Diarrhoea, constipation and GI care Flashcards
How do we define diarrhoea
A change in bowel habit
Substantially more frequent and looser stools than usual
Consistency more significant than frequency
World Health Organization 2017 “the passage of three or more loose or liquid stools per day (or more frequent passage than is normal for the individual)”
Can be categorised as:
Acute - < 14 days
Persistent - > 14 days but less than 28 days
Chronic > 28 days
What is the pathophysiology of diarrhoea (ie. what mechanisms cause it)
Increased osmotic load in gut lumen
Increase in secretion
Inflammation of intestinal lining
Increased intestinal motility
More than one of these mechanisms can cause it
What causes actue diarrhoea
Usually due to infection or ingestion of toxins (contaminated food)
Infection:
Bacterial e.g. Campylobacter, Escherischia coli, Salmonella
Viruses e.g. rotavirus or norovirus
Other causes drugs, parasites, anxiety
Most cases – self-limiting and resolve within 72 hours
We can give treatments for symptomatic relief
What notable diseases cause actue diarrhoea
Dysentery
Food poisoning
Rotavirus uncommen in adults
Norovirus common cause winter vomiting bug
What is travellers diarrhoea
Diarrhoea experienced by travellers or holiday makers
We should consider destination, age, diet
Early onset, usually within first few days of trip
Symptoms as per acute diarrhoea but can also have blood diarrhoea (in the cases of dysentery)
Usually resolve within 7 days
What organisms can cause travellers diarrhoea
Causes include: Enterotoxigenic Escherichia coli (ETEC), Campylobacter Salmonella Enterohaemorrhagic E coli and Shigella, Viruses, protozoa and helminths
Some infections e.g. giardiasis and amoebic dysentery can cause persistent or recurrent diarrhoea or systemic complications
How can we prevent and treat travellers diarrhoea
Antibiotic prophylaxis is rarely recommended
Hygiene, food and drink advice including:
Wash hands thoroughly using soap
Antiseptic wipes/gel if no washing facilities available
Avoid drinking local water, even for cleaning teeth
Avoid ice cubes, dairy products, ice cream, home distilled drinks and salads
Fresh foods. “Cook it, boil it, peel it or leave it”
Avoid fish and shellfish unless sure fresh and not been near sewage outlet
Clean, hygienically run establishments
What can cause chronic diarrhoea
Many potential causes including:
Irritable bowel syndrome (IBS)
Inflammatory bowel disease (IBD)
Malabsorption syndromes e.g. coeliac disease, lactose intolerance
Metabolic disease e.g. diabetes, hyperthyroidism
Laxative abuse
What kind of questions must we ask people presenting with diarrhoea
Stool frequency Nature e.g. blood, mucus Occurrence – isolated or recurrent Duration Onset Timing Food Recent travel Medication
When should we refer adults with diarrhoea
If the symptoms are present for:
> 72 hours in healthy adults
> 48 hours in elderly
> 24 hours if diabetic
Associated severe vomiting and fever
History of change in bowel habit
Blood or mucus in stools
Suspected ADR
Alternating diarrhoea and constipation in elderly – could be faecal impaction
Weight loss
Recent hospital treatment or antibiotic treatment (may have c. difficile)
Evidence of dehydration
Severe pain/rectal pain
How do we treat minor diarrhoea
Primary aim is to prevent dehydration
Treatments include: Oral Rehydration Therapy Loperamide Morphine Diphenoxylate Adsorbents Antibiotics
What considerations must be thought of when designing oral rehydration therapies
Oral rehydration solutions (ORSs) should:
enhance the absorption of water and electrolytes
replace electrolyte deficit adequately and safely
contain alkalinising agent to counter acidosis
be slightly hypo-osmolar (about 250 mmol/litre) to prevent the possible induction of osmotic diarrhoea
be simple to use in hospital and at home
be palatable and acceptable, especially to children
be readily available
What are oral rehydration therapies made of
Generally contain:
Sodium and potassium to replace essential ions
Citrate and/or bicarbonate to correct acidosis
Glucose or another carbohydrate e.g. rice starch
(we must monitor diabetics carefully)
What is the pharmaclogy of loperamide
Synthetic opioid analogue - µ (mu) opioid receptor agonist (not much enters systemic circulation)
Direct action on opiate receptors in the gut wall
Extensive first-pass metabolism therefore little reaches systemic circulation
What are the doses of loperamide
Adult dose: Initially 4 mg, followed by 2 mg for up to 5 days, dose to be taken after each loose stool; usual dose 6–8 mg daily; maximum 16 mg per day.
What are the contraindications of loperaide an when should it be avoided
Contra-indications:
Active ulcerative colitis
Antibiotic associated colitis
Conditions where inhibition of peristalsis should be avoided
Conditions where abdominal distension develops
Avoid:
Bloody/suspected inflammatory diarrhoea
Significant abdominal pain
Why can loperamide be misused
It has a mild opioid affect which can be abused in very high doses. Causes serious cardiac adverse reactions though
When should anibiotics be used and whe shouldnt they be used to treat diarrhoea
Stool sample should be taken and causative organism identified before antibiotic given
Can also be used in severe infection (fever > 39oC and prolonged symptoms, in the elderly or immunocompromised)
Empiric use not recommended
What other drugs can we use to slow down the GI tract and hence reduce diarrhoeal symptoms (3)
Morphine
Direct action intestinal smooth muscle
Morphine content per recommended dose of products available OTC for diarrhoea ranges 0.5-1mg - ? effective
Diphenoxylate
Synthetic derivative of pethidine
Available as combination product – co-phenotrope (diphenoxylate hydrochloride 2.5mg/atropine 25mcg)
Adsorbents
Adsorb microbial toxins and micro-organisms
Kaolin (Kaolin and Morphine)
Bismuth subsalicylate
What advice should pharmacists give to patients presenting with diarrhoea
General management: Plenty of clear fluids Avoid drinks high in sugar Avoid milk and milky drinks Eat light, easily digested food
If gastroenteritis – infections. Precautions including not returning to work until symptom free for 48 hours, hygiene advice and cleaning of sanitary equipment
Note - Diarrhoea can reduce absorption of some medicines so it is important to check their medication history and advise accordingly
What is c. difficile and how does it link to diarrhoea
Clostridium difficile – spore producing anaerobic Gram-positive anaerobic bacterium
Asymptomatic commensal in 2-3% adult population
Patients prescribed antimicrobials- leading cause of antibiotic associated diarrhoea and can lead to pseudomembranous colitis
Common cause of healthcare-associated infections
What are the risk factors for c. difficile (both antibiotic associated and general risk factors)
Risk factors for Clostridium difficile infection (CDI) include:
Antimicrobial choice - Use of broad‑spectrum antibiotics is associated with an increased incidence of Clostridium difficile infection.
Strongly associated with the infection were clindamycin, cephalosporins and quinolones.
However, the interpretation of data on the risk of C. difficile with different antibiotics is extremely difficult
Antimicrobial duration
Acid-suppressing medications e.g. Proton Pump Inhibitors (PPIs) - altered gi environent
Age (older)
Hospitisation
Length of stay in hospital
Recent hospitalisation
Underlying morbidities e.g. do they have any co-morbidities
How do we manage c. diff infection
Stop acid-suppressing medication where possible (PPIs)
Stop concomitant antimicrobials if clinically appropriate
Stop any antimotility medicines e.g. loperamide (causes accumulation of the bacteria in the gut)
Maintain adequate fluid balance and avoid dehydration
Targeted C difficile antimicrobial treatment
Appropriate infection control procedures including handwashing (with soap and water) and isolation
How do we treat c. diff
Targeted antimicrobial treatment
Oral Metronidazole
- First-line for mild-moderate CDI
- Oral – 400mg tablet three times a day for 10-14 days
Oral Vancomycin
- Severe disease (can be used in mild-moderate as well)
- Oral – 125mg every 6 hours (can give up to 500mg every 6 hours)
Critically unwell – combination therapy of IV Metronidazole and oral Vancomycin
We dont wait for cultures before treatment - treat empirically first
Oral Fidaxomicin
Macrocyclic antibiotic – inhibits C difficile sporulation
Recurrent CDI and severe CDI with high risk recurrence
Oral – 200mg twice a day for 10 days
Sometimes used for recurrent infection
List 3 other treatments other than atimicrobials
Probiotics
Restore gut microbiome
Role uncertain in prevention and treatment
Faecal Microbiota Transplant (FMT)
Transplant from healthy donor
Some evidence to support this
Clinical trial stage
Intravenous Immunoglobulin
Severe or recurrent cases of colitis where other treatments failed
Define constipation
Passage of hard stools less frequently than normal
Typically less than three bowel movements in one week
What are the symptoms of constipation and who is most commonly affected
Symptoms include: Abdominal discomfort and distension Abdominal cramping Bloating Nausea Difficulty passing stool
Affects people of all ages
More common in:
Women, particularly if pregnant
Older people
What are the 2 different types of constipation
Functional (idiopathic)
No anatomical or physiological cause known
Secondary
Induced by particular condition or medicine
What factors can lead to constipation
Non-medical factors which pre-dispose to constipation include Inadequate fluid intake Inadequate dietary fibre Dieting Changes in lifestyle Suppressing the urge to defecate
Name some conditions which can predispose a person to constipation
Coeliac disease Depression Diabetes GI obstruction Irritable bowel syndrome Parkinson’s disease Hypercalcaemia Hypokalaemia Hypothyroidism
Name some medicines which can predispose a person to constipation
Medications that can cause constipation include:
Antacids containing aluminium and calcium
Antihypertensives – diuretics, calcium channel blockers
Antidepressants – tricyclics and some monoamine oxidase inhibitors
Antimuscarinics – procyclidine, oxybutynin
Antiparkinsonian medicines – levodopa, dopamine agonists, amantadine
Opioid analgesics
Iron
How do we assess a patient presenting with constipation
Bowel habit Examination Try to identify cause Check for red flags including; Unexplained weight loss Rectal bleeding Family history of colon cancer or IBD Signs of obstruction
What are the aims of constipation treatment
Aims:
Restore normal frequency defecation
Achieve regular, comfortable defecation
Avoid laxative dependence
Relieve discomfort
How do we treat constipation
Non-pharmacological: Consider primary cause Diet – increasing dietary fibre Ensuring adequate fluid intake Lifestyle measures including exercise
Laxatives: Bulk-forming Stimulant Osmotic Faecal-softening
How do bulk-forming laxatives work
Increase faecal mass through water binding to stimulate peristalsis
Take several days for full effect
Maintain good fluid intake as they laxatives pull in water
Can be used long-term in people prone to constipation
Examples include:
Ispaghula husk (fybogel)
Methylcellulose (also acts as softener)
How do stimulant laxatives work
Increase intestinal motility via muscle contractions
Work within a few hours (advise to take before bedtime, should work by morning)
Can cause abdominal cramps due to increased peristalsis
Avoid prolonged use – can lead to diarrhoea, fluid and electrolyte imbalance
Examples include:
Senna
Dantron (terminally ill patients only)
Bisacodyl
How do osmotic laxatives work
Work within colonic lumen to retain and draw water into intestine by osmosis to help soften and pass the stool
Patient must maintain good fluid intake
Macrogel powders –1-3 days to work
Lactulose (semi-synthetic disaccharide) – 2-3 days to work (dose is lower than the dose given in liver disease)
Phosphate enema or suppository – 15-30 minutes to work
Magnesium hydroxide – 3-6 hours to work
How do faecal softening laxatives work
Stimulate peristalsis by increasing faecal mass: act to lower surface tension and allow water and fats to penetrate faeces
Docusate sodium acts as faecal softener and stimulant – works within 1-3 days
Glycerol suppository – works within one hour
Arachis (peanut) oil enema – works within 30 minutes. Not to be used if nut allergy
What are some complications of constipation
Faecal Impaction
Haemorrhoids
Rectal prolapse
Anal fissures
What is coeliac disease
An autoimmune condition affecting the small intestine.
Has a genetic predisposition aspect and has environmental triggers
Body’s immune system attacks itself when gluten is eaten (adverse reaction to gluten)
The reaction is not an allergic reaction and does not cause anaphylactic shock (so its not an allergy or intolerance)
Affects 1% of Northern Europeans and Northern Americans
How do we diagnose coeliac disease (not examined)
Serology
IgA tTG vs IgA EMA (parts of the immune system)
Endoscopy for small intestinal biopsy
2nd part of duodenum
At least 4 large biopsies – well orientated
Repeat biopsy on gluten-free diet
Gluten challenge (>10g per day, 6/52)
What are the symptoms of coeliac disease
Not every patient has symptoms
Vary person to person from mild – severe
Include: Headaches Diarrhoea Abdominal pain Lethargy
The symptoms may last from a few hours to a few days
What are the complications of undiagnosed coeliac disease
Long term malabsorption and osteoporosis
Refractory coeliac disease
Ulcerative jejunitis
Enteropathy associated T cell lymphoma
Autoimmune disease
-T1DM, Autoimmune thyroid disease
The longer you continue eating gluten the more your risk of triggering another autoimmune disease.
How do we manage coeliac disease
There is no cure and the treatment is a life long gluten-free diet
All fresh meat, fish, cheese, eggs, milk, fruit and vegetables are gluten-free
Specially-manufactured wheat starch is used in the gluten-free diet
The Crossed Grain symbol is internationally recognised by those who have to follow a gluten-free diet.
Why is there low compliance with the gluten free diet
Taste- poor compliance in adolescents Expensive Difficult to eat out No agreed international consensus on permissible levels Range of symptoms with ingestion Nutritional aspects Low fibre Low vitamin D High calories
Can gluten free products be provided on prescription
As of4th December 2018, the prescribing of gluten-free (GF) foods on the NHS in England will be restricted to bread and mixes only
Define IBS
Its a chronic condition of at least 6 months of abdominal pain and bowel symptoms (diarrhoea, constipation or combination of both)
Cause unclear and can differ patient to patient
Poorly understood
Treatment aimed at symptomatic relief
How do we treat IBS
Number of different medications can be used
No “gold standard” as symptoms vary
Treatments include:
Dietary changes and exercise
Antispasmodics for cramping pain e.g. mebeverine, hyoscine, peppermint oil
Anti-diarrhoeal e.g. Loperamide
Laxatives e.g. bulk-forming, stimulant, osmotic
Probiotics
What are antispasmotics and give two example of them
Smooth muscle relaxants
Mebeverine is commonest prescribed drug for IBS in the UK
Modified release capsule – 200mg twice daily
Tends to be well tolerated
Peppermint oil capsules can also be used – taken three times daily
