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Summary for primary care

Diarrhoea—Adult's Assessment

Latest Guidance Updates

June 2023: a recommendation to ask about sexual history, particularly in men who have sex with men, was added to this topic in line with the British Association for Sexual Health and HIV (BASHH) United Kingdom national guideline for the management of sexually transmitted enteric infections 2023.

Overview

This Guidelines summary of NICE's Clinical Knowledge Summary (CKS) covers the assessment, investigation, and referral of adults with acute or chronic diarrhoea in primary care.

For background information, explanation of the basis for recommendations, and the complete set of recommendations, refer to the full CKS.

Reflecting on Your Learnings

Reflection is important for continuous learning and development, and a critical part of the revalidation process for UK healthcare professionals. Click here to access the Guidelines Reflection Record.

How Should I Assess a Person with Acute Diarrhoea?

  • Determine the onset, duration, frequency, and severity of symptoms.
  • Enquire about the presence of red flag symptoms:
    • Blood in the stool.
    • Recent hospital treatment or antibiotic treatment. For more information, see the CKS topic on Diarrhoea - antibiotic associated.
    • Weight loss.
    • Evidence of dehydration.
    • Nocturnal symptoms—organic cause more likely.
  • Also ask about sexual history (particularly in men who have sex with men) to exclude sexually transmitted enteric infection.
  • Attempt to ascertain the underlying cause. Assess for:
    • Quantity and character of stools (watery, fatty, containing blood or mucus).
    • Features suggesting infection, such as:
      • Fever.
      • Vomiting.
      • Recent contact with a person with diarrhoea.
      • Exposure to possible sources of enteric infection (for example, having eaten meals out, or recent farm or petting zoo visits).
      • Travel abroad—increases the likelihood of infection. Ask about potential exposures such as raw milk or untreated water.
      • Being in a higher risk group such as food handlers, nursing home residents, and recently hospitalized people.
    • Any new drugs, especially antibiotics or laxatives. For examples, see the section on causes of acute diarrhoea in the full CKS.
    • Stress or anxiety.
    • Abdominal pain, which is often present in inflammatory bowel disease, irritable bowel syndrome, and ischaemic colitis.
    • History of recent radiation treatment to the pelvis.
    • Factors increasing the risk of immunosuppression (for example, human immunodeficiency virus infection, long term steroid use, or chemotherapy).
    • Any surgery or medical conditions (for example, endocrine disease) accounting for the diarrhoea.
    • Diet and use of alcohol or substances such as sorbitol.
  • Assess for complications of diarrhoea, such as dehydration.
    • Features indicating dehydration include increased pulse rate, reduced skin turgor, dryness of mucous membranes, delayed capillary refill time, decreased urine output, hypotension (check for postural changes), and altered mental status. For more detail, see the section on clinical features of dehydration.
    • Also consider underlying conditions that may increase the risk of complications.
  • Perform an abdominal examination to assess for pain or tenderness, distension, mass, increased or decreased bowel sounds, or liver enlargement.
  • Consider a rectal examination to assess for rectal tenderness, stool consistency, and for blood, mucus, and possible malignancy.
  • If acute causes have been excluded and the person has features suggestive of an early presentation of a chronic cause, see the section on chronic diarrhoea in this summary.

Clinical Features of Dehydration

  • Mild dehydration
    • Lassitude.
    • Anorexia, nausea.
    • Light-headedness.
    • Postural hypotension.
    • Usually no signs.
  • Moderate dehydration
    • Apathy/tiredness.
    • Dizziness.
    • Nausea/headache.
    • Muscle cramps.
    • Pinched face.
    • Dry tongue or sunken eyes.
    • Reduced skin elasticity.
    • Postural hypotension.
    • Tachycardia.
    • Oliguria.
  • Severe dehydration
    • Profound apathy.
    • Weakness.
    • Confusion, leading to coma.
    • Shock.
    • Tachycardia.
    • Marked peripheral vasoconstriction.
    • Systolic blood pressure less than 90 mmHg.
    • Oliguria or anuria.

How Should I Investigate Acute Diarrhoea in Primary Care?

  • Send a faecal specimen for routine microbiology investigation if a person with diarrhoea has:
    • Symptoms/signs or a clinical indication:
      • The person is systemically unwell; needs hospital admission, and/or antibiotics.
      • There is blood or pus in the stool.
      • The person is immunocompromised.
      • The person has recently received antibiotics, a proton pump inhibitor (PPI) or been in hospital—also request specific testing for Clostridium difficile. For more information, see the CKS topic on Diarrhoea - antibiotic associated
      • Diarrhoea occurs after foreign travel—also request tests for ova, cysts, and parasites and state the countries visited on the form.
      • Amoebae, Giardia, or cryptosporidium are suspected, particularly if diarrhoea is persistent (2 weeks or more) or the person has travelled to an at-risk area.
      • There is a need to exclude infectious diarrhoea (for example severe abdominal pain, exacerbation of inflammatory bowel disease, or irritable bowel syndrome).
    • A public health indication:
      • Diarrhoea in high-risk people (for example food handlers, healthcare workers, elderly residents in care homes).
      • Suspected food poisoning (for example after a barbecue, restaurant meal, or eating eggs, chicken, or shellfish).
      • Outbreaks of diarrhoea in the family or community, when isolating the organism may help pinpoint the source of the outbreak.
      • Contacts of people infected with certain organisms, for example, Escherichia coli O157 or C. difficile, where there may be serious clinical sequelae to an infection.
      • Close household contacts of a person with Giardia infection.
  • For more information on how to send a stool sample (such as what information to include), see the section on sending a stool sample.
  • Consider blood tests if infection and the other causes of acute diarrhoea have been excluded and it is suspected that an episode of acute diarrhoea is due to a chronic cause.
    • See the section on investigations for chronic diarrhoea for advice on which blood tests to request.

Sending a Stool Sample

  • Send a single specimen (a quarter full specimen pot is the minimum needed for routine microbiology investigation). Only send loose stools as the laboratory will not examine formed stools. 
  • If diarrhoea occurs after exotic travel abroad, is recurrent, or prolonged, request ova, cysts, and parasites and give details of travel. Send three specimens a minimum of 2 days apart (ova, cysts, and parasites are shed intermittently).
  • Ensure that the following details are included on the request form:
    • Clinical features (for example fever; bloody stool; severe abdominal pain).
    • History of immunosuppression.
    • Food intake (for example shellfish).
    • Recent foreign travel (specify countries).
    • Recent antibiotic therapy, proton pump inhibitor therapy, or hospitalization (suggestive of Clostridium difficile infection).
    • Exposure to untreated water (suggestive of infection with protozoa).
    • Contact with other affected people, or an outbreak.
  • Repeat specimens are usually unnecessary, unless advised by a specialist (microbiologist or consultant in public health), or ova, cysts and parasites are suspected.

When Should I Admit or Refer a Person With Acute Diarrhoea?

  • Arrange emergency admission to hospital if:
    • The person is vomiting and unable to retain oral fluids, or
    • They have features of severe dehydration or shock (for more information, see the section on clinical features of dehydration). 
  • Other factors that influence the threshold for admission include (use clinical judgment):
    • Older age (people 60 years of age or older are more at risk of complications).
    • Home circumstances and level of support.
    • Fever.
    • Bloody diarrhoea.
    • Abdominal pain and tenderness.
    • Increased risk of poor outcome, for example:
      • Coexisting medical conditions—immunodeficiency, lack of stomach acid, inflammatory bowel disease, valvular heart disease, diabetes mellitus, renal impairment, rheumatoid disease, systemic lupus erythematosus.
      • Drugs—immunosuppressants or systemic steroids, proton pump inhibitors, angiotensin-converting enzyme inhibitors, diuretics.
  • Refer adults using a suspected cancer pathway referral (for an appointment within 2 weeks) for colorectal cancer if:
    • They are aged 40 and over with unexplained weight loss and abdominal pain, or
    • They are aged 50 and over with unexplained rectal bleeding, or
    • They are aged 60 and over with iron deficiency anaemia or changes in their bowel habit, or tests show occult blood in their faeces.
  • Consider a suspected cancer pathway referral (for an appointment within 2 weeks) for colorectal cancer in:
    • Adults with a rectal or abdominal mass.
    • Adults aged under 50 with rectal bleeding and any of the following unexplained symptoms or findings:
      • Abdominal pain.
      • Change in bowel habit.
      • Weight loss.
      • Iron-deficiency anaemia.
  • Refer if the diagnosis remains uncertain after a primary care assessment—if infection and the other common causes of acute diarrhoea have been excluded and it is suspected that an episode of acute diarrhoea is due to a chronic cause.

How Should I Assess a Person with Chronic Diarrhoea?

  • Determine the duration, frequency, pattern, and severity of symptoms.
  • Ask about and look for 'red flag' indicators (symptoms and/or features that may be caused by another condition that need referral or further investigation). These include:
    • Unexplained weight loss.
    • Unexplained rectal bleeding.
    • Persistent blood in the stool.
    • Abdominal mass.
    • Rectal mass.
    • Severe abdominal pain.
    • Iron deficiency anaemia.
    • Raised inflammatory markers (may indicate inflammatory bowel disease).
    • Nocturnal or continuous diarrhoea or both (suggestive of an organic rather than functional disorder).
    • Fever, tachycardia, hypotension, dehydration.
  • Look for other features suggestive of an underlying cause, including:
    • Travel abroad—consider an infective cause, especially Giardia.
    • Laxative use (including for treatment of hepatic encephalopathy).
    • Other drugs. For examples, see the section on chronic causes of diarrhoea in the full CKS.
      • Recent use of an antibiotic or proton pump inhibitor is associated with Clostridium difficile infection.
    • Chronic fatty diarrhoea—suggests fat maldigestion (for example pancreatic insufficiency) or fat malabsorption (for example coeliac disease).
    • Previous abdominal surgery—suspect bile acid diarrhoea if the person has a history of cholecystectomy or ileal resection.
    • Family history of coeliac disease or inflammatory bowel disease.
    • Diet and relationship of symptoms to eating—lactose intolerance is suggested if symptoms are worsened by dairy products; diarrhoea may be due to consumption of caffeine or food additives, such as sorbitol.
    • Excessive alcohol intake—can cause a toxic effect on intestinal epithelium or rapid gut transit.
    • Abdominal pain—may indicate coeliac disease, Crohn's disease, or malignancy.
    • Weight loss, anxiety, palpitations, tremor—consider hyperthyroidism.
    • Lifelong history of constipation—consider impaction with overflow diarrhoea.
    • Immunocompromised person—consider opportunistic infection with parasites (for example Giardia, Cryptosporidium, Cyclospora).
    • Features of systemic disease (such as thyrotoxicosis, diabetes, adrenal insufficiency).
    • Systemic illness affecting gastrointestinal motility (for example scleroderma, diabetes mellitus); history of inflammatory bowel disease; previous gastrointestinal surgery with risk of—consider small intestinal bacterial overgrowth (SIBO).
    • Rashes (for example pyoderma gangrenosum or erythema nodosum in inflammatory bowel disease; hyperpigmentation in Addison's disease; dermatitis herpetiformis in coeliac disease).
  • Assess for features that indicate a diagnosis of irritable bowel syndrome.
  • Perform an abdominal examination, looking for distension, an abdominal mass, organomegaly, or tenderness.
  • Do a digital rectal examination, provided this is acceptable to the person being examined. Note any faecal leakage, haemorrhoids, type of stool, and presence of blood.

How Should I Investigate Chronic Diarrhoea in Primary Care?

  • Tailor investigations to the individual, and if necessary, refer for further investigation.
  • Request the following blood tests in all people with chronic diarrhoea:
    • Full blood count—to detect anaemia.
    • Urea and electrolytes.
    • Liver function tests, including albumin level.
    • Calcium.
    • Vitamin B12 and red blood cell folate.
    • Iron status (ferritin).
    • Thyroid function tests.
    • ESR (erythrocyte sedimentation rate) and CRP (C-reactive protein). 
    • Testing for coeliac disease—immunoglobulin A (IgA), and IgA tissue transglutaminase (tTG), or IgA endomysial antibody (EMA).
      • Note that antibodies usually will become negative when a person is on a gluten-free diet, so the test should be carried out when they are eating a diet containing gluten.
      • For more information, see the CKS topic on Coeliac disease
  • Consider CA125 testing if there are symptoms suggestive of ovarian cancer. For more information, see the CKS topic on Ovarian cancer.
  • Consider HIV serology if underlying immunodeficiency is suspected. For more information see the CKS topic on HIV infection and AIDS
  • Consider sending stool for:
    • Routine microbiology investigation and examination for ova, cysts and parasites, if an infectious cause is suspected or there is a history of exotic foreign travel.
      • Send three specimens at least 2 days apart, as ova, cysts, and parasites are shed intermittently.
      • For more information on how to send a stool sample, see the recommendations on sending a stool sample in the section on acute diarrhoea.
    • Clostridium difficile testing, particularly if the person has recently been admitted to hospital or treated with antibiotics or a proton pump inhibitor, or if a previous episode has resolved and the symptoms have recurred. For more information, see the CKS topic on Diarrhoea - antibiotic associated.
    • Faecal calprotectin testing to help differentiate between irritable bowel syndrome and inflammatory bowel disease in people under the age of 40 years if specialist assessment is being considered and cancer is not suspected
      • Note that faecal calprotectin should not be used for people:
        • With new onset rectal bleeding or bloody diarrhoea.
        • In whom there is a need to rule out cancer. 
      • For more information, see the CKS topics on Crohn's disease and Ulcerative colitis
    • Testing for blood in the faeces in people with symptoms suggestive of colorectal cancer who do not meet suspected cancer referral pathway criteria.

When Should I Refer a Person with Chronic Diarrhoea?

  • Refer adults using a suspected cancer pathway referral (for an appointment within 2 weeks) for colorectal cancer if:
    • They are aged 40 and over with unexplained weight loss and abdominal pain, or
    • They are aged 50 and over with unexplained rectal bleeding, or
    • They are aged 60 and over with iron deficiency anaemia or changes in their bowel habit, or tests show occult blood in their faeces.
  • Consider a suspected cancer pathway referral (for an appointment within 2 weeks) for colorectal cancer in: 
    • Adults with a rectal or abdominal mass.
    • Adults aged under 50 with rectal bleeding and any of the following unexplained symptoms or findings:
      • Abdominal pain.
      • Change in bowel habit.
      • Weight loss.
      • Iron-deficiency anaemia.
  • Refer for further assessment and management if:
    • History, examination, and blood test results suggest any of the following:
      • Coeliac disease. For more information, see the CKS topic on Coeliac disease.
      • Crohn's disease. For more information, see the CKS topic on Crohn's disease
      • Ulcerative colitis. For more information, see the CKS topic on Ulcerative colitis
      • Bile acid diarrhoea.
      • Microscopic colitis.
      • Malabsorption.
    • A person less than 40 years of age does not have typical symptoms of functional bowel disorder and/or has severe symptoms and documented diarrhoea. 
    • The diagnosis is uncertain.

References


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