Constipation Flashcards
What is constipation?
symptom-based disorder which describes defectation that is unsatisfactory because of infrequent stools, difficulty passing stools, or the sensation of incomplete emptying
What diagnostic criteria exists for constipation and what does this define as constipation?
- Rome IV diagnostic criteria for constipation
- includes spontaneous bowel movements occuring <3 times a week
What is the character of the stool in constipation?
- dry, hard or lumpy, may be abnormally large or small
- passage of stools less frequently than the person’s normal pattern (= diagnosis in reality)
What is meant by chronic constipation?
symptoms which are present for at least 12 weeks in the preceding 6 months
What is meant by ‘faecal loading’/impaction?
retention of faeces to the extent that spontaneous evacuation is unlikely
What is overflow faecal incontinence?
leakage of liquid stool from the proximal colon around impacted faeces, where small quantities of stool may be passed frequently and without sensation
What is functional (aka primary or idiopathic) constipation?
chronic constipation without a known cause
What are 3 physiologic subtypes of functional constipation?
- Normal transit: constipation with no time delay in passage of stool through colon
- Slow transit: prolonged delay in passage of stool through colon
- Outlet delay (or obstructed defecation): can be caused by pelvic floor dyssynergia - uncoordinated, contract rather than relax during atempted defecation
What is the most common type of functional constipation?
normal transit
What is secondary (organic) constipation?
caused by medication or underlying medical condition
What are 3 groups of risk factors for developing constipation?
- Social (diet, exercise, limited privacy)
- Psychological (anxiety, depression)
- Physical (female, age, dehydration)
What are 4 examples of social risk factors for developing constipation?
- Low fibre diet or low calorie intake
- Difficult access to toilet, or changes in normal routine or lifestyle
- Lack of exercise or reduced mobility
- Limited privacy when using the toilet
What are 4 examples of psychological risk factors for constipation?
- Anxiety and/or depression
- Somatisation disorders
- Eating disorders
- History of sexual abuse
What are 4 physical risk factors for constipation?
- Female sex
- Older age
- Pyrexia, dehydration, immobility
- Sitting position on a toilet seat compared with squatting position for defecation
What are 10 examples of drug causes that can cause secondary constipation?
- Aluminium-containing antacids
- Iron or calcium supplements
- Analgesics e.g. opiates, NSAIDs
- Antimuscarinics e.g. procyclidine, oxybutynin
- Antidepressants, such as TCAs, antipsychotics e.g. clozapine
- Antiepilptics e.g. carbamazepine, gabapentin, pregabalin, phenytoin
- Antihistamines
- Antispasmodics e.g. dicycloverine or hyoscine (anti-muscarinic type)
- Diuretics e.g. furosemide
- CCBs e.g verapamil
What are 5 groups of organic causes of constipation?
- Endocrine and metabolic diseases
- Myopathic conditions
- Neurological conditions
- Structural abnormalities
- IBS, slow transit constipation, pelvic or anal dyssynergia
What are 7 endocrine and metabolic diseases that can cause constipation?
- Diabetes mellitus (with autonomic neuropathy)
- Hypercalcaemia and hyperparathyroidism
- Hypermagnesaemia
- Hypokalaemia
- Hypokalaemia
- Hypothyroidism
- Uraemia
What are 3 myopathic conditions which can cause constipation?
- Amyloidoss
- Myotonic dystrophy
- Scleroderma
What are 6 neurological conditions which can cause constipation?
- Autonomic neuropathy
- Cerebrovascular disease
- Hirschprung’s disease
- Multiple sclerosis
- Parkinson’s disease
- Spinal cord injury, tumours
What are 6 structural abnormalities that can cause constipation?
- Anal fissures, strictures, haemorrhoids
- Colonic strictures (e.g. following diverticulitis, ischaemic, surgery)
- Inflammatory bowel disease
- Obstructive colonic mass lesions e.g. due to colorectal cancer
- Rectal prolapse or rectocele
- Postnatal damage to the pelvic floor or third degree tear
What are 3 complicatios of chronic constipation?
- Haemorrhoids or anal fissure
- Progressive faecal retention, distension of the rectum, loss of sensory and motor function
- Faecal loading and impaction
What are 6 complications of chronic faecal loading and impaction?
- Faecal incontinence, which can be embarrassing and distressing
- Chronic dilatation of the colon may cause megacolon
- Bowel obstruction, perforation or ulceration
- Recurrent UTIs, obstructive uropathy
- Rectal bleeding
- Rectal prolapse
What are 4 things that should make you suspect a diagnosis of constipation?
- Bowel movements <3x a week
- Daily bowel movements but associated symptoms such as excessive straining
- Additional symptoms may include lower abdominal pain or discomfort, distension, or bloating
- Less frequent passage of stools compared with normal pattern
What are 4 possible symptoms of constipation in the elderly?
- Confusion or delirium, functional decline
- Nausea or loss of appetite
- Overflow diarrhoea
- Urinary retention
What are 3 things that should make you suspect a diagnosis of faecal loading or impaction?
- Hard, lumpy stools, which may be large and inferquent (e.g. every 7-10 days) or small and relatively frequent (every 2-3 days)
- Having to use manual methods to extract faeces
- Overflow faecal incontinence, or loose stool
What are 10 aspects of the assessment of a patient with suspected constipation?
- Ask about red flag symptoms e.g. suggesting colorectal cancer
- Ask about normal pattern of defecation
- Symptoms of constipation
- Fever, nausea, vomiting, loss of appetite and/or weight
- Urinary symptoms
- FH of colorectal cancer or infalmmatory bowel disease
- Impact on QoL
- Any measures tried
- Ask quetsions about faecal loading
- Examination with informed consent
What are 4 symptoms of faecael loading and/or impaction to ask about?
- History of faecal incontinence e.g. underwear regularly soiled
- Excessive wiping
- Loose stools
- Whether person has needed to use manual measures to relieve constipatoin
What are 4 examples of manual methods to relieve constipation?
- A finger having to be inserted into the vagina suggests a rectocele.
- A finger in the rectum to push away a flap suggests a rectal ulcer.
- Pressure behind the anus may assist defecation if the levator muscles are weak.
- Digital rectal evacuation of faeces confirms severe faecal loading and/or impaction.
What are 7 aspects of an examination in a person with constipation?
- Signs of weight loss and nutritional health status
- Abdominal examination: pain, distension, masses, palpable colon
- Internal rectal examination for fissures, haemorrhoids, skin tags, rectal prolapse, rectocele, skin erythema or excoriation (may be sign of faecal leakage)
- Resting anal sphincter tone, rectal mass leions, retains faecal masses
- Pelvic floor dysfunction - ask person to ear down, may be paradoxical contraction of anal sphincter on strianing
- Leakage of stool
- Rectal or anal pain
What are 5 aspects of lifestyle advice to give in constipation?
- Sources of information and support e.g. NHS PIL on Constipation and Bowel Incontinence
- Eating a healthy, balanced diet and having regular meals
- Drinking an adequat fluid intake, especially if there is a risk of dehydration
- Increasing activity and exercise levels if needed
- Helpful toileting routines
What are 4 aspects of eating a balanced, healthy diet that you should advise for constipation?
- Whole grains
- Fruits high in sorbitol e.g. apples, apricots, grapes, peaches, pears, plums, raspberries, strawberries
- Vegetables
- Fibre intake should be gradually increased, aim for 30g a day
What are 4 types of advice on helpful toileting routines you can give?
- Advise on regular, unhurried toilet routine, giving time to ensure defecation complete
- Advise on responding immediately to sensation of needing to defecate
- Ensure people with limited mobility have appropriate help to access toilet and adequate privacy
- Ensure person has access to supported seating if they are unsteady on the toilet
What are 6 aspects of the management of short-duration constipation?
- Manage any underlying secondary cause, stop drug treatment that can contribute
- Lifestyle measures
- Offer treatment with oral laxatives using stepped approach if other methods haven’t worked
- If opioid induced constipation, don’t prescribe bulk-forming laxatives, offer osmotic + stimulant laxative
- Advise to gradually reduce and stop laxatives once producing soft, formed stool without srtaining at least 3x a week
- Arrange to review person regularly, depending on clinical judgement
What are 4 aspects of the stepped approach to treating short-duration constipation with laxatives?
- Bulk forming laxative first-line e.g. ispaghula
- Then add or switch to osmotic laxative e.g. a macrogol
- If macrogol ineffective or not tolerated, offer treatment with lactulose second line
- If stools soft but difficult to pass/inadequate emptying, add stimulant
What is the management of opioid-induced constipation?
- do NOT prescribe bulk-forming laxatives
- offer an osmotic laxtive and stimulant laxative (or docusate - stool-softening properties)
What are 7 aspects of the management of chronic constipation?
- Manage any underlying secondary cause/drugs causing
- Advise on lifestyle measures
- Manage any faecal loading/impaction first, if present
- If ongoing symptoms, offer drug treatment with laxatives stepped approach
- consider treatment with prucalopride if at least 2 laxatives from different classes have been tried at highest doses for at least 6 months
- Gradually titrate doses up or down aiming for soft, formed stool without straining at least 3x a wek
- Arrange to review regularly
What is the stepped approach with oral laxatives for chronic constipation?
same as for short-duration
What is prucalopride? How does it work?
prokinetic: selective, high affinity, serotonin receptor agonist
stimulates gastrointestinal motility
What course of treatment is given when prucalopride is indicated?
4 week prescription; if no symptom response, reconsider benefit of continuing treatment
What is the management of faecal impaction/ loading? 6 aspects
- If hard stools, consider prescribing high dose of oral macrogol
- If soft stools or ongoing hard stools after few days treatment with macrogol, consider starting or adding oral stimulant laxative
- If no response, can prescribe
- suppository e.g. bisacodyl for soft stools; glycerol alone, or glycerol plus bisacodyl
- mini enema e.g. docusate or sodium citrate
- If still inadequate, consider sodium phosphate or arachis oil retention enema
- Reinforce lifestyle advice
- Consider need for regular laxative to maintain bowel movements, or intermittent for episode of faecal loading
What should you warn patients about when prescribing enemas?
may need district nurse to help administer
can cause diarrhoea and faecal overflow before disimpaction is complete
What are the 4 steps of management of constipation in pregnancy with laxatives?
- Offer bulk-forming laxative first-line, e.g. ispaghula
- Next add or switch osmotic laxative such as lactulose
- If sitll inadequate, consider short course of stimulant e.g. senna
- if still inadequate, consider glycerol suppository
What are the 4 steps of management of constipation in breastfeeding with laxatives? What are 2 ways that this differs from pregnancy?
- Offer bulk-forming laxative first-line, e.g. ispaghula
- Next add or switch osmotic laxative such as lactulose or macrogol
- If sitll inadequate, consider short course of stimulant e.g. senna or bisacodyl
- if still inadequate, consider glycerol suppository
can use marcrogol/ bisacodyl
How should laxatives be stopped?
do not stopped suddenly, weaning may take several months
should be guided by frequency and consistency of stools
reduce gadually e.g. after 2-4 weeks when regular bowel movements are comfortable
How should you stop laxatives when more than one has been used?
reduce and stop one laxative at a time, starting with stimulant laxatives if possible
may need to adjust doses of other laxatives to maintain regular bowel movements
What should you consider if symptoms are ongoing or refractory to laxative treatment?
- check blood tests - FBC, TFTs, HbA1c serum electrolytes and calcium - for underlying cause
- could it be a defecatory disorder e.g. pelvic floor dyssynergia
What are 3 situations to consider specialist advice for constipation?
- serious underlying cause e.g. colorectal cancer suspected
- underlying secondary cause suspected that can’t be managed in primary care
- symptoms persist or recur despite optimal management in primary care
What are 2 additional services you could consider referring a patient with constipation to, other than gastro/colorectal surgeon?
- local continence service (if available)
- dietitian if needed
What are 7 types of specialist investigations for constipation?
- Flexible sigmoidoscopy
- Colonoscopy
- Computed tomographic colonography
- Abdominal x-ray
- Anorectal manometry
- Defectation proctogram
- Colon transit time studies with radio-opaque markers or wireless capsule to determine which subtype is involve (e.g. slow colonic transit or pelvic floor dyssynergia)
What are 2 types of specialist management of constipation?
- Biofeedback training by physiotherapist for some defecation disorders e.g. pelvic floor dyssynergia
- Surgery e.g. subtotal colectomy with ileorectal anastomosis
How do bulk-forming laxatives work?
retain fluid with the stool and increase faecal mass, stimulating peristalsis; also have stool-softening properties
What are 3 examples of bulk-forming laxatives?
- Isaghula husm
- Methylcellulose
- Sterculia
How do osmotic laxatives work?
increase amount of fluid in the large bowel producing distension, which leads to stimulation of peristalsis. lactulose and macrogols also have stool-softening properties
What are 3 examples of osmotic laxatives?
- Lactulose
- Macrogols (polyethylene glycols)
- Phosphate and sodium citrate enemas
What is the mechanism of action of stimulant laxatives?
cause peristalsis by stimulaing colonic nerves (senna) or colonic and rectal nerves (bisacodyl, sodium picosulfate)
What are 4 examples of stimulant laxatives?
- Senna
- Bisacodyl and sodium picosulfate
- Docusate
What is an example of a prokinetic laxative?
prucalopride
What are 8 situations when you should not prescribe laxatives?
if there’s suspected:
- intestinal obstruction or perforation
- paralytic ileus
- colonic atony or faecal impaction (bulk-forming laxatives don’t prescribe)
- Crohn’s disease or UC
- Toxic megacolon
- Severe dehydration (bisacodyl)
- Galactosaemia (lactulose)
- History of hypersensitivity to peanuts (arachis oil enema)
What might happen if you prescribe lactulose in lactose interolance?
diarrhoea
When should you take caution when prescrbing Movicol?
it’s high in sodium - be careful if on a low salt diet
When should bulk-forming laxatives such as Ispaghula and sterculia be considered first line?
if difficultt o get adequate dietary fibre (better tolerated than bran)
What are 3 examples of macrogols?
- Idrolax
- Movicol-Half
- Movicol
Which laxatives should you be careful of prescribing in cardiovascular disease?
macrogols
What is a common side effect of bulk-forming laxatives?
flatulence and bloating
What are 3 side effects of osmotic laxatives?
- abdo pain or cramps
- blating
- nausea and vomiting
What are 4 side effects of stimulant laxatives?
- abdo cramps
- diarrhoea
- nausea and vomiting
- senna may cause yellowish-brown discolouration of urine
What are 4 side effects of prucalopride?
- Headache
- Nausea
- Diarrhoea
- Abdominal pain
