Severe acute diarrhoea Flashcards
Name a common cause of a single episode of diarrhoea?
Dietary indiscretion
Anxiety
What is the significance of large-volume, watery stools?
There is always an organic cause
What are the implications of blood diarrhoea?
Colonic disease
Rectal disease
How long will an acute infective cause of diarrhoea last?
2-3 days
When should Inflammatory bowel disease be considered?
Severe or prolonged symptoms
What investigation is used to exclude infective causes of diarrhoea?
Stool culture
Name the 2 broad categories of aetiology of diarrhoea, and differentiate between them
Organic cause (Stool >250g/d) Functional cause
Which features suggest an infective cause of diarrhoea?
Sudden onset of bowel frequency
Crampy abdominal pain
Fever
Which features suggest an inflammatory cause of diarrhoea?
Bowel frequency
Loose, blood-stained stools
Pus
Which features suggest steatorrhoea?
Pale, offensive stools that float
Loss of appetite
Weight loss
What features suggest an organic cause of diarrhoea?
Nocturnal bowel frequency
Urgency
What features suggest a functional cause of diarrhoea?
Frequent
Small-volume stools
Define steatorrhoea
The presence of excess fat in faeces, due to fat malabsorption.
Produces a pale, offensive stool that floats.
Name 3 common causes of diarrhoea
Gastroenteritis Parasites/protozoa Irritable bowel syndrome Crohn's disease and Ulcerative Colitis Coeliac disease Colorectal cancer
Name 3 less common causes of diarrhoea
Microscopic colitis Chronic pancreatitis Bile salt malabsorption Laxative abuse Lactose intolerance Diverticular disease Overflow diarrhoea C. difficile
Name 2 non-GI or rare causes of diarrhoea
Thyrotoxicosis Autonomic neuropathy Addison's disease Ischaemic colitis Gastrinoma e.g. Zollinger-Ellison syndrome Carcinoid (neuroendocrine tumours)
Name 3 drugs that cause diarrhoea
Antibiotics Laxatives NSAIDs PPI Alcohol Psychotropic drugs: SSRIs etc.
State the different types of pathophysiology in diarrhoea
Osmotic
Secretory
Inflammatory
Abnormal motility
Describe the pathophysiology of osmotic diarrhoea
Presence of large quantities of hypertonic substances in the gut lumen ➔ fluid is drawn into the lumen
Describe the pathophysiology of secretory diarrhoea
Active intestinal secretion of fluid and electrolytes (Cl- secretion into lumen), and decreased absorption
Outline the causes of osmotic diarrhoea
Ingestion of non-absorbable substances e.g. MgSO4
General malabsorption
Specific absorptive defects e.g. Disaccharidase deficiency
Outline the common causes of secretory diarrhoea
Enterotoxins e.g. E. coli, cholera, C. difficile
Hormones e.g. VIPoma (Vasoactive intestinal peptide)
Bile salts following ileal resection
Fatty acids following ileal resection
Some laxatives
Describe the pathophysiology of inflammatory diarrhoea
Damage to intestinal mucosal cells ➔ fluid and blood loss, and defective fluid and electrolyte absorption
Outline the common causes of inflammatory diarrhoea
Infective causes e.g. Shigella ➔ dysentry
Inflammatory bowel disease
Name 2 medical conditions that cause diarrhoea due to abnormal motility
Diabetic diarrhoea
Hyperthyroid diarrhoea
Post-vagotomy diarrhoea
What clinical features are associated with acute diarrhoea?
Fever
Abdominal pain
Vomiting
Dehydration and hypokalaemia (severe)
Which patients are particularly susceptible to dehydration secondary to diarrhoea?
Very young
Very old
What is the duration of acute diarrhoea?
Under 2 weeks
Name 3 considerations if bloody diarrhoea occurs
Campylobacter Shigella/salmonella E. coli IBD Colorectal cancer Colonic polyps Ischaemic colitis
Name 2 consideration if mucus appear in diarrhoea
Irritable bowel syndrome
Colorectal cancer
Polyps
Name 2 considerations if frank pus occurs
IBD
Diverticulitis
Fistula/abscess
Name 2 considerations for explosive diarrhoea
Cholera
Giardia
Yersinia
Rotavirus
When are investigations necessary for a presentation of diarrhoea?
If the diarrhoea has lasted more than 1 week
What initial investigations should be taken in cases of diarrhoea?
Stool culture: bacterial pathogens, ova, cysts, parasites, C. difficile
FBC, CRP, U&E, TSH
Coeliac serology
Following initial investigations for diarrhoea, what investigations should occur next?
Sigmoidoscopy
Rectal biopsy
(Colonoscopy if necessary)
What is the maximum duration of viral/bacterial infective diarrhoea?
7-10 days
What is the most likely cause of diarrhoea if duration exceeds 10 days?
Inflammatory bowel disease
Outline the management of acute diarrhoea
Treat underlying cause
Food handlers should avoid work till stool samples -ve
Oral rehydration
Otherwise, 0.9% saline + 22mmol K+ per L
Codeine phosphate or Loperamide after each loose stool
Avoid antibiotics
Why is Codeine phosphate or Loperamide taken during diarrhoea?
Anti-motility drugs: decrease the frequency of passing stool
Why is colitis a contraindication for Codeine phosphate or Loperamide?
Both may precipitate toxic megacolon
What can be given in Antibiotic-associated diarrhoea?
Probiotics (e.g. Lactobacilli)
Describe the mechanism of action of Anti-motility drugs (Codeine phosphate and Loperamide)
Bind to opioid mu-receptors ➔ slow motility and increase anal tone
What are the 3 commonest causes of gastroenteritis?
Norovirus
Rotavirus (children)
Contaminated food (Shigella, S. aureus, Salmonella etc.)
How long does norovirus infection last?
Short-duration: 12-60 hours
What is the typical presentation of norovirus infection?
Fever
Nausea
Projectile vomiting
Watery diarrhoea
Describe the management of norovirus infection
Supportive management of fluids and electrolytes.
Norovirus is self-limiting.
What measure should be taken if a norovirus outbreak occurs on the ward?
Healthcare quarantine, due to its highly infectious (faecal-oral and aerosol) nature up to 48hr after resolution.
What is the typical presentation of rotavirus infection?
Vomiting
Watery diarrhoea
Hyperactive bowel sounds
(Adults have much milder symptoms)
What intervention has reduced NaV due to rotavirus by 50%?
Rotavirus vaccinations - given to infants alongside other routine vaccinations.
Define traveller’s diarrhoea
Any diarrhoea experience within the first two weeks of travelling abroad.
What proportion of travellers experience traveller’s diarrhoea?
60%
Why is Clostridium difficile difficult to contain in healthcare settings?
It is extremely contagious and resilient to both heat and alcohol-gel.
What investigation should be taken in suspected C. diff infection?
Stool culture for C. diff enterotoxin
What is the initial treatment for C. diff infection?
Stop causative antibiotic
If symptomatic, give metronidazole up to 400mg/8h PO for 10d max
What can be given in severe C. diff infections?
Vancomycin 125mg/6hr PO
