2. Constipation and Diarrhoea Flashcards
What is the prevalence of Constipation?
• Prevalence
o Primary care- 20%
o Nursing Homes – 50%
What are some of the complications of Constipation?
- Serious complication is faecal compaction, can lead to faecal overflow and incontinence
- Faecal incontinence and constipation are risk factors for UTIs and pressure ulcers
- Significant association between constipation and physical aggression in NHs
- Can be cause of physical and physiological trauma
- Use of antipsycotics can compound constipation
How do you diagnose constipation?
• Subjective • Frequency • Consistency • Effort required (straining) • Pain • Discomfort ⇨ how often do you have bowel motion? o For people eating “normal western” diets, • Normal number of bowel actions can be anywhere between 2 bowel actions/week to 3 per/day
Describe the Rome III Criteria for Chronic constipation
• Presence of 2 or more of the following
o Straining during at least 25% of bowel movements
o Lumpy or hard stools in at least 25% of bowel movements
o Sensation of anorectal blockage for at least 25% of bowel movements
o Manual manouvres to facilitate at least 25% of bowel movement
o Fewer than 3 bowel movements each week.
• Loose stools are rarely present without laxatives
• These criteria must have been present for the last 3 months, with symptom onset at least 6 months prior to diagnosis
Name some of the causes of constipation
• Low fibre/fluid diet • Not enough exercise • Ignoring the call to go o Lack of privacy o Confined to bed Medications Disease
Name some of the medications that cause consitpation
o Eg. Aluminium and/or calcium antacids
o Iron preparations
o Opioids
o Verapamil
Name some of the diseases that can cause constipation
o Hypothyroidism, diabetes, hypercalcemia, bowel cancer or obstruction, neurological injuries and diseases such as MS, Parkinson’s disease, dementia and depression
• Chronic constipation does not predict bowel cancer
How do you manage constipation?
Lifestyle and diet! • Exercise o Reduces intestinal transit time o Stimulates regular bowel • Respond to the urge! o After waking, meals or exercise o Position education • Fluids to prevent dehydration • Reer for further investigation o Patients >50 • New onset or worsening symptoms • Alarm symptoms • Dietary Fibre
What are some dietary fibres we can include?
o Complex carbohydrates from plants
• Not digested in SI, and only partly in LI
• Insoluble fibre, eg. Vegetables, fruits, nuts, wholegrain, weat, brown rice, pumpkin and sunflower seeds
• Roughage, adds bulk to faeces and decreases transit time
• Soluble Fibre: oats, barely, apricots, bananas, cherries, grapefruit, and plums.
• High water holding capacity decrease water reabsorption in the LI
o Increase fibre content of diet gradually to reduce flatulence
o Not advisable in all patients- eg. Irritable bowel syndrome, may worse symptoms
Name some Polyols we can use for constipation
o Sorbitols, mannitol, xylitol
o Poorly absorbed in GIT
• Not considered dietary fibre
o Can cause bloating and wind due to fermentation within LI
o Occur naturaly in foods: apples, pears, stone fruits – high in pear and prune juice- “natural laxatives’
What are some ‘alarm symptoms’ that can be associated with more serious conditions?
- Acute or recent constipation
- Obstipation
- Rectal blood loss, melaena or mucous
- Weight loss
- Fever
- Rectal pain
- Change in stool caliber
- Anorexia, nausea, vomiting
- Family history of inflammatory bowel disease or colorectal cancer
- Aged over 50 years
Pharmacological treatment considered if constipation persists AFTER lifestyle changes. What medications?
• Bulking agents
• Osmotic laxatives
• Stimulant laxatives
o Long term use is not recommended
- Not good evidence to guide treatment
- However, long term treatment with bulking agents or lactulose is considered safe
- Specialist assessment is required if constipation remains refractory to treatment
Purgatives- Bulk Laxatives
• Bran, methylcellulose, sterculia agar
• Psyllium powder – Metamucil (plant derivative)
o All are polysaccharide polymers not broken down in the upper GIT (hence not really dietary fiber)
o They are hydrophilic organic polymers that sequester water in the stools (the big fiber load draws water into the gut)
o Forms a bulk hydrated mass (lots of water) leading to increased peristalsis thus improving feacal consistency
o Slow to act (days) but they have no side effects (as long as they are introduced gradually)
• Rapid increase in dose can cause flatulence & distension (bloating)
o Good fluid intake must be maintained or they wont work
• Onset of action 48-72 hours
o Important depending on how quickly you need to relive the patient
o Useful table in Therapeutic Guidelines Table 12 P154 (2006)
Purgatives: Osmotic Laxatives- what are the two types
Saline Purgatives
Lactulose
Purgatives: Osmotic Laxatives
SALINE PURGATIVES
Combine with polyol containing fruit juice (pear or prune juice)
Saline Purgatives
• More like salts => Saline purgatives (isotonic or hypotonic)
o Magnesium sulfate & magnesium hydroxide
o Increase osmotic load in the GIT Lumen ⇒ increasing fluid drawn into the GIT (due to increased salt) ⇒ increases transit of GIT contents into the colon ⇒ distension of the colon ⇒ purgation within an hour! (much faster acting)
• Onset of action
o Oral 0.5 – 3 hrs, rectal 2-30 mins
• Sides effects (Particular in children or in renal-compromised patients)
o Abdominal cramps
o Salts can cause heart block, neuromuscular block or CNS depression => use guidelines
