. Coloxyl) are not much help.
• They are used mainly for treatment of painful anal conditions.
  
  

Stimulant laxatives

• This group includes;
  • Senna (Coloxy with Senna, Sennapod, Senakot, Laxsol, Alpine tea).
  • Cascara
  • Bisacodyl (Dulcolax tablets and Microlax enemas).
  • Frangula bark (additive in Normacol plus)
• They are present in various herbal combinations (e.g Alpine Tea).
• They are effective laxatives but can cause cramping abdominal pain.
• There is a possible risk of long-term damage to myenteric plexus – the nerves that stimulate the muscles of the colon.
  • The degree of risk may have been over-emphasized in the past.  The advice for many years has been to reserve these drugs for short-term use only.
• For some people with slow-transit constipation these stimulant laxatives appear to be the only effective treatment. It is usually possible to change treatment to an osmotic laxative (details below)
  
  • If used for long-term treatment the dose should be limited.
  • I suggest an acceptable maximum dose of 2 tablets of Coloxyl with Senna (Laxsol) 2-3 x weekly.
  • It is important that the dose remains low - this may be achieved by using combinations of treatments rather than relying solely on stimulant laxatives.
• There is a change in the lining of the bowel called melanosis coli.
  • This is usually seen at colonoscopy (see picture). This is due to long-term use of stimulant laxatives.
  • This change in itself is not hazardous but I generally take this to be a warning that an acceptable dose has been exceeded and that other ways of managing constipation need to be sought
    
    
• Stimulant laxatives should be avoided with irritable bowel and diverticular disease as they will aggravate abdominal pain

Osmotic laxatives

They work by drawing in water into the colon.  This is achieved by taking an inert compound that is not absorbed

They are very useful treatments for long-standing constipation

Magnesium capsules

• Magnesium salts are an old-fashioned treatment (Epsom salts) but this was a relatively unpalatable option.
• MgLax (Good Health) is a capsule that contains magnesium and aloe vera. This contains 400mg of elemental magnesium
• Heatheries High Strength Magnesium 400mg is an alternative product with similar amounts of elemental magnesium
• Maintenance dose is 1-3 capsules per day.
• Magnesium is safe for long term use - except if there is renal disease
• The effect can take to several days to start and the best maintenance dose may take some weeks to work out (through trial and error - "titration").  If this leads to diarrhoea then this is good news - it means the magnesium is effective and a lower maintenance dose may prove effective without causing unacceptable diarrhoea
• Serum magnesium can be measured if there are concerns but high magnesium levels are rare (only with significant renal disease). It is the non-absorbed magnesium that causes the laxative effect - therefore doses higher than the daily requirement need to be given (400 - 800 mg elemental magnseium.  Other magbesium products can be used. It is important to compare doses of elemental magnesium  - many products simply state the wait of the salt (magnesium plus stearate for example) which will  give a significantly higher weight in mg.

Molaxole sachets

• Formerly known as Movicol  or Lax-sachets
• One sachet is dissolved in water and taken once per day.
• Two sachets daily may be required to relieve severe constipation. 
• Once the “blockage” has been cleared then a maintenance dose of 1 sachet every 1-2 days may be enough. Maintenance does above 2 sachets daily are rarely required. Specialist review is required if higher doses are not working.
• These sachets are very convenient to take on holidays if travel is the initiating event for constipation. 
• The sachets are available on prescription without special authority or can be purchaed directly from the chemist.  The price has reduced significantly with a brand switch.
• For difficult constipation combinations of treatment may be required. The combination of Molaxole ( sachets per day) and a magnesium capsule as described above  (2-3 caps per day) is often effective for very resistant constipation.  This may be required if there has been long term dependence on stimulant laxatives

Constipation in the elderly

• Constipation is more common in the elderly.
  • There are age-related changes such as decreased sensation of need to defaecate and weakness of the muscles involves in defaecation
  • Other factors may be reduced mobility, impaired intellectual function, poor access to toilets, drugs (as per list above)and Parkinson’s disease.
• In the elderly faecal retention can lead to impaction of faeces in the rectum.
  • This gives the impression of diarrhoea (sometimes called overflow diarrhoea).
  • There is the leakage of loose faeces around an obstruction caused by impacted faeces. This can lead to faecal incontinence.
  • There may be a mistaken diagnosis of diarrhoea and treatment with anti-diarrhoeal medication is given which further aggravates the problem.
  • The diagnosis is obvious with a rectal examination.
  • The treatment is disimpaction with enemas and also lavage solution “from the top”.
• Severe constipation in the elderly may be missed.
  • Abdominal pain and distension may give the impression of a bowel obstruction.
  • Pressure on the bladder may cause urinary retention.
  • Restlessness or confusion may be the most obvious issues and the constipation missed.
• The most useful diagnostic test is a plain abdominal X-ray.

Travel constipation

• Many people find that they develop constipation with travel.
  • Usually there is a background of tendency to constipation at other times but this is manageable within the context of usual lifestyle.
  • Contributing factors are different toilet facilities, change in diet, stress and hectic schedules, dehydration with long haul flights.
  • A useful medication to take is Molaxole - convenient once daily sachets.
  • If the problem is predictable it is better to start early to prevent later problems during the trip.

Obstructed defaecation

• This means that there is a "functional blockage" when attempting to pass a bowel motion.
• It is important that there is investigation by colonoscopy to exclude any actual obstruction.
• "obstructed defecation" may be because the pushing forces are misdirected - perhaps due to a rectocoele (see below) or because there is prolapse of some rectal mucosa which forms a blockage in front of the bowel motions.
• A rectocoele is a bulge from the rectum into the vagina.
  • This is often part of a generalised weakness of the pelvic support.
  • It may be associated with a cystocoele - bulging of the bladder into the vagina.
• Risk factors are
  • Multiple or difficult deliveries; forceps or perineal tears.
  • A long history of constipation and straining.
  • A hysterectomy.
  • Mostly occurs post-menopausal.
• Symptoms include
  • A "bulging sensation".
  • Difficult evacuation with straining.
  • Sensation of incomplete emptying.
  • Improvement by pressing against the back wall of the vagina.
• Diagnosis is by a special X-ray called a defecating proctogram.
  • Barium paste is inserted into rectum.
  • X-ray pictures taken during defaecation.
  • Other tests may be required.  Anorectal manometry or pressure studies helps determine if there is inco-ordination of the pelvic floor and rectal muscles.  This may be able to be retrained using biofeedback techniques and pelvic floor excercises
• What treatments are available?
  • A trial of high fibre supplements should be considered. This may not work and may aggravate bloating.
  • Gentle laxatives other than fibre are worth a trial. i.e osmotic laxatives such as MgLax, Movicol
  • Surgical treatment should only be considered if there are troublesome symptoms and careful evaluation suggests that the rectocoele is the problem is the main option.
  • This is a repair called a rectoplexy. Surgical access to the rectum is usually through the anus but more sever cases require an abdominal (laparoscopic) approach.
  • There is an excellent graphic available on barclaygastro.com - interactive medicine - anorectal motility - large rectocoele and rectal intussusception / prolapse