Constipation in Adults
Definition
Functional constipation is generally defined as a disorder characterized by persistent difficult or
seemingly incomplete defecation and/or infrequent bowel movements (once every 3–4 days or less)
in the absence of alarm symptoms or secondary causes. (World Gastroenterology Organisation
W.G.O. 2010)
Pathophysiology
There are two main reasons for constipation,
1) Disorders of transit e.g. decreased colonic activity
2) Disorders of evacuation- colonic transit may be normal but evacuating stools from the rectum is
inadequate or difficult
Associated conditions and
medications
(Adapted from W.G.O.2010)
Mechanical obstruction Eg. Colorectal
tumour Megacolon
Neurological disorders/neuropathy
Eg. Multiple sclerosis Spinal cord
pathology
Gastrointestinal disorders and local
painful conditions
Eg Irritable bowel syndrome Anal fissure
Haemorrhoids, Rectal prolapse
Endocrine/metabolic conditions
 Chronic kidney disease Dehydration
 Diabetes mellitus
 Hypothyroidism
Myopathy
Eg Scleroderma
Systemic sclerosis
Dietary
Dieting, fluid depletion, Low fibre, Anorexia,
dementia, depression
Miscellaneous
Cardiac disease,
Degenerative joint disease,
Immobility
Prescription Drugs
Factors which increase the risk of constipation
(W.G.O.2010)
Aging (but constipation is not a physiological consequence
of normal aging)
Depression
Inactivity
Low calorie intake
Low income and low education level
Number of medications being taken (independent adverse
effect profiles)
Physical and sexual abuse
Female sex—higher incidence self-reported constipation in
women
Assessment
Assessment is vital to determine the cause of constipation
 Past medical history
 Patients description of symptoms
 Bristol stool scale
 Diet and bowel diary
 Medication
 Physical examination
 Patients lifestyle
 Blood tests if indicated
The Bristol stool scale
The stool consistency is considered a better indicator of
colon transit than stool frequency (WGO 2010)
Eg Antipsychotics opiates
Self medication, over the counter
drugs
Eg Antacids (containing aluminium,
calcium),
Antidiarrheal agents, steroidal antiinflammatory drugs
Alarm symptoms
Change in stool consistency, colour
Blood in stools or rectal bleeding
Anaemia
Weight loss
Possible investigations
Colonoscopy
Anal manometry
Transit studies
Conservative management (once organic causes have been excluded)







Dietary measures - a gradual increase in dietary fibre. Pre & probiotic drinks Note; A
sudden switch can cause abdominal pain, increased flatulence and bowel urgency
Irritable Bowel syndrome- Insoluble fibre is not recommended. Soluble fibre eg oats is
recommended NICE 2008
Maintain an adequate fluid intake 6-8 glasses fluid per day
Allow time to sit to toilet
Behavioural advice
Stop constipating medication if possible
Biofeedback
Adopt the correct seating position
see trust leaflets; Dietary Fibre GHP10810-06-09 Improving bowel function and control
GHP10810-096-09
Oral Medication
Bulk forming laxatives
Osmotics
Stimulants
Softeners
Pro kinetics
eg
eg
eg
eg
eg
Psyllium methyl cellulose
Polyethylene glycol, Lactulose
Bisacodyl/sodium picosulfate Senna
Dioctyl
Prucalopride
see NICE report 2010
http://www.nice.org.uk/nicemedia/live/13284/52078/52078.pdf
Bulk forming laxatives are useful when dietary fibre is inadequate but should be avoided if fluid
intake is poor .
Osmotic laxatives are useful as they draw water into the gut softening the stool without increasing
peristalsis.
Softeners can be useful and are often used in conjunction with a stimulant
Stimulants should not be used as a first line of treatment as they can cause abdominal cramping if
the stool is hard, however are useful in neurological conditions such as multiple sclerosis with
evacuation difficulties.
Prokinetics normalise peristalsis and are recommended for women when other laxatives have failed
and invasive methods are being considered (NICE 2010)
Rectal Medication
can be particularly useful with evacuation disorders. Eg Glycerine suppositories
Rectal stimulation
can be useful in spinal injury but should be used with caution in case of
autonomic dysreflexia (AD) however this can also prevent AD
Anal Irrigation
Can be useful when constipation has not been resolved by conservative
measures or medication.
If you feel a patient would benefit from anal irrigation contact the continence
service for advice
Surgery
when all measures have failed
Only very few patients benefit from a (reversible) colostomy to treat
constipation.(WGO 2010)