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
