Diarrhoea Flashcards by Amrita Heer

What is the second commonest cause of death in children under 5?

Diarrhoea obvs

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Red flags for cancer relating to diarrhoea

Change in bowel habit
Bleeding
Weight loss unintentional
FH bowel or ovarian cancer
>50 and for >6 weeks
Anaemia
Abdominal or rectal mass

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Define diarrhoea

> 200g stool in 24 hours
OR
more than 3 stools a day and loose stools

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What is the normal bowel output?

3 x a day to 3 x a week

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How much fluid goes into the GI tract in a day?

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How much fluid goes out of the GI tract in a day?

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What are the sources of fluid input?

saliva - 1L
intestine - 1L
bile - 1L
pancreatic secretions = 2L
gastric secretions - 2L
diet - 2L

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What are the source of fluid output?

faeces - 0.1L
colon - 1.5L
ileum - 3.4L
jejunum - 4L

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Where does absorption in the intestines occur?

Intestinal villi

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Where does excretion occur in the intestines?

Crypts

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What is absorbed in the intestines?

Nutrients
Water
Electrolytes

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What is excreted in the intestines?

Water

Electrolytes

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What to ask about in a history of diarrhoea?

Duration
Type of stool and frequency
Organic features: BO at night, fever, blood
Systemic disease: diabetes, thyrotoxicosis, systemic sclerosis
H/O pancreatic disease or abdominal surgery
FH: IBD, malignancy, coeliac
Travel
Dietary indiscretion (including alcohol)
Meds: NSAIDs, ABs, PPIs, laxatives

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Define acute diarrhoea

Less than 2 weeks

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Define chronic diarrhoea

More than 4 weeks

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Symptoms of acute vs. chronic diarrhoea

Watery/bloody
vs.
Watery, blood, steatorrhea

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Define indeterminant diarrhoea?

In between 2w and 4w

Between acute and chronic

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What is the common cause of diarrhoea?

Infection

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Acute diarrhoea features

Mild

Self limiting

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Causes of acute diarrhoea

Dietary indiscretion (few hours)
Viral infection (24-48 hours)
Food poisoning
Traveller’s diarrhoea (2-5 days)

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Treatment for acute diarrhoea

Watch and wait
ORS - oral rehydration therapy if severe
Culture if severe and persists

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What is the most common cause for acute traveller’s diarrhoea?

ETEC - enterotoxicigenic E coli

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What are the causes for acute travellers diarrhoea?

ETEC - enterotoxicigenic E coli (50%)
Other bacteria (25%)
Parasites (15%)
Viruses (10%)

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What other bacteria can cause acute travellers diarrhoea?

Shigella spp
Salmonella spp
Campylobacter spp
EHEC
EIEC
V. cholerae &amp; other vibrios

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What parasites can cause acute travellers diarrhoea?

``` G. intestinalis C parvum Microsporidia I. belli Cyclospora E. histolytica ```

What viruses can cause acute travellers diarrhoea?

Rotavirus Adenovirus SRSVs Norovirus - in schools/hospitals/cruise ships

Oral rehydration for acute diarrhoea

``` 1L water 3.5 sodium chloride 2.5 sodium bicarbonate 1.5g potassium chloride 20g glucose ```

When to consider IV fluids and ABs in acute diarrhoea?

``` Elderly Immunocompromised Frequent bloody stools Severe abdominal pain Temp>38.5 degrees Hypovolaemia ```

Causes of watery chronic diarrhoea?

Secretory | osmotic

Causes of bloody chronic diarrhoea

Colonic disease Infection/inflammation Neoplasia

Causes of fatty/steatorrhea like chronic diarrhoea?

Pancreatic Small bowel (failure of fat absorption)

Features of pancreatic insufficiency causing steatorrhea

``` Normal red cell folate Faecal fat >20g in 24 hours (normal is <7g) Faecal elastase favoured over faecal fat Plain abdominal radiograph/US Abdominal CT, EUS< MRI, MRCP ERCP ```

Features of small intestinal disease causing steatorrhea

Low red cell folate Anti-TTG AB Duodenal/jejunal/TI biopsy Small bowel imaging - CT/MRI

What do you need to be sure of when measuring anti-TTG AB?

Measure IgA to make sure there is no IgA deficiency as this will cause a false negative test

Clues to toxin producing organism causing diarrhoea

Rapid onset of symptoms after food <6h = (S. aureus, B. cereus)

B. cereus source

Rice

S. aureus source

Creamy products

What can fever be indicative of in diarrhoea?

``` Invasive bacteria (Salmonella, Shigella, Campylobacter) Enteric viruses Cytotoxic organism (C. difficile, E. histolytica) ```

What can bloody diarrhoea be indicative of in diarrhoea?

``` Invasive bacteria (Salmonella, Shigella, Campylobacter, E. coli) Amoebic dysentery (travel history) ```

If a patient is on ABs and they get diarrhoea what might cause it?

C. difficile

What drugs can cause chronic diarrhoea?

``` Alcohol ABs Anti-depressants (lithium, SSRIs) Anti-hypertensives Cholesterol lowering agents GI drugs (Mg2+, H2RA, PG analogs, 5-ASA) NSAIDs Oral hypoglycaemics (biguanides) ```

Osmotic diarrhoea causes

Nonabsorbable substance High concentration of solute in malabsorption Specific defect e.g. disaccharide deficiency

Secretory diarrhoea causes?

``` Inflammation = IBD Infection = salmonella Enterotoxins from e.g. E coli, cholera Hormones e.g. neuroendocrine tumours Bile salts and fatty acids ```

Motility related causes of diarrhoea

Thyrotoxicosis IBS DM autonomic neuropathy

What is the most commonest cause of maldigestion?

Lactose intolerance | Important cause of diarrhoea

FODMAP related diarrhoea

``` Poorly absorbed substances in diet F = fermentable O = oligosaccharides D = disaccharides (lactose) M = monosaccharides (fructose) P = polyols ``` (eliminate items then slowly introduce one by one can cause resolution of symptoms)

Clostrium Difficile

``` Anaerobic Gram positive Spore forming Faecal oral route Toxins A & B which cause disease Associated with AB use Elderly IBD patients more prominent Life threatening ```

Mild C difficile define

3 stools per day | Normal WCC

Moderate C difficile define

3-5 stools per day | Raised WCC

Severe C difficile define

WCC>20 Temperature >38.6 Raised Cr Abdo pain or XR acute colitis

Complicated C. difficile define

Hypotension, partial ileus | Evidence of severe disease on CT

Life threatening C difficile define

Complete ileus or toxic megacolon

Mild C difficile Tx

Oral metro

Moderate C. difficile Tx

Oral metro

Severe C. difficile Tx

Oral vanco

Complicated C. difficile Tx

Oral vanco + IV metro

Life threatening C. difficile Tx

Oral vanco + IV metro Faecel microbiota transplant Consider colectomy

Blood test for diarrhoea Ix

``` FBC = anaemia Inflammatory markers = WCC, platelets, CRP U&E = dehydration/AKI Albumin, Ca, P = nutritional status Haematinics TTG AB and IgA TFTs ```

Stool and other tests for diarrhoea

Stool weight MC&S, C. difficile toxin, cysts, ova, parasites Faecal calprotectin (increased in inflammation so IBD/infection) FIT (faecal immunochemical test for Hb) Faecal elastase Stool pH/electrolytes/reducing substances BMI/nutritional status

Other imaging for diarrhoea

``` Duodenal biopsy Colonoscopy Small bowel MRI Video capsule endoscopy Cross sectional imaging with CT ```

Prevention of diarrhoea

Hand washing - soap and water!