Chapter 44: Diarrhoea

Diarrhoea is defined as an intestinal disorder characterised by abnormal frequency and liquidity of faecal evacuations.

Acute self-limiting diarrhoea, which is very common and frequently not seen by the medical practitioner, is usually infective and mild, and resolves within days. In Australia most infective cases are viral. The causes of diarrhoea are numerous, thus making a detailed history and examination very important in leading to the diagnosis. ‘Chronic’ diarrhoea is that lasting at least 4–6 weeks. Important causes are presented in FIGURE 44.1.

The terminology for acute infective diarrhoea can be confusing. A simple classification is:

• vomiting and diarrhoea = gastroenteritis

• diarrhoea (only) = enteritis

A summary of the diagnostic strategy model is presented in TABLE 44.1.

Probability diagnosis

Acute diarrhoea

Common causes are:

• gastroenteritis/enteritis:

  • – bacterial: Salmonella sp., Campylobacter jejuni, Shigella sp., enteropathic Escherichia coli, Staphylococcus aureus (food poisoning)

  • – viral: rotavirus (50% of children hospital admissions¹), norovirus, astrovirus, adenovirus

• dietary indiscretions (e.g. binge eating)

• antibiotic reactions

Chronic diarrhoea

Irritable bowel syndrome was the commonest cause of chronic diarrhoea in a UK study.¹

Drug reactions are also important. These include ingestion of laxatives, osmotic agents such as lactose and sorbitol in chewing gum, alcohol, antibiotics, thyroxine and others.

Acute gastroenteritis that persists into a chronic phase is relatively common, especially in travellers returning from overseas. Important considerations are Giardia lamblia, C. difficile, Yersinia, Entamoeba histolytica, Cryptosporidium and HIV infection.

Serious disorders not to be missed

Colorectal carcinoma must be considered with persistent diarrhoea, especially if of insidious onset.

AIDS due to symptomatic HIV infection needs consideration, especially in those at risk. The serious infectious disorders that can affect international travellers, such as cholera, typhoid, paratyphoid and amoebiasis, should also be kept in mind.

In children, coeliac disease and cystic fibrosis can present as chronic diarrhoea, while intussusception, although not causing true diarrhoea, can present as loose, redcurrant jelly-like stools and should not be misdiagnosed (as gastroenteritis). Appendicitis must also be considered in the onset of acute diarrhoea and vomiting.

Infection with enterohaemorrhagic strains of E. coli (e.g. O157:H7, O111:H8) may lead to the haemolytic uraemic syndrome or thrombotic thrombocytopenic purpura, particularly in children. What appears to be simple enteritis can eventuate to be fatal. If suspected, avoid giving antibiotics.

Clue: Think of it with atypical gastroenteritis and bloody diarrhoea. Avoid antibiotics.

Death cap mushroom (the world’s most lethal)—Amanita phalloides (FIGURE 44.2)—causes severe gastroenteritis followed by delayed hepatic failure and AKF.

Pitfalls

There are many traps in evaluating the patient with diarrhoea, including drug ingestion, especially vitamin C (sodium ascorbate powder), which causes diarrhoea. Faecal impaction with spurious diarrhoea is an age-old pitfall, as is lactase deficiency, which may go undiagnosed for many years. In recent times infection with G. lamblia may smoulder on for months with watery, offensive stools before diagnosis.

General pitfalls

• Not considering acute appendicitis in acute diarrhoea—can be retrocaecal or pelvic appendicitis

• Missing faecal impaction with spurious diarrhoea

• Failing to perform a rectal examination

• Failing to consider acute ischaemic colitis in an elderly patient with the acute onset of bloody diarrhoea stools (following sudden abdominal pain in preceding 24 hours)

Seven masquerades checklist

The significant masquerades include diabetes, when an autonomic neuropathy may cause alternating bouts of constipation and diarrhoea, thyrotoxicosis and drugs. Drugs that can cause diarrhoea are summarised in TABLE 44.2.

Pseudomembranous colitis (antibiotic-associated diarrhoea)²

This potentially fatal colitis can be caused by the use of any antibiotic, especially clindamycin, lincomycin, ampicillin and the cephalosporins (an exception is vancomycin). It is usually due to an overgrowth of C. difficile, which produces a toxin that causes specific inflammatory lesions, sometimes with a pseudomembrane. It may occur, uncommonly, without antibiotic usage.

Clinical features

• Profuse, watery diarrhoea

• Abdominal cramping and tenesmus ± fever

• Within 2 days of taking antibiotic (can start up to 4 to 6 weeks after usage)

• Persists 2 weeks (up to 6) after ceasing antibiotic

Diagnosed by characteristic lesions on sigmoidoscopy and a tissue culture assay and/or PCR for C. difficile toxin.

Treatment²

• Cease antibiotic

• Need hygiene measures to prevent spread

• Mild to moderate: metronidazole 400 mg (o) tds for 10 days

• Severe: vancomycin 125 mg (o) qid for 10 days (in consultation with specialist). Beware of toxic megacolon.

Psychogenic considerations

Anxiety and stress can cause looseness of the bowel. The irritable bowel syndrome, which is a very common condition, may reflect underlying psychological factors and most patients find that the symptoms are exacerbated by stress. Look for evidence of depression.

In children chronic diarrhoea can occur with the so-called ‘maternal deprivation syndrome’, characterised by growth and developmental retardation due to adverse psychosocial factors.

History

As always, the history is the key to the diagnosis. First establish what the patient means by the term ‘diarrhoea’, his or her normal pattern and how the presenting problem varies from normal.

It is important to analyse the nature of the stools, the frequency of diarrhoea, associated symptoms, including abdominal pain, and constitutional symptoms, such as fever. Food intake in the past 72 hours and recent travel abroad may give a clue to acute gastroenteritis or food poisoning (an acute, self-limiting illness of diarrhoea and vomiting). The difference between food poisoning and infective gastroenteritis is presented in TABLE 44.3. However, there can be an overlap of features from a specific organism and the exercise may be semantic, but it may provide a clue to food-borne causation. A summary of non-microbial food poisoning is presented in TABLE 44.4.

A drug history is relevant, as is a family history of diarrhoea, which may be significant for coeliac disease, Crohn disease and cystic fibrosis.

Enquire sensitively about sexual activity. Patients at risk from HIV infection should be discreetly evaluated.

Key questions

• Where did you eat in the 24 hours before the diarrhoea started?

• What food did you eat during this time?

• Did you have chicken or seafood recently? (Chicken may be contaminated with Salmonella or Campylobacter and seafood with Vibrio parahaemolyticus.)

• Did any other people get the same problem?

• Have you travelled overseas recently? Where?

• Have you noticed any blood or mucus in your motions?

• Have you had any previous attacks?

• Have you noticed fever, weakness or other symptoms?

• Have you noticed any blood or mucus in the motion?

• Have you travelled overseas recently? Where?

• Do you have pain and is it relieved by opening your bowels or passing wind?

• Does anyone else in your family have diarrhoea?

• Have you had any operations on your abdomen recently?

• What medications are you taking?

• Are you taking antibiotics?

• Do you take vitamin C for your health?

• Do you take laxatives?

• How much alcohol do you drink? Fruit juice?

• How much milk do you drink?

• What about thick shakes, ice-cream and yoghurt?

• Do you get clammy or shaky, or have you lost weight?

• Have you had trouble with pain in your joints, back pain, eye trouble or mouth ulceration?

• Do you have trouble flushing your motions down the toilet?

• Do you get diarrhoea during the night?

• Are you under a lot of stress?

Significance of symptoms

Central colicky abdominal pain indicates involvement of the small bowel, while lower abdominal pain points to the large bowel.

If small volume, consider inflammation or carcinoma of colon; if large volume, consider laxative abuse and malabsorption.

If there is profuse bright red bleeding, consider diverticulitis or carcinoma of colon, and if small amounts with mucus or mucopus consider inflammatory bowel disorder. The presence of blood in the stools excludes functional bowel disorder. Diarrhoea at night suggests organic disease. In steatorrhoea the stools are distinctively pale, greasy, offensive, floating and difficult to flush. It is exacerbated by fatty foods.

‘Rice water’ stool is characteristic of cholera and ‘pea soup’ stool of typhoid fever.

Examination

The extent of the examination depends on the nature of the presenting problem. If it is acute, profuse and associated with vomiting, especially in a child, the examination needs to be general to assess the effects of fluid, electrolyte and nutritional loss. An infant’s life is in danger from severe gastroenteritis and this assessment is a priority. The general nutritional and electrolyte assessment is also relevant in chronic diarrhoea with malabsorption, and this includes looking for evidence of muscle weakness (e.g. hypokalaemia, hypomagnesaemia, tetany [hypocalcaemia], bruising [vitamin K loss]).

The examination should also focus on the abdomen (systematic palpation), the rectum and the skin. Possible helpful signs are included in FIGURE 44.3.

The stool

Ideally the stool should be examined. The consistency of the stool as an aid to diagnosis^2,4 is summarised in TABLE 44.5, the features of the stool in TABLE 44.6, and the characteristics that distinguish between small and large bowel diarrhoea¹ are presented in TABLE 44.7. Note the presence of blood or mucus or steatorrhoea.

Consider: inflammatory bowel disease, colonic polyps, carcinoma, infective especially Shigella, Salmonella, Campylobacter, E. coli, amoebiasis, colitis (pseudomembranous, ischaemic).

Investigations³

The following list includes a range of tests that may be required. Appropriate tests should be judiciously selected and in some instances, such as acute self-limiting diarrhoea, no investigations are necessary.

• Stool tests:

  • – microscopy for parasites and red and white cells (warm specimen for amoebiasis)

  • – cultures: may need special requests for Campylobacter sp., C. difficile and toxin, Yersinia sp., Cryptosporidium sp., Aeromonas sp. (stools must be collected fresh on three occasions)

• Blood tests: haemoglobin; MCV, WCC, ESR, iron, ferritin, folate, vitamin B12, calcium, electrolytes, thyroid function, HIV tests

• Antibody tests, total IgA (e.g. IgA anti-endomysial, IgA transglutaminase for coeliac disease); PCR tests (where applicable)

• Haemagglutination tests for amoebiasis

• C. difficile tissue culture assay

• Malabsorption studies

• Endoscopy:

  • – proctosigmoidoscopy

  • – flexible sigmoidoscopy/colonoscopy (with biopsy)

  • – small bowel biopsy (coeliac disease)

• Radiology:

  • – plain X-ray abdomen—of limited value

  • – small bowel enema

  • – barium enema, especially double contrast

Note: HIV patients should be investigated in specialist centres.

Principles of treatment³

When an underlying cause of diarrhoea can be identified, apart from some common infections, management should be directed at that cause. There are a few situations in which the causative bacterial or parasitic pathogen requires specific treatment, for example, giardiasis. The management is determined by the nature of the pathogen and the severity of the illness.

However, in Australia most infective cases are viral. The basic principle therefore is to achieve and maintain adequate hydration until the illness resolves. In adults and children oral rehydration is indicated unless there is evidence of impending circulatory ‘shock’ demanding intravenous therapy. Oral rehydration solution containing sodium, potassium and glucose should be considered for patients with mild to moderate dehydration. Adults should drink 2 to 3 L of the solution in 24 hours. Normal food intake may start after rehydration.

In general, treatment should not be directed specifically at altering the frequency and consistency of the stools. The antimotility drugs (loperamide, diphenoxylate and codeine) have a role restricted to short-term control of symptoms in adults during periods of significant social inconvenience, such as travel. It must be emphasised that antimotility drugs are never indicated for management of acute diarrhoea in infants and children.⁵

The traditional absorbent agents, such as kaolin/pectin mixtures, activated charcoal and other mineral clays, have not been shown to be of value and may interfere with absorption of other drugs. They should not be used.

Specific antibiotics are reserved for the treatment of giardiasis, amoebiasis, antibiotic-associated diarrhoea, cholera and typhoid. Although antibiotics are usually unnecessary, in most cases they may be indicated for severe cases of Campylobacter enteritis, Salmonella enteritis, shigellosis and traveller’s diarrhoea. Lactobacillus has been shown to reduce the duration of diarrhoea in rotavirus-related enteritis and antibiotic-associated diarrhoea.

Diagnostic triads for diarrhoea

It is important to distinguish the steatorrhoea of various malabsorption syndromes from diarrhoea. Important causes are presented in TABLE 44.8.

The common causes are coeliac disease, chronic pancreatitis and postgastrectomy.

Clinical features

• Bulky, pale, offensive, frothy, greasy stools

• Stools difficult to flush down toilet

• Weight loss

• Prominent abdomen

• Failure to thrive (in infants)

• Increased faecal fat

• Signs of multiple vitamin deficiencies (e.g. A, D, E, K)

• Sore tongue (glossitis)

• Hypochromic or megaloblastic anaemia (possible)

Refer for specific investigations (e.g. FBE, barium studies, small bowel biopsy, faecal fat [>21 g/3 days]).

Coeliac disease²

Synonyms: coeliac sprue, gluten-sensitive enteropathy.

Note: It can appear at any age; refer to coeliac disease in children (see later in chapter).

It is widely underdiagnosed because most patients present with non-GIT symptoms, such as tiredness.

There is a genetic factor in this autoimmune disorder with a 1 in 10 chance if a first-degree relative is affected. Consider screening under 2 years if there is such an association.

Clinical features

• Classic tetrad: diarrhoea, weight loss, iron/folate deficiency, abdominal bloating

• Malaise, lethargy

• Flatulence

• Mouth ulceration

• Diarrhoea with constipation (alternating)

• Pale and thin patient

• No subcutaneous fat

• Elevated faecal fat

• Characteristic duodenal biopsy: villous atrophy (key test)

• Total IgA level

• IgA antigliadin antibodies (screening—limited)

• IgA anti-endomysial antibodies (>90% sensitivity and specificity)

• IgA transglutaminase antibodies (>90% sensitivity and specificity)

Associations

• Iron-deficiency anaemia

• Type 1 diabetes

• Pernicious anaemia

• Primary biliary cirrhosis

• Subfertility

• Malignancy, especially lymphoma

• Dermatitis herpetiformis

• IgA deficiency

• Autoimmune thyroid disease

• Osteoporosis

• Neurological (e.g. seizures, ataxia, peripheral neuropathy)

• Down syndrome

Management

• Diet control: high complex carbohydrate and protein, low fat, gluten-free (no wheat, barley, rye and oats)

• Treat specific vitamin and mineral deficiencies

• Give pneumococcal vaccination (increased risk of pneumococcus sepsis)

Avoid foods containing gluten either as an obvious component (e.g. flour, bread, oatmeal), or as a hidden ingredient (e.g. dessert mix, stock cube).

Forbidden foods include:

• standard bread, pasta, crispbreads, flour

• standard biscuits and cakes

• breakfast cereals made with wheat or oats

• oatmeal, wheat bran, barley/barley water

• ‘battered’ or breadcrumbed fish, etc.

• meat and fruit pies

• most stock cubes and gravy mixes

Whipple disease

This is a rare malabsorption disorder usually affecting white males. It is caused by the bacillus Tropheryma whipplei. It may involve the heart, lungs and CNS.

Clinical features

• Males >40 years

• Chronic diarrhoea (steatorrhoea)

• Arthralgia (migratory seronegative arthropathy mainly of peripheral joints)

• Weight loss

• Lymphadenopathy

• ± Fever

Diagnosis

• PCR for T. whipplei

• Jejunal biopsy—stunted villi

Treatment

IV ceftriaxone for 2 weeks then cotrimoxazole or tetracycline for up to 12 months

This produces a dramatic improvement.

The older the patient, the more likely a late onset of symptoms that reflect serious underlying organic disease, especially malignancy. Colorectal cancer needs special consideration. The older the patient, especially the bedridden elderly patient, the more likely the presentation of faecal impaction with spurious diarrhoea. The possibility of drug interactions, including digoxin, should also be considered. Ischaemic colitis must be considered in an elderly patient.

Ischaemic colitis

This is due to atheromatous occlusion of mesenteric vessels (low blood flow) (see CHAPTER 34).

Clinical features

Clinical features include:

• sharp abdominal pain in an elderly patient with bloody diarrhoea (low blood flow)

  or

• periumbilical pain and diarrhoea about 15–30 minutes after eating

• maybe loud bruits over central abdomen

• other evidence of generalised atherosclerosis

• barium enema shows ‘thumb printing’ sign due to submucosal oedema

• the definitive test is aortography and selective angiography of mesenteric vessels

• most episodes resolve—may be followed by a stricture

The commonest cause of diarrhoea in children is acute infective gastroenteritis, but there are certain conditions that develop in childhood and infancy and require special attention. The presentation of small amounts of redcurrant jelly-like stool with intussusception should also be kept in mind. Of the many causes only a few are commonly seen. The two commonest causes are infective gastroenteritis and antibiotic-induced diarrhoea.

Important causes of diarrhoea in children are:

• infective gastroenteritis

• antibiotics

• overfeeding (loose stools in newborn)

• dietary indiscretions

• toddler’s diarrhoea

• sugar (carbohydrate) intolerance

• food allergies (e.g. milk, soy bean, wheat, eggs)

• maternal deprivation

• malabsorption states: cystic fibrosis, coeliac disease

Note: Exclude surgical emergencies (e.g. acute appendicitis), infections (e.g. pneumonia), septicaemia, otitis media <5 years.

Acute gastroenteritis

Note: Dehydration from gastroenteritis is an important cause of death, particularly in obese infants (especially if vomiting accompanies the diarrhoea).

Definition

It is an illness of acute onset, of less than 10 days’ duration associated with fever, diarrhoea and/or vomiting, where there is no other evident cause for the symptoms.⁵

Causes

• Mainly rotavirus (developed countries) and adenovirus: viruses account for about 80%

• Bacterial: C. jejuni and Salmonella sp. (two commonest), E. coli and Shigella sp.

• Protozoal: G. lamblia, E. histolytica, Cryptosporidium

• Food poisoning—staphylococcal toxin

Differential diagnoses. These include septicaemia, urinary tract infection, intussusception, appendicitis, pelvic abscess, partial bowel obstruction, diabetes mellitus and antibiotic reaction⁴ (see TABLE 44.9).

Symptoms

• Anorexia, nausea, poor feeding, vomiting, fever, diarrhoea (fever and vomiting may be absent)

• Fluid stools (often watery) 10–20 per day

• Crying—due to pain, hunger, thirst or nausea

• Bleeding—uncommon (usually bacterial)

• Anal soreness

Viral indication: large volume, watery, typically lasts 2–3 days, systemic symptoms uncommon.

Bacterial indication: small motions, blood, mucus, abdominal pain and tenesmus.

Dehydration: must be assessed (see TABLE 44.10).

Complications:

• febrile convulsions

• sugar (lactose) intolerance (common)

• septicaemia, especially Salmonella

Management

Management is based on the assessment and correction of fluid and electrolyte loss.^5,6 Since dehydration is usually isotonic with equivalent loss of fluid and electrolytes, serum electrolytes will be normal.

Note: The most accurate way to monitor dehydration is to weigh the child, preferably without clothes, on the same scale each time. However, the easiest is clinical assessment (e.g. vomiting, no urine, lethargy and thirst).

• Drugs: antidiarrhoeals, anti-emetics and antibiotics

• Lemonade or similar sugary soft drink: osmotic load too high, can use if diluted 1 part to 4 parts water but sugar may be poorly tolerated

• Treat at home—if family can cope, vomiting is not a problem and no dehydration.

• Admit to hospital—if dehydration or persisting vomiting or family cannot cope; also infants <6 months and high-risk patients.

If applicable, remove child from day care or school and keep away from food preparation areas. Advise about hygiene, including handwashing and napkin disposal. If children are not dehydrated, encourage eating and drinking as tolerated.

• Give small amounts of fluids often

• Start solids after 24 hours

• Continue breastfeeding (should be increased in frequency, e.g. hourly)

  or

• Continue formula feeding if tolerated or resume it after 24 hours.

• Consider stool culture and test for rotavirus for symptoms that persist and worsen

Give fluids, a little at a time and often (e.g. 5 mL every 1–2 minutes by spoon or syringe or 50 mL every 15 minutes if vomiting a lot). A good method is to give 200 mL (about 1 cup) of fluid every time a watery stool is passed or a big vomit occurs.

The ideal fluid is Gastrolyte or Repalyte (new formulation). Other suitable oral rehydration preparations are WHO-recommended solutions Electrolade and Glucolyte.

A new product is Hydralyte paediatric rehydration, which is a solution as an ‘ice-block’ formulation:

• children 1–2 years—one ‘ice-block’ per hour

• older children—as often as desired.

Warning: Do not use straight lemonade or mix up Gastrolyte with lemonade or fluids other than water.

Method of assessing fluid requirements³

• Fluid loss (mL) = % dehydration × body weight (kg) × 10

• Maintenance (mL/kg/24 h): 1–3 mo: 120 mL; 4–12 mo: 100 mL; >12 mo: 80 mL

• Allow for continuing loss.

  Example: 8 month 10 kg child with 5% dehydration:

  • Fluid loss = 5 × 10 × 10 = 500 mL

  • Maintenance = 100 × 10 = 1000 mL

  • Total 24-hour requirement (min.) = 1500 mL

  • Approximate average hourly requirement = 60 mL

• Aim to give more (replace fluid loss) in the first 6 hours.

• Rule of thumb: give 100 mL/kg (infants) and 50 mL/kg (older children) in first 6 hours.

Reintroduce your baby’s milk or formula diluted to half strength (i.e. mix equal quantities of milk or formula and water). Their normal food can be continued but do not worry that your child is not eating food. Solids can be commenced after 24 hours. Best to start with bread, plain biscuits, jelly, stewed apple, rice, porridge or non-fat potato chips. Avoid fatty foods, fried foods, raw vegetables and fruit, and wholegrain bread.

Increase milk to normal strength and gradually continue reintroduction to usual diet.

Breastfeeding. If your baby is not vomiting, continue breastfeeding but offer extra fluids (preferably Gastrolyte) between feeds. If vomiting is a problem, express breast milk for the time being while you follow the oral fluid program.

Note: Watch for lactose intolerance as a sequela—explosive diarrhoea after introducing formula. Replace with a lactose-free formula.

If acute invasive or persistent Salmonella are present, give antibiotics (ciprofloxacin or azithromycin).

Sugar intolerance

Synonyms: carbohydrate intolerance, lactose intolerance.

The commonest offending sugar is lactose.

Diarrhoea often follows acute gastroenteritis when milk is reintroduced into the diet (some recommend waiting for 2 weeks). Stools may be watery, frothy, smell like vinegar and tend to excoriate the buttocks. They contain sugar. Exclude giardiasis.

A simple test follows.

• Line the napkin with thin plastic and collect fluid stool.

• Mix 5 drops of liquid stool with 10 drops of water and add a Clinitest tablet (detects lactose and glucose but not sucrose).

• A positive result indicates sugar intolerance.

Diagnosis: lactose breath hydrogen test.

Treatment

• Remove the offending sugar from the diet.

• Use milk preparations in which the lactose has been split to glucose and galactose by enzymes, or use soy protein.

Note: Most milk allergies improve with age.

Toddler’s diarrhoea (‘cradle crap’)

A clinical syndrome of loose, bulky, non-offensive stools with fragments of undigested food in a well, thriving child. The onset is usually between 8 and 20 months. Associated with high fructose intake (fruit juice diarrhoea).

Diagnosis by exclusion; treatment by dietary adjustment.

Cow’s milk protein intolerance⁷

This is not as common as lactose intolerance. Diarrhoea is related to taking a cow’s milk formula and relieved when it is withdrawn.

Allergic responses to cow’s milk protein may result in a rapid or delayed onset of symptoms. Delayed onset may be more difficult to diagnose, presenting with diarrhoea, malabsorption or failure to thrive.

It is diagnosed by unequivocal reproducible reactions to elimination and challenge. If diagnosed, remove cow’s milk from the diet and replace with either soy milk, a hydrolysed or an elemental formula (see CHAPTER 80).

Inflammatory bowel disorders

These disorders, which include Crohn disease and ulcerative colitis, can occur in childhood. A high index of suspicion is necessary to make an early diagnosis. Approximately 5% of cases of chronic ulcerative colitis have their onset in childhood.⁵

Chronic enteric infection

Responsible organisms include Salmonella sp., Campylobacter, Yersinia, G. lamblia and E. histolytica. With persistent diarrhoea, it is important to obtain microscopy of faeces and aerobic and anaerobic stool cultures. G. lamblia infestation is not an uncommon finding and may be associated with malabsorption, especially of carbohydrate and fat. Giardiasis can mimic coeliac disease.

Coeliac disease

(See earlier in chapter.)

Clinical features in childhood:

• usually presents at 9–18 months, but any age

• previously thriving infant

• anorexia, lethargy, irritability

• failure to thrive

• malabsorption—abdominal distension

• offensive frequent stools

Diagnosis: duodenal biopsy (definitive).

Treatment: remove gluten from diet.

Cystic fibrosis

Cystic fibrosis, which presents in infancy, is the commonest of all inherited disorders (1 per 2500 live births). Refer to CHAPTER 18.

Features

• Invariably a self-limiting problem (1–3 days)

• Abdominal cramps

• Possible constitutional symptoms (e.g. fever, malaise, nausea, vomiting)

• Other meal-sharers affected → food poisoning

• Consider dehydration, especially in the elderly

• Consider possibility of enteric fever

Traveller’s diarrhoea

The symptoms are usually as above, but very severe diarrhoea, especially if associated with blood or mucus, may be a feature of a more serious bowel infection such as amoebiasis. Possible causes of diarrhoeal illness are presented in TABLE 14.1, in CHAPTER 14. Most traveller’s diarrhoea is caused by E. coli, which produces a watery diarrhoea within 14 days of arrival in a foreign country. (For specific treatment refer to the section on Traveller’s diarrhoea in CHAPTER 14.)

Persistent traveller’s diarrhoea

Any traveller with persistent diarrhoea after visiting less developed countries, especially India and China, may have a protozoal infection such as amoebiasis or giardiasis.

If there is a fever and blood or mucus in the stools, suspect amoebiasis. Giardiasis is characterised by abdominal cramps, flatulence and bubbly, foul-smelling diarrhoea.

• Maintenance of hydration:

  • Antiemetic injection (for severe vomiting) prochlorperazine IM, statim

  • or

  • metoclopramide IV, statim

• Antidiarrhoeal preparations:

  • (avoid if possible: loperamide preferred)

  • loperamide (Imodium) 2 caps statim then 1 after each unformed stool (max: 8 caps/day)

  • or

  • diphenoxylate with atropine (Lomotil) 2 tabs statim then 1–2 (o) 8-hourly

General advice to patient

Your bowel needs a rest and so do you. It is best to reduce your normal activities until the diarrhoea has stopped.

Eat as normally as possible but drink small amounts of clear fluids such as water, tea, lemonade and yeast extract (e.g. Marmite). Then eat low-fat foods such as stewed apples, rice (boiled in water), soups, poultry, boiled potatoes, mashed vegetables, dry toast or bread, biscuits, most canned fruits, jam, honey, jelly, dried skim milk or condensed milk (reconstituted with water).

At first, avoid alcohol, coffee, strong tea, fatty foods, fried foods, spicy foods, raw vegetables, raw fruit (especially with hard skins), Chinese food, wholegrain cereals and cigarette smoking.

On the third day introduce dairy produce, such as a small amount of milk in tea or coffee and a little butter or margarine on toast. Add also lean meat and fish (either grilled or steamed).

Treatment (antimicrobial drugs)^2,8

Bacterial diarrhoea in adults and older children is usually self-limiting and does not require antibiotic treatment (they may be used to shorten the course of a persistent infection). Campylobacter, Salmonella, Shigella and E. coli are the most common causes. As a rule, use oral rehydration solution 2–3 L orally over 24 hours if mild to moderate dehydration. If severe, intravenous rehydration with N saline is recommended.

It is advisable not to use antimicrobials except where the following specific organisms are identified. The drugs should be selected initially from the list below or modified according to the results of culture and sensitivity tests.³ Only treat if symptoms have persisted for more than 48 hours. Adult doses are shown for the following specific enteric infections based on faecal culture. Recommended empirical therapy is ciprofloxacin or norfloxacin.

• cotrimoxazole (double strength) 1 tab (o) 12-hourly for 5 days: use in children (children’s doses)

• or

• norfloxacin 400 mg (o) 12-hourly for 5 days (preferred for adults)

• or

• ciprofloxacin 500 mg (o) bd for 5 days

This protozoal infestation is often misdiagnosed. It should be considered for a persistent profuse, watery, bubbly, offensive diarrhoea (see CHAPTER 15).

• tinidazole 2 g (o), single dose (may need repeat)

• or

• metronidazole 400 mg (o) tds for 7 days

• (in children: 30 mg/kg/day [to max. 1.2 g/day] as single daily dose for 3 days)

Antibiotics are not generally advisable, but if severe or prolonged use:

• ciprofloxacin 500 mg (o) bd for 5–7 days

• or

• azithromycin 1 g (o) day, then 500 mg for 6 days

• or

• ceftriaxone IV or ciprofloxacin IV if oral therapy not tolerated

Note: Salmonella is a notifiable disease; infants under 15 months are at risk of invasive Salmonella infection.

A zoonosis that is usually self-limiting.

Antibiotic therapy indicated in severe or prolonged cases:

• azithromycin 500 mg (o) 12-hourly for 3 days

• or

• ciprofloxacin 500 mg (o) 12-hourly for 3 days

• or

• norfloxacin 400 mg (o) 12-hourly for 5 days

Usually self-limiting, may need fluid and electrolytes and anti-motility agents.

If severe, nitazoxanide (shared care).

See CHAPTER 15.

• metronidazole 600–800 mg (o) tds for 6–10 days

• plus

• diloxanide furoate 500 mg (o) tds for 10 days

Pathogenicity is disputed: give therapy only if severe. Associated with poor hygiene (travel, pets, dam/tank water, oysters).

• metronidazole for 7 days

• Specialist advice should be sought.

Treatment for special enteric infections

See CHAPTER 15.

• azithromycin 1 g (o) daily for 7 days

• or

• (if not acquired in the Indian subcontinent or SE Asia)

• ciprofloxacin 500 mg (o) 12-hourly for 7–10 days (use IV if oral therapy not tolerated)

If ciprofloxacin is contraindicated (e.g. in children) or not tolerated, then use:

• ceftriaxone 3 g IV daily until culture and

• sensitivities available, then choose oral regimens

If severe: administer same drug and dosage IV for first 4–5 days.

Antibiotic therapy reduces the volume and duration of diarrhoea. Rehydration is the key.

• azithromycin 1 g (child 20 mg/kg up to 1 g) (o) as a single dose

• or

• ciprofloxacin 1 g (o) as a single dose

For pregnant women and children:

• amoxycillin (child: 10 mg/kg up to) 250 mg (o)

• 6-hourly for 4 days

Inflammatory bowel disease (IBD) should be considered when a young person presents with:

• bloody diarrhoea and mucus

• colonic pain and fever

• urgency to visit toilet and feeling of incomplete defecation

• constitutional symptoms including weight loss and malaise

• extra-abdominal manifestations such as arthralgia, low back pain (spondyloarthropathy), eye problems (iridocyclitis), liver disease and skin lesions (pyoderma gangrenosum, erythema nodosum)

Investigations include FBE, vitamin B12 and folate, LFTs (abnormal enzymes), HLA B₂₇, faecal calprotectin (if normal, no intestinal inflammation; if abnormal, needs colonoscopy) and lactoferrin.

Two important disorders are ulcerative colitis (UC) and Crohn disease, which have equal sex incidence and can occur at any age, but onset peaks between 20 and 40 years.

Ulcerative colitis

Clinical features

• Mainly a disease of Western societies

• Mainly in young adults (15–40 years)

• High-risk factors—family history, previous attacks, low-fibre diet

• Recurrent attacks of loose stools

• Blood, or blood and pus, or mucus in stools

• Abdominal pain slight or absent

• Fever, malaise and weight loss uncommon

• Begins in rectum (continues proximally)—affects only the colon: it usually does not spread beyond the ileocaecal valve

• An increased risk of carcinoma after 7–10 years

Main symptom

• Bloody diarrhoea

Diagnosis

• Faecal calprotectin: a sensitive test

• Proctosigmoidoscopy: a granular red proctitis with contact bleeding

• Barium enema: characteristic changes

Prognosis

• 5% mortality in an acute attack

• Recurrent attacks common

Crohn disease

Synonyms: regional enteritis, granulomatous colitis.

The cause is unknown but there is a genetic link.

Clinical features

• Recurrent diarrhoea in a young person (15–40 years)

• Blood and mucus in stools (less than UC)

• Colicky abdominal pain (small bowel colic)

• Right iliac fossa pain (confused with appendicitis)

• Constitutional symptoms (e.g. fever, weight loss, malaise, anorexia, nausea)

• Signs include perianal disorders (e.g. anal fissure, fistula, ischiorectal abscess), mouth ulcers

• Skip areas in bowel: ½ ileocolic, ¼ confined to small bowel, ¼ confined to colon, 4% in upper GIT

Main symptom

• Colicky abdominal pain

Diagnosis

• Sigmoidoscopy: ‘cobblestone’ appearance (patchy mucosal oedema)

• Colonoscopy: useful to differentiate from UC

• Biopsy with endoscopy

Prognosis

Less favourable than UC with both medical and surgical treatment.

Management principles of both

• Education and support, including support groups

• Treat under consultant supervision

• Treatment of acute attacks depends on severity of the attack and the extent of the disorder:

  • – mild attacks: manage out of hospital

  • – severe attacks: hospital, to attend to fluid and electrolyte balance

• Role of diet controversial: consider a high-fibre diet but maintain adequate nutrition

• Pharmaceutical agents (the following can be considered):

  • – 5-aminosalicylic acid derivatives (mainly UC): sulfasalazine (mainstay), olsalazine, mesalazine. Usually start with these agents

  • – corticosteroids (mainly for acute flares): oral, parenteral, topical (rectal foam, suppositories or enemas)

  • – for severe disease, immunomodifying drugs (e.g. azathioprine, cyclosporin, methotrexate) and biological agents (e.g. infliximab)

• Surgical treatment: reserve for complications; avoid surgery if possible

Alternating diarrhoea and constipation are well-known symptoms of incomplete bowel obstruction (cancer of colon and diverticular disease) and irritable bowel syndrome.

Irritable bowel syndrome (IBS)^3,8,10

Clinical features

• Typically in younger women (21–40 years)

• Any age or sex can be affected

• May follow attack of gastroenteritis/traveller’s diarrhoea

• Cramping abdominal pain (central or iliac fossa)—see FIGURE 44.4

• Pain usually relieved by passing flatus or by defecation

• Variable bowel habit (constipation more common)

• Diarrhoea usually worse in morning—several loose, explosive bowel actions with urgency

• The Bristol stool chart was devised to assist with the subclassification of stool types and bowel habits <www.continence.org.au/pages/bristol-stool-chart.html>

• Often precipitated by eating

• Faeces sometimes like small, hard pellets or ribbon-like

• Anorexia and nausea (sometimes)

• Bloating, abdominal distension, borborygmi

• Tiredness common

The Rome III diagnostic criteria for IBS are presented in TABLE 44.11.

IBS is a diagnosis of exclusion. A thorough physical examination, investigations (FBE, ESR and stool microscopy or culture) and colonoscopy are necessary. Insufflation of air at colonoscopy may reproduce the abdominal pain of IBS.

Possible related causes

Bowel infection, food irritation (e.g. spicy foods), lactose (milk) intolerance, excess-fibre wheat products, high fatty foods, carbonated drinks, laxative overuse, use of antibiotics and codeine-containing analgesics, psychological factors.

Management

The patient must be reassured and educated with advice that the problem will not cause malignancy or inflammatory bowel disease and will not shorten life expectancy. The basis of initial treatment is simple dietary modification (FODMAPs), exercise, fluids (2–3 L water daily) and non-fermentable fibre.

Self-help advice to the patient

Anyone with IBS should try to work on the things that make the symptoms worse. If you recognise stresses and strains in your life, try to develop a more relaxed lifestyle. You may have to be less of a perfectionist in your approach to life.

Focus on establishing a regular eating pattern. Try to avoid any foods that you can identify as causing the problem. You may have to cut out smoking and alcohol and avoid laxatives and codeine (in painkillers). A high-fibre (non-fermentable) and low-carbohydrate diet and 2–3 L of water a day may be the answer to your problem.

A low-FODMAP diet can produce good benefits.¹¹ FODMAP refers to fermentable oligosaccharides, disaccharides, monosaccharides and polyols, which are poorly absorbed. All of these carbohydrates need to be eliminated (under a dietitian’s guidance) then reintroduced one at a time.

See <www.med.monash.edu/cecs/gastro/fodmap>, available as an app—the Monash University Low-FODMAP Diet.

Diverticular disorder

Diverticular disorder is a problem of the colon (90% in descending colon) and is related to lack of fibre in the diet. It is usually symptomless.

Clinical features

• Typical in middle-aged or elderly—over 40 years

• Increases with age

• Present in one in three people over 60 years (Western world)

• Diverticulosis—symptomless

• Diverticulitis—infected diverticula and symptomatic (refer CHAPTER 34)

• Constipation or alternating constipation/diarrhoea

• Intermittent cramping lower abdominal pain in LIF

• Tenderness in LIF

• Rectal bleeding—may be profuse (± faeces)

• May present as acute abdomen or subacute obstruction

• Usually settles in 2–3 days

Complications (of diverticulitis)

• Abscess

• Perforation

• Peritonitis

• Obstruction (refer CHAPTER 34)

• Fistula—bladder, vagina

Investigations

• WBC and ESR—to determine inflammation

• Sigmoidoscopy

• Barium enema

Management

• It usually responds to a high-fibre diet.

• Avoidance of constipation.

Advice to the patient

The gradual introduction of fibre with plenty of fluids (especially water) will improve any symptoms you may have and reduce the risk of complications. Your diet should include:

1. cereals, such as bran, shredded wheat, muesli or porridge

2. wholemeal and multigrain breads

3. fresh or stewed fruits and vegetables

Bran can be added to your cereal or stewed fruit, starting with 1 tablespoon and gradually increasing to 3 tablespoons a day. Fibre can make you feel uncomfortable for the first few weeks, but the bowel soon settles with your improved diet.

Children with diarrhoea

• Infant under 3 months

• Moderate to severe dehydration

• Diagnosis of diarrhoea and vomiting in doubt (e.g. blood in vomitus or stool, bile-stained vomiting, high fever or toxaemia, abdominal signs suggestive of appendicitis or obstruction)

• Failure to improve or deterioration

• A pre-existing chronic illness

Adults with diarrhoea

• Patient with chronic or bloody diarrhoea

• Any problem requiring colonoscopic investigation

• Patients with anaemia

• Patients with weight loss, abdominal mass or suspicion of neoplasia

• Patients with anal fistulae

• Patients not responding to treatment for giardiasis

• Infection with E. histolytica

• Long-term asymptomatic carrier of typhoid or paratyphoid fever

• Patient with persistent undiagnosed nocturnal diarrhoea

• Patients with IBS with a significant change in symptoms

• Patients with inflammatory bowel diseases with severe exacerbations, possibly requiring immunosuppressive therapy and with complications

• Patients with ulcerative colitis of more than 7 years’ duration (screening by colonoscopy for carcinoma)

Hand-out sheets from Murtagh’s Patient Education 7th edition:

• Coeliac disease in adults

• Coeliac disease in children

• Diarrhoea—acute diarrhoea in adults

• Gastroenteritis in children