Diarrhoea Flashcards
Acute diarrhoea
Abnormal passage of loose stools 3+ times a day.
Volume of stool 200g/day
Acute- lasts less than 4 weeks
Cause: Most likely infectious
Most likely to resolve, investigate after a week
Chronic diarrhoea
Diarrhoea lasting more than 4 weeks.
Cause: chronic pathology like an inflammatory disease
Viral cause of diarrhoea [3]
Most likely to cause acute diarrhoea:
- Rotavirus
- Norovirus
- Enteric adenovirus
Bacterial cause of diarrhoea [4]
Salmonella
Shigella
Campylobacter
S.aureus
Parasitic cause of diarrhoea [3]
Cryptosporidium parvum
Giardia lamblia
Entamoeba histolytica
Colonic causes of chronic diarrhoea
Ulcerative and Crohn’s colitis.
Microscopic colitis.
Colorectal cancer
Small bowel cause of chronic diarrhoea
Coeliac disease
Crohn’s disease
Bile salt malabsorption
Lactose intolerance
Small bowel bacterial overgrowth- small bowel is supposed to be sterile
Pancreatic cause of chronic diarrhoea
Chronic pancreatitis
Pancreatic cancer
Cystic fibrosis
Endocrine causes of chronic diarrhoea
Hyperthyroidism
Diabetes
Addison’s disease
Hormone secreting tumors.
Mechanisms diarrhoea [7]
Osmotic: water is drawn from the blood. e.g lactose intolerance
Steatorrhoea: Fat malabsorption
Secretory: secretion of toxins/ hormone dysfunction.
- E.coli
- Cholera
Inflammatory: Crohn’s, ulcerative colitis
Neoplastic
Ischaemic
Post irradiation
Investigations for diarrhoea
Stool tests
Blood test
Colonoscopy
CT
Video capsule
MRI small bowel
Examination for diarrhoea
Tenderness when palpating abdomen?
Anal examination: visual inspection
- amount of stool in anus
Stool examination
Rigid sigmoidoscopy: inspects rectal mucosa to help exclude UC
Ulcerative colitis
Continuous mucosal inflammation of the colon.
- No granulomas on biopsy
- Affects the rectum
Crohn’s disease
Discontinuous inflammation affecting any area of the GI tract.
- Often transmural and contains granulomas
Distribution, mainly:
Terminal ileum
Colon
Ileo-colic
Endoscopic appearance of Crohn’s disease
- Patchy erythema
- Cobblestone mucosa
Stool test investigation
Used to diagnose cause of diarrhoea.
- Culture of microbes: bacteria?
- Faecal elastase:
Symptoms of ulcerative colitis
[5]
Blood diarrhoea
Rectal bleeding
Mucus in faeces
Abdominal pain
Nocturnal defecation
Extraintestinal manifestations of ulcerative colitis
Arthritis
Uveitis
Erythema nodosum
Pyoderma gangrenosum
Primary sclerosing cholangitis
Treatment of severe ulcerative colitis
Hospital admission
Hydrocortisone
Heparin
Daily c-reactive protein test
Drug to AVOID when treating sever UC
NSAIDs
Opiates
Antimotility agents
Treatment for patients with severe UC who fail to respond to steroids
Infliximab
Cyclosporin
Colectomy
Treatment for mild-moderate UC
Mesalazine
Prednisolone
Azathioprine
Anti-TNF agents
Surgery possibly
Epidemiology of Crohn’s disease
Mainly affects teens/young adults
Affects both sexes equally
Presents in a relapsing/remitting course
Associated with smoking
Previous appendectomy
Risk increased with infectious gastroenteritis
Crohn’s disease symptoms
Chronic diarrhoea
Abdominal pain and weight loss are very common
Anaemia
Growth failure in children
Crohn’s disease pathology
Any part of the GI tract- discontinuous fashion
Transmural inflammation
Deep ulcers
Fissures
Fistulas
Abscesses
Perianal
Similarities between UC and Crohn’s disease
Both affect any age and peak ages 20-40.
Both Inflammatory bowel diseases
Both show diarrhoea
Both have extraintestinal manifestation
Differences between UC and Crohn’s disease [4]
UC: affects only the colon, continuously.
Crohn’s: affects any part of the GI, discontinuously.
UC affects more people in the population
UC: mucosal inflammation
Crohn’s: transmural inflammation
Crohn’s presents with deep ulcers and fissures, fistulas and abscesses- UC doesn’t really.
