Diarrhoea

Question 1

What are the common causes for diarrhoea?

Answer 1

Gastroenteritis
Parasites/protozoa
IBS
Colorectal cancer
Crohn's disease, UC, Coeliac's disease

Question 2

What are the ‘less common’ causes for diarrhoea?

Answer 2

Microscopic colitis
Chronic pancreatitis
Laxative abuse
Lactose intolerance
Overflow diarrhoea
Diverticular disease
Bacterial overgrowth
C. Difficile

Question 3

Non-GI causes or rare causes for diarrhoea?

Answer 3

Thyrotoxicosis
Autoimmune neuropathy
Addison's disease
Ischaemic coliticc
Amyloid
gastrinoma

Drugs: Antibiotics, PPI, NSAIDs, Laxatives, Propranolol, digoxin, alcohol

Question 4

Describe the different types of diarrhoea

Answer 4

Diarrhoea = decreased stool consistency from water fat (steatorrhoea) or inflammatory discharge.
Watery discharge is osmotic (e.g. laxative induced), secretory (e.g. microscopic colitis) or functional (e.g. IBS).

Steatorrhoea is characterised by increased gas, offensive smell, floating and hard to flush. Examples include: Giardiasis, Coeliac’s disease

Inflammatory diarrhoea (crohn’s and UC) often have blood and pus in the stool.

Question 5

Questions to ask about diarrhoea and what they suggest

Answer 5

Acute or chronic??

• Acute = gastroenteritis
• Chronic (alternating with constipation) = bowel irritation

Weight loss, nocturnal diarrhoea and anaemia?
= Close follow up (?IBD)

Bloody diarrhoea?
= Campylobacter, shigella, salmonella, E.coli
= UC or crohn’s
= Colorectal cancer,
= Colonic polyps
= Pseudomembranous colitis, ischaemic colitis

Mucus in diarrhoea?
= IBS, colorectal cancer, polyps

Frank pus?
= IBD, diverticulitis, fistula/abscess

Explosive diarrhoea?
= Cholera, Rotavirus

Large bowel symptoms?
= Watery stool +/blood/mucus
= Pelvic pain relieved by defecation
= Tenesmus
= Urgency

Small bowel symptoms:
= Peri-umbilical (or RIF) pain not relieved by defecation

Question 6

What other signs might be present in a patient with diarrhoea?

Answer 6

Dehydration - dry mucous membranes, decreased skin turgor, increased capillary refill time, shock

Fever (infection)

Weight loss, clubbing, anaemia (cancer, IBD, coeliac)

Rashes (infection)

Abdominal mass (cancer)

Goitre/hyperthyroid signs (hyperthyroidism)

Question 7

Which investigations might you do and what would they show?

Answer 7

FBC:

• ↓ MVC = Fe deficiency (colon cancer/coeliac)
• ↑ MVC = alcohol abuse or B12 deficiency (coeliac/crohn’s)

ESR/CRP:
↑ = infection, crohn’s or colitis

U&E
↓ potassium = severe diarrhoea/vomiting

TSH
↓ = thyrotoxicosis

Coeliac serology

Stool culture
= infections

Rigid sigmoidoscopy
= Crohn’s, UC, diverticular disease, cancer

Colonoscopy
= Malignancy, colitis,

Question 8

How should diarrhoea be managed?

Answer 8

Treat cause
Oral/ IV re-hydration
Codeine phosphate/ Loperamide (anti-diarrhoeals)

Question 9

How do you manage infective diarrhoea?

*flowchart

Answer 9

? no systemic signs
–> Symptomatic treatment, stool culture not needed

Systemic illness (fever >39, dehydration, diarrhoea +visible blood for >2 weeks)

• –> admit to hospital, oral fluids, consider antibiotics
• –> prompt direct faecal spears
  
  • -> polymorphs seen? = shigella, campylobacter, E.coli
  • -> no polymorphs seen? = Salmonella, E.coli, C.diff

Special circumstances (food poisoning outbreak, travel, recent antibiotics, rectal intercourse, immuno-compromised, raw seafood ingestion)

• –> routine culture and microscopy
• –> ask microbiologist about specific treatment