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Causes of
constipation
History and
examination
Investigations
General practice
treatment
Specialist
intervention and
the GP’s ongoing
role
The authors
CONSTIPATION
DR VID SUTTOR,
gastroenterology advanced
trainee (final year) and motility
research fellow, gastrointestinal
investigation unit, Royal North
Shore Hospital, St Leonards,
and University of Sydney, NSW.
Background
WHEN constipation is described by
patients, it usually refers to the passage
of hard or infrequent stools, but each
patient’s perception of the problem
may differ. Constipation has been
defined by the International Rome
Committee for Gastrointestinal Disorders as being the presence of at least
two of the following symptoms for at
least one-quarter of the time:
■ Straining.
■
Epidemiology
■
Constipation is common in the general population, with a prevalence
of 15-20%. In patients under 50,
women are twice as likely to be
affected as men, while the prevalence converges in older age groups
(20% in men vs 25% in women).
Groups that are more likely to be
affected include the elderly, children, pregnant women, bedridden
Lumpy or hard stools.
Sensation of incomplete evacuation.
■ Sensation of anorectal obstruction.
■ Manual manoeuvres to facilitate
defaecation.
■ Fewer than three defaecations a week.
Some patients self-manage, but many
present to their GPs for additional help.
There is a subset that may need to be
referred for specialist management for
chronic refractory symptoms.
patients and those who have undergone certain types of surgery such
as gynaecological procedures.
In a NSW survey, only one-third
of the young women and half of
the middle-aged and older women
with constipation had sought help
for treatment of their condition, but
constipation still represents a major
reason for patients to present to
their GPs.
DR ALLISON MALCOLM,
staff specialist
gastroenterologist, department
of gastroenterology and
gastrointestinal investigation
unit, Royal North Shore Hospital,
St Leonards, and in private
practice in Chatswood, NSW.
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Causes of constipation
Dietary
DEFICIENCY of fibre and
fluids can frequently lead to
hard and lumpy stools that
can be difficult to evacuate.
For the general population,
Australian NHMRC guidelines recommend intake of
25g of fibre a day for
women, and 30g a day for
men.
NHMRC guidelines also
recommend 1.5L of water a
day for the general population, in mild climates. In
hotter parts of Australia or
with increased losses such as
with exercise, and especially
in patients with constipation,
a higher intake of fluid may
be needed to prevent dehydration, which can contribute
to constipation.
Medications
The onset of constipation
may be temporally linked to
starting certain medications,
and a careful review of the list
of medications needs to be
undertaken. Table 1 provides
a list of some medications
commonly linked to constipation, although a vast number
of medications may have GI
side effects in some patients.
Organic disease
Mechanical obstruction from
colorectal malignancy is
important to consider, given
the background prevalence of
colorectal cancer in the community (one in 12 up to age
85). Diseases affecting neurohormonal or structural factors that co-ordinate movement of stool through the
intestine can also lead to constipation (table 2).
Slow colonic transit
A subgroup of patients with
chronic constipation has slow
transit constipation (colonic
inertia), in which the underlying pathophysiology may be
related to neuropathy of the
colonic nerve plexus. This
Table 2: Causes of
constipation
Table 1: Common medications linked to constipation
Grouping
Examples
Antispasmodics
Hyoscine, mebeverine
Antipsychotics
Lithium, clozapine, olanzapine,
haloperidol
Analgesics
Codeine, oxycodone,
morphine
Antidiarrhoeals
Loperamide
Calcium-channel antagonists
Nifedipine, amlodipine
Antacids
Calcium carbonate-containing
antacid agents
Neurological disorders
■
Cerebrovascular accident
■
Spinal cord lesions
■
Multiple sclerosis
■
Parkinson’s disease
■
Autonomic neuropathy
■
Hirschsprung’s disease
■
Neurofibromatosis
Calcium supplements
Metabolic states/
disorders
Iron supplements
■
Diabetes mellitus
■
Hypothyroidism
■
Pregnancy
■
Hypopituitarism
■
Hypercalcaemia/
hypokalaemia
■
Porphyria
■
Paraneoplastic
group of patients can represent one-third of constipated
patients referred to tertiary
centres.
Colonic transit may also be
delayed because of organic
conditions or medications, as
well as variable factors such
as physical or emotional
stress, and disturbance of the
sleep-wake cycle. The
increased time for stool transit
through the colon allows
longer mucosal contact time,
leading to increased water
absorption from the stool and
hence harder stool consistency.
Simple
management
approaches and lifestyle modifications may not be sufficient for some patients with
severely delayed colonic transit, who often require use of
osmotic agents, and sometimes even (as a last resort)
subtotal colectomy (see Indications for surgery, page 38).
Excess straining.
■ A sense of anal blockage.
■ A sense of incomplete evacuation.
■ Use of digital manoeuvres
or unusual positions to facilitate evacuation.
Although stool reaches the
rectum, these patients cannot
evacuate effectively, so
symptoms of constipation
can result. This is because
such patients demonstrate
poor co-ordination of
abdominal, anorectal and
pelvic floor muscles, leading
to an abnormal defaecatory
manoeuvre.
As a result, they are either
unable to achieve adequate
rectal pressure to initiate
defaecation, or display either
absent anal relaxation or
paradoxical anal contraction
during defaecation (resulting
in a sensation of obstructed
defaecation, and often leading to constipation).
Pelvic floor dyssynergia
Functional constipation
A proportion of patients with
constipation have abnormal
or obstructed defaecation.
This is an acquired disorder
in most patients, although a
small proportion of patients
have not learned normal
defaecation adequately in
childhood. Symptoms of
pelvic floor dyssynergia
include:
The most widely accepted
definition of functional constipation, the Rome III criteria, is based on consensus
criteria developed by an
international panel of
experts. According to Rome
III, the following criteria
must be fulfilled for three
months, with symptom
onset at least six months
■
Collagen or muscle
disorders
■
Systemic sclerosis
■
Amyloidosis
■
Dystrophia myotonica
■
Dermatomyositis
Structural disorders
■
Colorectal cancer
■
Colonic stricture
Functional disorders
■
Functional constipation
■
Irritable bowel syndrome
■
Pelvic floor dyssynergia
■
Colonic inertia
before diagnosis of functional constipation.
1. Inclusion of two of the following:
a. straining for *25% of
defaecations.
b. lumpy or hard stools in
*25% of defaecations.
c. sensation of incomplete
evacuation after *25%
of defaecations.
d. sensation of anorectal
blockage during *25%
of defaecations.
e. manual manoeuvres for
*25% of defaecations.
f. fewer than three defaecations per week.
2. Loose stools rarely present
without use of laxatives.
3. Insufficient criteria for irritable bowel syndrome
(IBS).
Irritable bowel syndrome
with constipation
The defining feature of IBS is
the presence of abdominal
pain associated with, or
relieved by, defaecation. Of
course constipation may also
occur within the setting of
IBS, which is a common
condition, and this combination affects a significant
number of patients presenting to GPs.
Although IBS has been
known to account for up to
50% of patient referrals to
specialist physicians, a further
proportion of people with IBS
in the community defer seeking medical attention, either
because of embarrassment or
lack of confidence.
The ability of the treating
medical practitioner to establish a constructive therapeutic
relationship with the patient
has been shown to reduce the
level of frustration and hopelessness that patients often
experience. However, a successful outcome requires more
than just a good relationship
— an understanding of the
multifaceted nature of this
condition is also helpful.
While the aetiology and
pathophysiology of IBS are
still under investigation, disordered colonic motility, aberrant visceral sensitivity, and
altered neural processing of
gut stimulation are deemed to
be central mechanisms in the
evolution of this syndrome.
To date, pharmacological
therapy has been used to
target:
■ Improving abdominal pain
(resulting from visceral sensitivity and abnormal neural
processing).
■ Regulating the altered motility and sphincter function.
■ Altering the stool form to
facilitate defaecation.
In addition, medications to
manage psychiatric disorders
may also be needed, as concomitant depression and anxiety may contribute to poor
outcomes in patients with
severe IBS.
Overlapping disorders
Investigations of patients with
refractory constipation
referred to tertiary centres
have revealed a significant
degree of overlap in the
causes of constipation, with
slow colonic transit being
found in 47% of patients,
overlapping with visceral
hypersensitivity indicative of
IBS in 58%, and pelvic floor
dyssynergia in 59%. However, no physiological abnormalities are found in 24% of
patients, which is in itself
indicative of functional con1
stipation.
Hence patients diagnosed
with IBS on clinical grounds
should also be considered
for possible concomitant
causes of constipation, as
this may guide further
investigation and options for
therapy, eg, biofeedbacktherapy for functional constipation and pelvic floor
dyssynergia (see Specialist
intervention and the GP’s
ongoing role, page 38).
History and examination
History
A thorough history reviewing stool frequency
and consistency, current and past use of laxatives, and pelvic floor inco-ordination symptoms should be undertaken.
Patients may complain of straining to defaecate even with soft or watery stools, or may
define themselves as being constipated because
they have a sensation of anorectal obstruction
or pain. Occasionally patients may even present with diarrhoea or faecal incontinence
when severe constipation with ‘overflow’ is
present.
A review of background medical comorbidities and a medication history may provide a
clue to underlying organic pathology. A family
history of bowel dysfunction or laxative use
may be present in up to one-third of patients.
Further review of dietary history, including
fibre and water intake, timing of meals, and a
tendency to skip breakfast should be discussed.
After waking, a morning meal is the strongest
physiological stimulus of colonic motor activity, and a tendency to skip breakfast may have
repercussions for daily colonic transit.
A review of caffeine and alcohol intake
should be included in the dietary history.
Symptoms of anxiety or depression should
also be sought. Finally, a prior obstetric history and review of past surgical procedures,
including back operations, may also provide
a clue to the aetiology of the constipation. In
particular, it has recently been reported that
constipation is more common after hysterectomy.
Breakfast provides a
strong physiological
stimulus of colonic
motor activity.
Physical examination
Physical examination with palpation of the abdomen to check for
masses or a faecally loaded sigmoid colon, as well as a digital
rectal examination to examine
for faecal impaction, an anal
fissure, haemorrhoids or a rectocoele is essential. In addition,
a thorough general examination
including assessment for thyroid
disorders and neurological disorders such as Parkinson’s disease is
important.
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How to treat – constipation
Investigations
INITIAL blood tests should
include FBC, serum calcium,
blood glucose level and thyroid function testing. An
abdominal X-ray to look for
faecal loading may be useful
in some patients. A
colonoscopy should be considered in all patients with
warning signs for malignancy, such as:
■ Altered bowel habit.
■ Overt or occult rectal
bleeding.
■ Iron deficiency anaemia.
■ Loss of appetite.
■ A history of colonic polyps
or neoplasia.
■ A relevant family history
of colonic malignancy.
Barium enema can also
be useful in excluding
structural abnormalities, as
can defaecography for
detecting a rectocoele with
stool retention. Other
imaging such as CT or
ultrasound scanning should
be considered in cases with
abdominal distension if
there is suspicion of other
pathology such as ovarian
cancer.
Figure 1: A: Normal colonic transit study, demonstrating clearance of tracer by day 4-5. B: Slow colonic transit study, demonstrating persistence of tracer at day 5.
A
B
Anorectal manometry
Colonic transit study
A nuclear medicine colonic
transit study can provide
valuable information in
patients with chronic constipation when the above measures have been unhelpful.
For this study a radioactive
tracer mixed with water is
ingested, and clearance of
the tracer is assessed.
Figure 1A shows a normal
colonic transit study in
which there has been almost
complete clearance of the
tracer by day 4. Figure 1B
shows slow transit constipation, where much activity
remains in the colon even
after day 5. The identification of slow colonic transit
can help guide therapy for
these patients.
In patients with
symptoms
suggesting
pelvic floor
inco-ordination,
an anorectal
manometry study
can confirm the
diagnosis.
In patients with symptoms
suggesting pelvic floor incoordination, an anorectal
manometry study can confirm the diagnosis and allow
formulation of a management plan. A comprehensive
anorectal physiology study
uses a balloon attached to
pressure-sensing catheters
that provide information on:
■ The length of the anal
canal.
■ Resting and squeeze anal
sphincter pressures.
■ The degree of anal sphincter relaxation or paradoxical contraction on straining.
■ Rectal pressures on straining.
■ Rectal sensation.
The balloon expulsion test
involves inflating a rectal
balloon with 50mL warm
water then asking the patient
to expel this while seated on
a commode (to simulate
normal toileting behaviour).
Patients unable to expel the
balloon from the rectum
within 60 seconds are highly
likely to have pelvic floor
dyssynergia.
Anorectal manometry can
also exclude the diagnosis of
Hirschsprung’s disease.
Absence of normal reflex
relaxation of the internal
anal sphincter after distension of a balloon in the
rectum indicates absence of
mediation by the myenteric
plexus. Figure 2 demonstrates the layout in a typical anorectal manometry
laboratory.
Figure 2: Manometry-based biofeedback therapy clinic at Royal North Shore Hospital,
St Leonards, NSW.
General practice treatment
modalities
Diet, water and lifestyle measures
MANY patients with chronic constipation are unaware of
simple dietary modifications that can alleviate their symptoms. Increasing the amount of dietary fibre products, along
with NHMRC recommendations for two serves of fruit and
five serves of vegetables daily (1-2 serves extra of each in
pregnancy), and including cereal products (4-12 serves for
men and 4-9 serves for women daily) (table 3), should be
enough to provide daily fibre requirements.
However, some patients may require additional fibre, either
dietary or supplemental. Types of supplemental fibre include
psyllium (Metamucil), ispaghula husk (Fybogel), guar gum
(Benefiber) and sterculia (Normafibe).
The dosing for these agents starts at 1-2 teaspoons once or
twice daily with meals and can be adjusted according to the
patient’s needs. Most patients require at least 30g of fibre
daily, and a commitment of regular intake for at least one
week is needed to reach a steady state in terms of dosing and
result.
In addition, all fibre intake must be combined with adequate intake of fluid (minimum of 1.5L a day) to be effective,
and this fluid intake should be specified to be in the form of
non-caffeinated and non-alcoholic beverages.
Regular exercise is generally recommended in the management of constipation, although there is little formal evidence in the literature to support it. This suggestion stems
from the link between constipation and sedentary lifestyles in
epidemiological studies.
Apart from exercise, other simple measures include encouraging patients to adhere to regular meal times (in particular,
to avoid missing breakfast), and to attempt a bowel movement in the morning after breakfast and within the first two
hours of waking (to take advantage of the gastrocolonic
response).
Medical therapy
Laxatives form the mainstay of therapy when simple measures targeting diet and lifestyle factors fail. Table 4 lists
agents commonly used.
Stool softeners
Patients commonly use over-the-counter stool softeners such
as Coloxyl (docusate sodium) although there is little evidence for their use in isolation (level III evidence). The recommended dosage is 1-2 tablets once or twice daily.
They can be useful in improving stool form to a better
consistency that is easier to evacuate. They are also useful as
adjunctive therapy in patients with complications such as
anal fissure (see Specialist intervention and the GP’s ongoing
role, page 38), when keeping the stool form soft helps minimise trauma to the anal canal.
Stimulant laxatives
The level of evidence for stimulant laxatives is comparable to
that for stool softeners. Stimulant laxatives in common use
include conjugated anthraquinone derivatives such as senna
(sennosides A and B) as well as other agents such as bisacodyl
(Bisalax, Dulcolax), and Normacol (a formulation containing
both fibre [sterculia] and a peristaltic stimulant [frangula
bark]).
Stimulant laxatives increase intestinal fluid accumulation
when they are metabolised to an active state by bowel flora
(conjugated anthraquinone derivatives in particular are
cleaved to an active unconjugated state by colonic bacteria),
and may also stimulate sensory nerve endings in the colonic
mucosal lining. Hence they have both secretagogue and prokinetic effects in the colon.
Chronic use of senna-based laxatives can lead to pigmentation of the colonic mucosal lining (melanosis coli).
Melanosis coli in itself is a harmless and somewhat reversible
condition.
However, ongoing use of these agents may lead to tolerance and dependency in the long term, and possibly the condition ‘cathartic colon’ (a rarely seen but severe manifestation
of prolonged laxative use characterised by dilation of the
large bowel).
Hence, regular chronic use of stimulant laxatives is generally discouraged, although they can be useful and cost-effective in the short term. Stimulant laxatives may be especially
useful in some older patients, especially if osmotic agents
lead to loose stools and hence faecal seepage or incontinence.
Osmotic laxatives
Use of osmotic laxatives is supported by stronger evidence in
the literature. These agents include lactulose and sorbitol
(level II evidence) and polyethylene glycol (level I evidence).
36
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Table 3: NHMRC guidelines for a healthy diet*
Food Groups
Men
Cereals
4-12†
Women
4-9
4-6
Vegetables
5
5
5-6
Fruit
2
2
4
Dairy products
2
2
2
Lean meat, poultry,
fish, nuts, legumes
1
1
1.5
Water
>1.5L
>1.5L
>1.5L
‡
Pregnancy
*Number of serves of each food group per day for healthy adults
†
4-9 serves for men > 60 years old; 6-12 serves for men 19-60 years old
‡
4-7 serves for women > 60 years old; 4-9 serves for women 19-60
years old
Table 4: Laxatives in common use
Group
Examples
Stool softeners
Docusate
Stimulants
Senna, bisacodyl, frangula bark
Osmotic agents
Lactulose, sorbitol, polyethylene
glycol, magnesium salts
Suppositories
Glycerine, bisacodyl
Enemas
Sodium citrate with sorbitol,
sodium phosphate
Other osmolar laxatives in
common use include lowdose polyethylene glycol
with electrolytes (Movicol)
and
magnesium-based
agents such as Epsom salts.
Both sorbitol and lactulose are non-absorbable
sugars that are degraded by
colonic bacteria to acidic
molecules that increase the
acidity and osmolarity of
stool, leading to increased
fluid in the colon. The
increased intraluminal bulk
also helps stimulate peristalsis.
Polyethylene glycol is a
potent hyperosmolar agent
that moves a large amount
of fluid into the bowel
lumen. Magnesium salts also
draw fluid into the intestine
and may also hasten transit
time via an increase in cholecystokinin levels.
The usual dosage for the
unabsorbed mono- and disaccharides such as lactulose
and sorbitol is 10-20mL 1-3
times daily. The standard
dosage for magnesium sulphate is 1-2 teaspoons once or
twice daily, and for Movicol
one sachet 1-3 times daily.
Some caution should be
given to use of all osmotic
agents, as they can lead to a
net osmotic influx of water
into the intestines, and hence
dehydration and electrolyte
imbalance.
Occasionally osmotic
bowel preparations such as
large-volume polyethylene
glycol (up to 3L) and Picoprep are used for cases of
severe constipation but they
should be used with extreme
caution (especially Picoprep),
as these particular agents can
cause significant dehydration
and electrolyte disturbance.
These agents should not
be used at all for management of constipation in the
elderly or in patients with
renal impairment. Higher
doses of Movicol (eight
sachets dissolved in 1L of
water a day) have been used
Figure 3: Management of constipation.
Stage 1: Practical management tips
■
Exclude organic pathology or contributory medications. Consider colonoscopy if age > 40
and recent onset of symptoms
■
Increase fluid intake (non-caffeinated, non-alcoholic)
■
Increase in dietary fibre intake (up to 30g/day)
■
Fibre supplementation, eg, psyllium husk, sterculia
■
Incorporate regular exercise into daily routine
■
Address depression or stress issues, if present
■
Encourage regular meals and sleeping patterns (eg, avoid missing breakfast)
■
Advice on correct toilet positioning (eg, use of a footstool)
■
Finally, consider use of laxatives (see Stage 2)
■
The best evidence is for use of osmotic laxatives, eg, low-dose polyethylene glycol
■
Stool softeners are a useful adjunct in patients with hard stool
■
Stimulant laxatives can be used in the short term, especially in older patients
■
Enemas or suppositories, depending on distribution of faecal loading
■
If response is poor, consider referral (see Stage 3)
Stage 2: Pharmacological therapy
Stage 3: Resistant cases
Specialist involvement should be considered at this stage
Suspected pelvic
floor dyssynergia
Suspected colonic
inertia
Anorectal manometry Nuclear medicine
and consideration for colonic transit study,
biofeedback therapy followed by adjustment
of laxatives; may
consider colectomy or
sacral nerve stimulation
Reconsider
organic disease
Suspected
psychological
factors
See table 2 for review
of potential causes
and reconsider
colonoscopy if not
yet done (even if
patient’s age is <40)
Consider
psychological
treatments, eg,
hypnotherapy in
irritable bowel
syndrome
in severe constipation with
faecal impaction.
Lubricants
Paraffin oil has been used for
some time to treat constipation but has several adverse
effects such as lipoid pneumonia from aspiration, granulomatous hepatitis from systemic
absorption, and fat-soluble vitamin deficiencies.
Prokinetic agents
Cisapride increases GI
motor activity and has been
used to treat constipation as
well as other motility disorders such as gastroparesis.
Its use has now been
severely limited because of
associations with cardiac
arrhythmias.
Enemas and suppositories
In patients with faecal loading on abdominal X-ray, or
when physical examination
indicates rectal retention of
stool, local suppositories or
enemas may be helpful.
Enemas provide bulk and
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volume in the rectum, to
stimulate defaecation.
Phosphate-based enemas
such as Fleet are effective
but should be used with
caution in patients prone to
renal or electrolyte problems. Rectal mucosal
damage can occur with
enemas but is uncommon.
Microlax enemas and glycerine suppositories have a
more gentle local effect,
acting as stool softeners in
the rectum, and glycerine as
a 3g suppository also has a
local osmotic effect.
Bisacodyl suppositories
have a stimulant effect on
large-bowel mucosa, which
manifests itself within 1560 minutes of administration.
In cases of severe
impaction, manual removal
is
very
occasionally
required, but this is often
painful and may require
some local anaesthetic gel
or even sedation or anaesthesia.
Combination therapy
Many patients require a
combination of therapies.
For example, patients can
benefit from combining
both non-pharmacological
and pharmacological treatments. Sometimes combinations of laxatives from different classes are also
helpful, for example, using
a stool softener with an
osmotic agent, or using
enemas or suppositories on
an as-needed basis.
To aid compliance, it is
also helpful to provide
patients with a written list
of the dietary, lifestyle and
pharmacological interventions recommended, as
shown in figure 3.
Herbal laxatives
Herbal laxatives may contain a combination of fibre
(eg, psyllium husk), stimulant laxatives (eg, frangula
bark, senna and liquorice),
or osmotic agents (eg, magnesium). Patients may be
unaware that they are taking
stimulant laxatives in their
herbal remedies, so use of
such over-the-counter remedies should be discussed
openly with them, especially
as peristaltic stimulants are
not recommended for prolonged use.
Other agents
Serotonergically active drugs
such as tegaserod, a 5hydroxytryptamine 4 partial
agonist, were used until
recently to stimulate peristalsis, leading to improved
gastric emptying and colonic
transit time. Tegaserod was
in particular noted to be
useful not only in patients
with refractory constipation,
but also in those with constipation-predominant IBS,
due to its inhibition of visceral hypersensitivity. However, tegaserod has been
withdrawn from the market
because of cardiac side
effects.
Another group of agents
showing some promise
include chloride-channel
activators
such
as
lubiprostone. Research is
ongoing to find newer, safer
agents to treat constipation.
When to refer
Referral for specialist investigation is suggested when:
■ Colonoscopy is indicated
because of suspicion of colorectal malignancy.
■ Anorectal manometry is
considered because of
symptoms of pelvic floor
inco-ordination that may
be amenable to biofeedback therapy.
■ Structural lesions such as
megacolon or rectocoele
are suspected.
■ Chronic intractable constipation is present, affecting
quality of life.
■ Diet, lifestyle, and laxative
interventions fail, as discussed above.
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How to treat – constipation
Specialist intervention and the GP’s ongoing role
GASTROENTEROLOGISTS or
colorectal surgeons will consider
whether further investigations such
as colonoscopy are required and
will review the patient’s progress
and treatments to date. In some
cases, formulation of a new management plan may be helpful, but
more specialised interventions
include surgery and biofeedback
therapy.
Indications for surgery
Anal fissures commonly coexist
with constipation and will often
manifest with intense anal pain on
defaecation. Management of constipation will help, but additional therapy with topical nitrates (Rectogesic) may be needed to alleviate
pain. Persistent anal fissures can be
dealt with by injection of botulinum
toxin or by surgical intervention,
with division of the anal sphincter.
In patients with rectocoeles, the
indications to proceed with surgery
are unclear, as alleviation of symptoms does not seem to depend on
the size of the rectocoele. Women
with rectocoeles should be asked if
digital pressure on the posterior wall
of the vagina during defaecation
helps with the passage of stool (in
such cases, the rectocoele functions
as a redundant reservoir of stool,
and surgical removal should
improve the defaecation process).
Patients with rectocoeles should
also be assessed for pelvic floor
dyssynergia, as otherwise symptoms
of defaecatory dysfunction may
recur despite surgery.
Subtotal colectomy for severe
slow-transit constipation (colonic
inertia) is sometimes performed, but
only after all other options have
been explored. Caution is needed if
the patient has significant pain or
upper gut dysmotility, as in these
cases the response to surgery may
be less favourable.
Complications of subtotal colectomy with ileorectal anastomosis
include small-bowel obstruction in
more than one-third of patients, as
well as diarrhoea, incontinence and
even recurrence of constipation
(especially if small-bowel motility is
abnormal).
Another therapeutic option for
colonic inertia, sacral nerve stimulation (already in use for the treatment of faecal incontinence), is currently being performed on a trial
basis.
Biofeedback therapy
In patients with obstructed defaecation resulting from manometryproven pelvic floor inco-ordination,
referral for biofeedback therapy is
strongly supported in the literature
(level I evidence).
Biofeedback therapy has been
shown to have a mean success rate
of 78% in studies for functional
constipation and pelvic floor
dyssynergia, and is currently being
investigated in certain patients with
constipation-predominant IBS. A
typical biofeedback program within
a motility unit at a tertiary referral
centre involves:
■ Weekly clinical interviews (eg,
over six weeks).
■ Education and dietary advice.
■ Medication adjustments, as appropriate.
■ Advice on correct toileting behaviour and positioning.
■ Abdominal breathing technique.
■ Manometry-based biofeedback to
allow anal relaxation and achieve
adequate rectal pressure on strain.
■ Rectal sensory retraining.
■ Balloon expulsion retraining.
After the biofeedback program,
the GP has a crucial role in following up the patient’s symptoms and
encouraging adherence to recommendations provided from the program, to achieve lasting improvement in bowel habit and anorectal
function.
Furthermore, referral to a psychiatrist or psychologist may be helpful
for management of coexistent anxiety or depression, and hypnotherapy or cognitive behaviour programs are used in some patients
with IBS.
Conclusion
Constipation is a common
problem that can significantly
affect the individual’s quality of
life. It is mandatory to exclude
organic conditions such as
colorectal cancer in patients
with a change in their
symptom pattern or other
warning signs.
In most instances patients
respond to simple
management measures, but an
increasing range of options is
available for management in
general practice, with more
specialised interventions in
severe cases.
Reference
1. Mertz H, et al. Physiology of
refractory chronic constipation.
American Journal of
Gastroenterology 1999; 94:
609-15.
Online resources
■
■
■
Gastroenterological Society of
Australia patient leaflet:
www.gesa.org.au/leaflets/
constipation.cfm
National Digestive Diseases
Information Clearinghouse
(patient information):
http://digestive.niddk.nih.
gov/ddiseases/pubs/
constipation
MJA Practice Essentials –
Paediatrics. 5. Constipation
and toileting issues in
children:
http://mja.com.au/public/issues
/182_05_070305/cat10379_
m.html
PLEASE REVIEW PRODUCT INFORMATION BEFORE PRESCRIBING. PRODUCT INFORMATION CAN BE FOUND IN THE PRIMARY ADVERTISEMENT IN THIS PUBLICATION.
PBS Information: Restricted benefit. For single maintenance and reliever therapy in a patient who experiences frequent asthma
symptoms while receiving treatment with oral corticosteroids or inhaled corticosteroids or a combination of an inhaled corticosteroid and a long
acting beta-2-agonist (Symbicort 400/12 is not recommended nor PBS subsidised for use in maintenance and reliever therapy).
38
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AD_039___SEPT19_08 Page 6 11/9/08 3:28 PM
Authors’ case studies
Constipation with
overflow diarrhoea and
incontinence
A 56-YEAR-old woman was
admitted to hospital with a
five-month history of diarrhoea with faecal incontinence.
She described sudden onset of
diarrhoea, initially occurring
10 times a day and up to 25
times a day at its maximum,
with associated faecal incontinence.
Her background medical
history included rheumatoid
arthritis and osteoporosis, and
a strong family history of colorectal cancer. Her medications included Imodium two
tablets three times a day, psyllium husks one teaspoon daily,
prednisone 15mg daily, sulfasalazine, hydroxychloroquine, alendronate, paracetamol, ranitidine, vitamin D,
Caltrate, glucosamine and fish
oil. None of these medications
had been started around the
onset of the diarrhoea.
The patient underwent a
series of investigations, including stool cultures with
Clostridium difficile toxin;
blood tests, including thyroid
function, coeliac serology,
serum gastrin and vasoactive
intestinal peptide levels; as well
Figure 4. Left: Pre-treatment abdominal X-ray with faecal loading. Right: Post-treatment X-ray
showing clearance of faecal loading.
as colonoscopy with random
colonic biopsies, with no cause
for diarrhoea found.
She was prescribed courses
of metronidazole and tinidazole, in case of undetected protozoal infection, but these
made no impact on her diarrhoea. She also underwent a
small-bowel series, which
showed prolonged transit, and
anorectal manometry, which
showed low anal squeeze pressures and rectal hyposensitiv-
ity. A subsequent abdominal
X-ray revealed extensive faecal
loading (figure 4).
A diagnosis of constipation
with overflow diarrhoea and
incontinence was made, and
the patient was treated with
regular Movicol (one sachet
bd) and Epsom salts (one
teaspoon bd), with a short
course of Coloxyl with
Senna and Fleet enemas
daily to clean out the bowel.
She was also advised to stop
Imodium and increase her
intake of fluids to 3L a day.
She subsequently underwent a course of anorectal
biofeedback therapy for the
symptom of incontinence, to
increase her anal sphincter
squeeze pressures and improve
rectal sensitivity. She noted a
significant improvement in her
bowel habit within a few
weeks and has maintained regular bowel movements twice
daily.
Constipation-predominant
IBS
A 47-year-old man presented
with a 20-year history of
severe constipation associated
with abdominal pain and
bloating, which had begun
after a bout of infective gastroenteritis. He described
difficulty with defaecation,
feeling as though his anal
passage was “shut down”,
excessive straining, and
excessive time spent on the
toilet.
His toileting routine occupied 7-8 hours a day and he
had developed a dependence
on a modified squat-toilet
system that he had set up at
home, which was a major
imposition on his quality of
life. He had not travelled
away from home in 20
years, given this need to use
his own toilet system.
Over the preceding 10
years, he had sought multiple medical opinions, and a
colonic transit study had
shown slow transit, and a
defaecating proctogram had
shown extremely poor emptying.
Because of predominant
symptoms of constipation
with sensations of anal
blockage and incomplete
emptying, he was referred
for anorectal manometry.
This revealed elevated resting anal sphincter pressure
and rectal hypersensitivity,
as well as extremely high
rectal pressure on strain,
with paradoxical anal contraction on strain. The findings were consistent with his
clinical diagnosis of constipation-predominant IBS
(probably post-infective)
with concurrent pelvic-floor
dyssynergia.
The patient underwent a
six-visit course of biofeedback
therapy, including the following components:
■ Advice on correct toileting
position and behaviour.
■ Improvement in fibre and
water intake.
■ Abdominal breathing technique.
■ Manometry-based therapy
to allow anal relaxation
with strain.
After treatment he noted a
significant improvement in his
bowel habit and abdominal
bloating. In particular, he had
reduced his toileting time to
three hours a day and had
even managed a short holiday away from home.
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References: 1. Kuna P et al. Int J Clin Prac, 2007; 61(5): 725–736. 2. Bousquet J et al. Respir Med, 2007; 101: 2437–2446. 3. Vogelmeier C et al. Eur Respir J, 2005; 26: 819–828. 4. Symbicort Approved Product Information,
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39
AD_ 0 4 0 _ _ _ SEPT 1 9 _ 0 8 . PDF
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How to treat – constipation
GP’s contribution
Case study
DR MATILDA METLEDGE
Sydney, NSW
MR B, 35, underwent
major back surgery four
months ago. During his
hospital stay he was
required to lie flat for three
days and developed severe
constipation with intense
abdominal pain. He was
finally (after another two
days) treated with an
enema, with good result.
Since discharge he has
never returned to his
normal bowel habit of
every 1-2 days (now every
3-6 days) and feels constantly bloated and full. His
abdominal X-ray showed
faecal loading, and a repeat
enema was given a few
weeks ago, again with good
effect.
He remains on low-dose
Endone (5mg daily) along
with four Coloxyl with
Senna bd, which he states
“does nothing”. He now
returns with the same
bloating and fullness.
Questions for the authors
For patients on long-term
opiates for chronic pain,
what would your advice be
in regard to pharmacological therapy for constipation?
If patients are taking opiates for the long term, and
need treatment for constipation other than correction of
fibre and water intake, often
an osmotic agent will be
required, as these are effective
and the dose can be titrated.
How to Treat Quiz
Constipation — 19 September 2008
1. Which TWO statements about the
epidemiology of constipation are correct?
a) The prevalence of constipation in the
general population is 15-20%
b) In patients under 50, men are twice as
likely to be affected as women
c) Groups more likely to be affected by
constipation include the elderly, children
and pregnant women
d) A NSW survey showed most patients with
constipation sought help for their
condition
2. Which TWO statements about causes of
constipation are correct?
a) It is very important to consider mechanical
obstruction from colorectal malignancy as a
cause of constipation
b) Metabolic disorders that may be associated
with constipation include diabetes mellitus
and hypercalcaemia
c) There are no diagnostic criteria for
functional constipation; rather, this is a
diagnosis of exclusion
d) Pelvic floor dyssynergia causes urinary
difficulties but not constipation
3. Kim, 38, has suffered from constipation
since her early teens but has not sought
help in managing it before. Which THREE
statements about assessing patients with
constipation are correct?
a) A careful review of medication needs to be
undertaken, including over-the-counter
agents such as calcium and iron
supplements
b) History should include enquiry about
symptoms that may indicate pelvic floor
dysfunction
c) Enquiring about a family history of bowel
disorders is not important in the history
d) Digital rectal examination is an essential
component of the physical examination
4. You take a full history from Kim. Dietary
history reveals a low-fibre diet. She has no
warning symptoms for malignancy, and the
relevant physical examination is normal.
Which TWO statements about investigating
constipation are correct?
a) Initial blood tests may include FBC, serum
calcium, blood glucose level and thyroid
function testing
b) There is no role for a plain abdominal X-ray
in patients with constipation
c) A colonoscopy should be considered in all
patients with warning signs for malignancy
d) There is no role for a barium enema in
patients with constipation
5. Which TWO statements about additional
investigations are correct?
a) Defaecography can be useful for detecting a
rectocoele with stool retention
b) Patients unable to expel the balloon on a
balloon expulsion test within 15 seconds
are highly likely to have pelvic floor
dyssynergia
c) A nuclear medicine colonic transit study is
normal if there is significant residual tracer
by day 5
d) Hirschsprung’s disease can be largely
excluded by anorectal manometry
Some caution needs to be
given about long-term stimulant laxatives, as discussed
earlier (page 36). If stools
remain hard despite correction of fluid and fibre
intake, a stool softener can
be added in.
What dose of Coloxyl is
reasonable to commence
with in this type of case,
and how high can the dose
be titrated before we can
state treatment failure?
Coloxyl (without senna)
is merely a stool softener
and its efficacy is mild. I
usually prefer to optimise
the stool form with water
and fibre first, but if I do
use Coloxyl I don’t go
above two or three tablets
twice daily.
Most patients require
much encouragement to
achieve even the NHMRC
guidelines for water and
fibre intake for the normal
individual. If using Coloxyl
with Senna in the short
term, I usually don’t go
above two tablets twice
daily.
Is it best to use multiple
agents in low doses or to
escalate a single drug to the
maximum dose in resistant
uncomplicated constipation?
I do not see the point in
using more than one agent
from the same class of laxatives. However, I sometimes
use combination therapy
with, say, an osmotic
agent, supplemental fibre
and prn enemas, suppositories or possibly stimulant laxatives. In all
situations I attempt to
normalise the form of the
stool.
General question for the
authors
Could you extrapolate on
‘correct toileting behaviour
and positioning’, besides
footstools and morning
attempts?
Some patients have quite
abnormal toileting behaviours and we try to modify
this. For example some
patients spend more than
30 minutes per attempt at
toileting, some are making
multiple attempts to defaecate per day, some have
excess straining, some
attempt to defaecate standing or sit in a very contorted position and some
patients are digitally
disimpacting.
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by post or fax.
The mark required to obtain points is 80%. Please note that some questions have more than one correct
answer.
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6. You arrange for Kim to have some
initial blood tests, the results of which
are normal. You also discuss the
current recommendations for fibre intake
with her. Which TWO statements are
correct?
a) NHMRC guidelines recommend intake of
15g of fibre a day for women, and 20g a
day for men
b) NHMRC recommendations are two serves
of fruit and five serves of vegetables daily
c) NHMRC recommendations for daily intake
of cereal products are 2-4 serves for men
and 2-3 serves for women
d) Fibre intake should be combined with a
minimum of 1.5L of non-caffeinated and
non-alcoholic fluids a day
7. You also discuss with Kim the use of a
fibre supplement, such as psyllium. Which
THREE statements about the management
of constipation are correct?
a) The benefits of supplemental fibre will be
evident to the patient within 1-2 days
b) Regular exercise is generally recommended
in the management of constipation
c) Symptoms of anxiety or depression should
be addressed if present
d) Patients should be encouraged to avoid
missing breakfast
8. Kim reveals that she occasionally takes
Coloxyl with Senna when her constipation
is particularly troublesome. Which TWO
statements are correct?
a) There is good evidence (level I) to support
the use of stool softeners
b) Regular chronic use of stimulant laxatives is
generally discouraged in young patients
c) Stimulant laxatives can be used in the short
term, especially in older patients
d) There is no benefit from combining laxatives
from different classes
9. Which TWO statements about
pharmacological therapy for constipation
are correct?
a) There is little evidence to support the use of
osmotic laxatives
b) Some caution should be given to use of all
osmotic agents, as they can lead to
dehydration and electrolyte imbalance
c) Paraffin oil has a benign side-effect profile
d) Phosphate-based enemas should be used
with caution in patients prone to renal or
electrolyte problems
10. Which THREE statements about
specialist management of constipation are
correct?
a) In patients with rectocoeles there are clear
indications as to when to proceed with
surgery
b) Subtotal colectomy for severe slow-transit
constipation is sometimes performed, but
only after all other options have been
explored
c) There is good evidence to support
biofeedback therapy for patients with
obstructed defaecation due to manometryproven pelvic floor inco-ordination
d) If there are suspected psychological factors,
referral to a psychiatrist or psychologist may
be helpful
CPD QUIZ UPDATE
The RACGP now requires that a brief GP evaluation form be completed with every quiz to obtain category 2 CPD or PDP points for the 2008-10 triennium. You
can complete this online along with the quiz at www.australiandoctor.com.au. Because this is a requirement, we are no longer able to accept the quiz by post
or fax. However, we have included the quiz questions here for those who like to prepare the answers before completing the quiz online.
HOW TO TREAT Editor: Dr Wendy Morgan
Co-ordinator: Julian McAllan
Quiz: Dr Wendy Morgan
NEXT WEEK Panic attacks visit with a shocking suddenness, alarming severity and terrifying portent. The next How to Treat will help explain what causes panic attacks to persist — one of the most
important factors in understanding how to treat them. The author is Dr Lisa A Lampe, senior lecturer, discipline of psychological medicine, University of Sydney; consultant psychiatrist, CADE clinic, Royal
North Shore Hospital, St Leonards; and senior staff specialist (academic), Hornsby Ku-ring-gai Health Service, Hornsby, NSW.
40
| Australian Doctor | 19 September 2008
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