Diarrhoea Flashcards
Define diarrhoea.
An increase in the amount of stool passed daily to over 300 g of stool/day. This is usually accompanied by increased frequency and loosening of the stools.
Normal: 3/day to 3/week
What other types of stool may diarrhoea be mistaken for?
Haematochezia
Melaena
Steatorrhoea
Loose stools (soft faeces with no increase in frequency or quantity)
List 6 main mechanisms of diarrhoea.
Infection Inflammation Increased bowel motility Malabsorption Medications
For each of the mechanisms, list some causes: Infection Inflammation Increased bowel motility Malabsorption Medications
- Infection Infectious diarrhoea - Inflammation Inflammatory bowel disease Diverticular disease - Increased bowel motility IBS Hyperthyroidism - Malabsorption Coeliac disease Pancreatic insufficiency Overflow Diarrhoea Hard faeces stuck in the bowel Colon cancer or ovarian cancer - Medications Laxatives Colchicine Digoxin Antibiotics Metformin Thiazide diuretics
What is the differential diagnosis for diarrhoea in young people?
Infective diarrhoea Irritable bowel syndrome Inflammatory bowel disease Coeliac disease Medications Hyperthyroidism
Describe the distribution in the incidence of inflammatory bowel disease.
Bimodal distribution with peaks in the 20s and 40s
What is the differential diagnosis for diarrhoea in elderly people?
Neoplastic disease (villous polyps, colorectal cancer, pancreatic cancer) Diverticular disease Ischaemic colitis Overflow diarrhoea Bacterial overgrowth Microscopic colitis
What are the first factors to consider in the immediate management of a patient with diarrhoea?
ABC
Dehydration – check heart rate, blood pressure, mucous membranes
Electrolytes and pH disturbance
What are the three major consequences of severe diarrhoea?
Shock
Acidosis
Hypokalaemia
List some questions that you would ask about the character of the stools.
Have the stools been mucoid or jelly-like?
Have the stools been foul-smelling, floating and difficult to flush away?
Have the stools been unusually pale?
Has there been blood in the stool?
State two causes of mucoid diarrhoea.
Salmonella
Villous polyps
What could cause foul-smelling and floating diarrhoea?
Malabsorption (due to coeliac disease, biliary outflow obstruction, pancreatic insufficiency)
What do pale stools suggest?
Biliary outflow obstruction
NOTE: you could ask about dark urine as well
List some questions that you would ask about the patient’s bowel habit.
Have you been having diarrhoea at night?
Have you found yourself rushing to the toilet to poo?
After passing motions, do you ever feel like you haven’t fully evacuated your bowels?
Have the bowel habits been variable? Have you also experienced periods of constipation?
How often do you get diarrhoea?
Which causes of diarrhoea is faecal urgency suggestive of?
Infective diarrhoea
IBD
What is tenesmus* and what does it suggest?
*tenesmus = recurrent inclination to empty bowels
Continual or recurrent feeling of having to empty your bowels even if there is nothing coming out
This suggests that there is a space-occupying lesion in the rectum
Which diagnoses are associated with causing with a variable bowel habit with bouts of both diarrhoea and constipation?
IBS (more in the young) Colorectal caner (more in the elderly)
List some key associated symptoms that you should ask the patient about.
Vomiting
Abdominal pain
Unintentional weight loss
Eye, skin and joint problems
Which differential causes diarrhoea and vomiting?
Gastroenteritis (infective diarrhoea)
What would RIF pain associated with diarrhoea suggest?
Crohn’s disease (the pain is caused by inflammation of the terminal ileum)
What would LIF pain associated with diarrhoea suggest?
Diverticular disease
Why is it important to classify how rapidly a patient suffering from diarrhoea has lost weight?
Acute diarrhoea (due to infection) can cause rapid weight loss Weight loss over months is suggestive of chronic disease (e.g. IBD, cancer)
List some extra-GI features of inflammatory bowel disease.
Uveitis/Scleritis/Episcleritis Erythema nodosum Pyoderma gangrenosum Aphthous ulcers Enteric arthritis
List some risk factors for diarrhoea.
Recent travel abroad Eating unusual food Knowing people with similar symptoms Stress Low-fibre diet Medications
List some important diseases in the family that should be inquired about.
FAP HNPCC Colorectal cancer IBD Coeliac disease
List some causes of diarrhoea that are associated with finger clubbing.
Crohn’s disease
Ulcerative colitis
Coeliac disease
Hyperthyroidism
What is the name given to the itchy rash that is associated with Coeliac disease?
Dermatitis herpetiformis
Why is it important to do a full blood count in patients presenting with diarrhoea?
Coeliac disease, UC and Crohn’s disease can all cause anaemia due to malabsorption of iron, B12 and folate
NOTE: UC can also cause anaemia due to blood loss
NOTE: IBD can also cause a raised platelet count (due to inflammation)
Describe the use of ESR/CRP in patients with diarrhoea.
Crohn’s and UC are systemic inflammatory conditions so cause a raised ESR
Infective diarrhoea causes a high CRP
What is the main diagnostic blood test used for Coeliac disease?
Tissue transglutaminase (TTG)
Why is it important to check IgA levels when performing a TTG?
IgA deficiency can give a false-negative result
List two other tests that can be performed to diagnose Coeliac disease.
Anti-endomysial antibodies
Anti-gliadin antibodies
List some other blood tests that may be useful when investigating a patient with diarrhoea.
TFTs – check for hyperthyroidism
U&Es – diarrhoea causes dehydration and electrolyte derangement
Albumin – can indicate malabsorption
List some faeces tests that may be performed in a patient with diarrhoea.
Faecal MC&S – identify organism that may be causing infective diarrhoea
C. difficile toxin test
FOBT
What is a major risk factor for C. difficile colitis?
Use of antibiotics
List some differences between Crohn’s disease and Ulcerative colitis in terms of the history of presenting complaint.
- Crohn’s Disease
RIF pain due to inflammation of terminal ileum
Weight loss and failure to thrive in between attacks - Ulcerative Colitis
Diffuse pain
Bloody diarrhoea
Relatively will between attacks
List some forms of imaging that may be used in patients with diarrhoea.
Abdominal X-ray
Colonoscopy
Double-contrast barium enema
Describe the typical presentation of infectious diarrhoea.
Single, acute episode of sudden-onset diarrhoea and vomiting after a meal that was potentially undercooked or allowed to stay warm for long periods of time
What are the two organisms most commonly associated with causing food poisoning?
Staphylococcus aureus
Bacillus cereus
What is the difference between food poisoning and infectious diarrhoea?
Food poisoning = due to the presence of toxins
Infectious diarrhoea = due to the presence of pathogens
Outline the management of infectious diarrhoea and food poisoning.
Oral rehydration
Stay away from work for at least 48 after the diarrhoea ends
Oral rehydration salts may be used
What criteria are used to diagnose IBS?
ROME III Criteria
Outline the management of IBS.
Reassure
Antispasmodics (e.g. loperamide)
Antidepressants (slow down GI transit)
Diet and herbal remedies
Outline the management of C. difficile colitis.
ABC Faecal analysis (for C. difficile toxin) Isolate Meticulous hygiene Antibiotics Address precipitants (e.g. antibiotic or PPI use)
Which antibiotic is used to treat C. difficile colitis?
Oral metronidazole
NOTE: oral vancomycin is used in refractory cases
Why might an abdominal X-ray be performed in patients with C. difficile colitis?
C. difficile colitis can lead to toxic megacolon
Describe the typical presentation of patients with ulcerative colitis.
Young patient presenting with painless bloody diarrhoea (they may also complain of diffuse abdominal pain)
List some conditions that UC is strongly associated with.
Colorectal adenocarcinoma
Cholangiocarcinoma
Primary sclerosing cholangitis
Describe the medical management of UC.
Aminosalicylates
Immunosuppressive drugs such as methotrexate, azathioprine, corticosteroids and anti-TNF antibodies may also be used
Describe the surgical management of UC.
Removal of the affected portion of bowel
This used to leave many patients with a life-long end colostomy
Recently, surgeons have started doing ileal pouch-anal anastomosis, which allows almost normal defecation
What can overflow diarrhoea be caused by?
Hard faeces stuck in the bowel
Masses within the bowel wall (e.g. colorectal cancer)
Masses outside the bowel wall (e.g. large ovarian tumour)
What will happen if you perform a DRE on a patient with overflow diarrhoea?
It will cause a gush of fluid and flatus
Which antibodies are raised in Graves’ disease?
Anti-thyroid peroxidase antibodies
NOTE: this is also raised in Hashimoto’s thyroiditis
