MRCP PACES Approaches Approach to Diarrhoea

Differential diagnosis

  • Gastrointestinal
    • Gastroenteritis
      • Food history
      • Travel history
      • Sick contacts
      • HIV
    • Inflammatory bowel disease
    • Small bowel bacterial overgrowth
    • Malignancy
  • Malabsorption
    • Previous cholecystectomy
    • Chronic pancreatitis
    • Lactose intolerance
    • Coeliac disease
    • Short bowel syndrome
  • Drugs / iatrogenic
    • Antibiotics
    • Metformin
    • Colchicine
    • Laxatives
    • Chemotherapy
    • Radiotherapy
  • Endocrine
    • Hyperthyroidism
    • Diabetes – autonomic neuropathy
    • VIPoma
      • MEN1
    • Carcinoid syndrome
    • Zollinger-Ellison syndrome
  • Functional (IBS)

Relevant points in the history

  • Diarrhoea
    • How many times a day do you pass motion?
    • What does your stool look like?
    • Are you able to control yourself before you get to the toilet?
    • Do you have to wake up in the middle of the night to pass motion?
    • Does it get better or worse after you eat?
    • Is the stool difficult to flush away?
    • Is there any blood in your stool?
    • What is your usual bowel habit?
    • How has this been affecting your life?
  • Infective diarrhoea
    • Have you had a fever?
    • Do you have any tummy pain?
    • Do you feel nauseous?
    • Have you vomited?
    • Have you eaten anything unusual recently?
    • Have you attended any barbeques?
    • Is anyone else in your household down with the same symptoms?
    • Have you travelled anywhere recently?
    • HIV-associated (microsporidia, cryptosporidia, CMV colitis)
      • Are you sexually active?
      • How many sexual partners do you have?
      • Are they male, female or both?
      • What kind of sexual activity do you engage in?
      • Are you the receptive or insertive partner?
  • Inflammatory bowel disease
    • Have you ever had problems with diarrhoea before?
    • Do you have any tummy pain?
    • Does it come and go?
    • Do you have any mouth ulcers?
    • Do you have blood in your stools?
    • Do you feel there is mucus or pus in your stool?
    • Do you have any joint pains?
    • Have you ever been troubled by red or painful eyes?
  • Malignancy
    • Have you lost any weight?
    • Do you have any difficulty in swallowing?
    • Do you feel full very early on in a meal?
    • Have you noticed any blood in your stools?
    • Have you noticed any change in colour of your stools?
  • Malabsorption
    • Do you find your stool is very difficult to flush away?
    • Does it float on the water?
    • Has the smell of your stool changed recently?
    • Have you noticed any back pain?
    • Have you ever drunk any alcohol?
    • Do you feel tired all the time?
    • Does the diarrhoea get worse when you eat certain foods?
      • Lactose
      • Gluten
    • Have you ever needed surgery to remove your bowel?
  • Drugs / iatrogenic
    • Do you take any regular medicines?
    • Have the doses of any of these medicines changed?
    • Have you been given any antibiotics recently?
    • Have you ever taken colchicine for joint pains?
    • Have you ever needed radiotherapy to your bowel area?
    • Have you ever taken chemotherapy?
  • Endocrine
    • Hyperthyroidism
      • Do you feel unusually intolerant of the heat?
      • Do you feel your heart beating very fast at times?
      • Do you feel anxious easily?
      • Have you ever noticed any double vision?
    • Diabetes
      • Do you have diabetes?
      • Do you feel dizzy when getting up from a sitting position?
      • Have you noticed any trouble with passing urine?
      • Have you ever noticed any tingling in your hands or feet?
    • VIPoma
      • Do you have any weakness or muscle cramps?
      • Does anything run in the family?
      • Does anyone in your family have trouble with diarrhoea or stomach ulcers?
      • Have you noticed you are bumping into things more often than usual?
      • Do you feel thirsty a lot?
      • Do you need to go to the toilet to pass urine a lot?
    • Carcinoid
      • Have you ever noticed that your face is red?
      • Have you ever noticed a noisy sound when you breathe in or out?
    • Irritable bowel syndrome
      • Do you notice any tummy pain that gets better after you pass motion?
      • How are things in your life?
      • Do you feel stressed?

Examination

  • General
    • Pallor
    • Cachexia
    • Hydration
    • Exophthalmos
    • Divergent gaze
    • Tremor
  • Thyroid status
    • Pulse: rate and rhythm
    • Proptosis
    • Lid lag
    • Goitre
    • Complex ophthalmoplegia
    • Displaced apex beat
    • Lung bases for peripheral oedema
    • Pre-tibial myxoedema
  • Visual fields (pituitary tumour)
  • Pan-systolic murmur of tricuspid regurgitation (carcinoid syndrome)
  • Abdomen
    • Lymphadenopathy
    • Masses
    • Hepatomegaly
    • Distension – ascites
    • Bowel sounds
  • Offer digital rectal examination

Investigations

  • Full blood count looking for anaemia, leukocytosis in acute gastroenteritis
  • Renal function to look for acute kidney injury caused by dehydration
    • Hypokalaemia in chronic diarrhoea, severe in VIPoma
  • Liver function tests for malignancy metastasizing to liver
  • Thyroid function tests looking for raised T4, low TSH
  • HIV test
  • 24hour urine 5-hydroxyindolacetic acid for carcinoid syndrome
  • Serum gastrin for Zollinger-Ellison syndrome
  • Serum vasoactive intestinal peptide for VIPoma
  • Malabsorption
    • Faecal fat globules for malabsorption (increased in malabsorption)
    • Faecal elastase test (decreased in chronic pancreatitis)
    • IgA endomysial antibodies, tissue transglutaminase antibodies (coeliac disease)
  • Stool culture, Gram stain and microscopy for parasites
  • Colonoscopy to look for underlying malignancy, inflammatory bowel disease
  • Consider enteroscopy if serology for coeliac disease negative but history very suggestive
  • Consider computed tomography scan of the thorax, abdomen and pelvis to look for metastases

Management

  • Multidisciplinary team approach
  • Patient education
  • Infective diarrhoea
  • Crohn’s disease
    • Topical steroids for oral ulcers
    • Proton pump inhibitor for gastroduodenal disease
    • Acute flares of ileitis:
      • Antibiotics
      • 5-aminosalicylates
      • Glucocorticoids (hydrocortisone, prednisolone, budesonide) to induce remission
    • Maintenance therapy
      • 5-ASA (e.g. mesalazine)
      • If uncontrolled on 5-ASA alone
        • Azathioprine or the active metabolite 6-mercaptopurine
        • Methotrexate if azathioprine not tolerated
      • Failure of the above: biologics
        • Infliximab, adalimumab (anti-TNF)
        • Natalizumab, vedolizumab (anti-integrin)
  • Ulcerative colitis
    • Topical 5-ASA for proctitis / sigmoiditis
    • Topical steroids may be added to induce remission
    • Oral 5-ASA if not responding to topical therapy
    • Maintenance
      • Oral 5-ASA only if oral agents required for remission, or multiple exacerbations
      • May require oral glucocorticoids to prevent remission (steroid-dependent UC)
    • Fulminant UC (>10 stools / day, continuous bleeding, toxicity, fever – risk of megacolon, perforation)
      • NBM, parenteral nutrition if necessary
      • Decompression via NG tube
      • High-dose IV steroids
      • Cyclosporine or infliximab for induction of remission
      • Consider colectomy in patients who fail to respond to above, or toxic megacolon
  • Infective diarrhoea
    • Rehydrate
    • Usually self-limiting
    • Treat cultures if positive
    • Consider treatment in severe secretory diarrhoea
    • Ciprofloxacin 500mg BD will cover most enteric pathogens
  • Malabsorption
    • Treat diarrhoea: loperamide
    • Supplement fat-soluble vitamins if substantial steatorrhoea
    • Avoidance of gluten / lactose
    • Consider exogenous pancreatic lipase for chronic pancreatitis
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