Constipation Flashcards
(31 cards)
How do you define constipation
- defined as the passage of less than or equal to 2 bowel motions a week often passed with difficulty, straining or pain and a sense of incomplete evacuation
What could it mean if you have constipation and rectal bleeding
- cancer
What could it mean if you have constipation, distension and active bowel sounds
- stricture
- GI obstruction
what could it mean if you have constipation and menorrhagia
- hypothyroidism
Name the major causes of constipation
- general
- anorectal disease
- intestinal obstruction
- metabolic/endocrine
- drugs
- neuromuscular (slow transit from decreased propulsive activity)
What are the general causes of constipation
- poor diet +- lack of exercise
- poor fluid intake/dehydration
- IBS
- old age
- post-operative pain
- hospital environment (lack of privacy, having to use a bed pan)
What are the intestinal obstruction causes of constipation
- colorectal carcinoma
- strictures - e.g. Crohn’s
- pelvic mass - e.g. foetus, fibroids
- diverticulosis (PR bleeding more common presentation)
- pseudo-obstruction
What are the drug causes of constipation
- opiates - morphine, codeine
- anticholinergics e.g. TCAs
- iron
- some antacids - with aluminium
- diuretics - e.g. furosemide
- CCBs
What are the anorectal disease causes of constipation
- anal or colorectal cancers
- fissures, strictures, herpes
- rectal prolapse
- proctalgia fugax
- mucosal ulceration/neoplasia
- pelvic muscle dysfunction/levator ani syndrome
What are the endocrine causes of constipation
- hypercalcaemia
- hypothyroidism
- hypokalaemia
- porphyria
- lead poisoning
What are the neuromuscular causes of constipation
- spinal or pelvic nerve injury - e.g. trauma, surgery
- aganglionosis - chugs disease, hirschprung’s disease
- systemic sclerosis
- diabetic neuropathy
What are the other causes of constipation
- chronic laxative abuse
- idiopathic slow transit
- idiopathic megarectum/colon
What should you ask for history in constipation
- Nature, frequency and consistency of stools
- Blood or mucus in stools
- Diarrhoea alternating with constipation (eg IBS)
- Recent change in bowel habit
- Digitating rectum (or vagina in rectocele) to pass stools
- Ask about diet and drugs
→ DRE essential even when referring (refer if signs of colorectal ca, eg weight loss, pain or anaemia)
When do you investigation constipation
- non in young, mild affected patients
- threshold for investigation diminishes with age - triggers include: weight loss, abdominal pain, PR blood, iron deficiency, anaemia
What investigations do you use in constipation
- Blood - FBC, ESR, CRP, U&Es, Calcium, TFT
- Colonoscopy - if suspected colorectal malignancy
- other occasionally needed - transit studies, anorectal physiology, biopsy for Hirschprung’s disease
what are the management for constipation
- reassurance, drinking more, diet and exercise advice is all that is needed
- treat causes
- high fibre diet - can lead to bloating and might not help constipation
- only use drugs if these measures fail and use them for short periods only
- often a stimulant such as a Senna, and +- a bulking agent is more effective and cheaper than agents such as lactulose
How does bulking agents work
- this is when you increase in faecal mass so stimulating peristalsis
- this must be taken with plenty of fluids and may take days to act
What are the contraindications of bulking agents
- difficulty in swallowing
- GI obstruction
- colonic atony
- faecal impaction
Name some bulking agents
- Bran powder 3.5 2-3 times/d with food – may hinder absorption of dietary trace elements if taken with every meal
- Ispaghula husk eg 1g Fybogel® sachet after a meal – mixed in water and swallowed promptly
- Methylcellulose eg Celevac® 3-6 tablets/12h with ≥300ml water
- Sterculia eg Normacol® granules 10ml sprinkled on food daily
How do stimulant laxatives work
increased intestinal mobility so do not use in intestinal obstruction or acute colitis
Why should you avoid the use of stimulant laxatives
- avoid prolonged use as it may cause colonic atony
What are the side effects of stimulant laxatives
- abdominal cramps
Name some examples of stimulant laxatives
- Bisacodyl tablets (5-10mg at night) or suppositories (10mg in morning)
- Senna (2-4 tablets at night)
- Docusate sodium and Dantron – have stimulant and softening action
- Glycerol suppositories – act as rectal stimulant
- Sodium picosulfate (5-10mg at night) – potent stimulant
when are stool softeners useful
- when managing painful anal conditions such as fissure
