Traveller's diarrhoea

Overview 
Theory 
Diagnosis 
Management 
Follow up 
Resources 

The usual management approach for traveller's diarrhoea (TD) is self-diagnosis while still travelling, followed by hydration, medicine for symptom relief, and possibly antibiotic treatment. Antibiotic therapy is generally reserved for moderate to severe infections. Vomiting alone suggests food poisoning or viral gastroenteritis and does not usually warrant antibiotic treatment. Self-treatment is designed to minimise discomfort and inconvenience.

Although healthy young people recover promptly, even without treatment, older people or those with underlying medical conditions may become severely ill for over 1 week and require intravenous hydration. Children often become more ill and take longer to recover.

All patients should seek care if symptoms worsen after starting treatment, or if symptoms do not begin to resolve 24-36 hours after starting appropriate antibiotic therapy.

Prophylaxis

Preventive actions include careful selection of safe food and beverages.[2][22] Unsafe items include ice, tap water, salads, previously peeled fruits, and raw foods. Unpackaged condiments and sauces, such as guacamole, often pose a significant risk. Food from street vendors and buffets with poor food turnover also pose a notable risk of food poisoning. Safe items include thoroughly cooked food served while still hot, boiled or bottled (properly sealed) water, commercially packaged foods, fresh breads, and fruits peeled by the traveller.

Prophylactic antibiotics are not recommended for most travellers.[1][2] Occasional exceptions include short-term critical itineraries such as diplomatic missions, professional sports, and critical business/life event engagements; and chronically ill or immunocompromised patients on trips of less than 3 weeks' duration. Rifaximin is considered the treatment of choice for prophylaxis; it is effective at preventing TD with no increase in adverse effects (compared with placebo).[1][23][24] Rifamycin can also be considered.[2] Fluoroquinolones are not recommended for the prophylaxis of TD.[1] Antibiotic prophylaxis is not usually recommended in children.

There is strong evidence to suggest that bismuth subsalicylate can reduce the incidence of TD by >60%; however, due to the number of tablets required and the inconvenient dosing, it is not commonly used as prophylaxis for TD.[26][27] Studies have not established the safety of this drug when used for >4 weeks.[1]

Rehydration

Fluid replacement is important in all patients. It is critical for older patients who are at risk of dehydration-related complications, pregnant women, infants, and younger children.[2][29] [ ] Bowel rest should be avoided.

The treatment for infants and young children should prioritise rehydration over antibiotics. Oral rehydration solutions (ORS), available as oral rehydration salt solution or rice-based solutions from pharmacies in many high-risk countries, are very effective for the management of dehydration associated with diarrhoea in infants.[2] Spoon-feeding oral rehydration salts is recommended if a child is vomiting. Additionally, infants and children who are breastfed should continue to breastfeed despite experiencing diarrhoea.

Adults with mild diarrhoea who find ORS unpalatable may rehydrate with any preferred liquid, although sugar-sweetened beverages can cause osmotic diarrhoea if consumed in large amounts.[2][28]

Antibiotic therapy

Antibiotics may be considered in patients with moderate infection (i.e., diarrhoea that is distressing or interferes with planned activities), and are always recommended in severe infection (i.e., diarrhoea that is incapacitating or completely prevents planned activities; dysentery and febrile diarrhoea are considered severe).[1] Antibiotics are not recommended in patients with mild infection (i.e., diarrhoea that is tolerable, is not distressing, and does not interfere with planned activities) unless their symptoms worsen.[2]

Antibiotic treatment is associated with a shorter duration of diarrhoea.[28] Antibiotic treatment with adjunctive loperamide consistently demonstrates the most rapid time to clinical cure (median 12-14 hours) compared with antibiotics alone (24-30 hours); however, antibiotic therapy (with or without adjunctive therapy) can be associated with a higher incidence of adverse effects, although these are often minor and self-limited.[32]

Self-treatment

The patient’s decision to treat themselves is based on their tolerance of the discomfort, concerns about the unintended consequences of antibiotic use in relation to adverse effects, and the real (but uncertain) impact of increased rates of intestinal colonisation with multidrug-resistant organisms associated with antibiotic use in the travel setting.

Self-treatment of mild to moderate TD is becoming more controversial because of public health concerns. One study found that 21% of travellers taking antibiotics for TD became colonised by extended-spectrum beta-lactamase-producing Enterobacteriaceae, and, because of this, concluded that antibiotics for mild to moderate TD should be avoided. The risks (public health concerns) should be weighed against the benefits (e.g., faster recovery time, avoidance of local health care system exposure for the individual) in each individual case.[33][34]

Choice of antibiotic

This depends on many factors including cost, individual preferences, geographical travel location, and additional coverage needed (systemic antibiotics that cover both watery TD and dysentery also treat many incidental infections, such as respiratory or urinary tract infections). Options for the treatment of TD include azithromycin, a fluoroquinolone, rifaximin, or rifamycin.[1][2]

Azithromycin is usually considered first-line because it covers dysenteric aetiologies, and is well tolerated with minimal adverse effects. Gastrointestinal complaints (e.g., nausea/vomiting) in the setting of gastrointestinal infections are occasionally seen with azithromycin, and are more common than in the treatment of non-gastrointestinal infections. Azithromycin is the preferred option for severe diarrhoea (including dysentery or febrile diarrhoea).

Fluoroquinolones are considered a second-line option. Systemic fluoroquinolone antibiotics may cause serious, disabling, and potentially long-lasting or irreversible adverse events. These include, but are not limited to: tendinopathy/tendon rupture; peripheral neuropathy; arthropathy/arthralgia; aortic aneurysm and dissection; heart valve regurgitation; dysglycaemia; and central nervous system effects including seizures, depression, psychosis, and suicidal thoughts and behaviour.[35]

Prescribing restrictions apply to the use of fluoroquinolones, and these restrictions may vary between countries. In general, fluoroquinolones should be restricted for use in serious, life-threatening bacterial infections only. Some regulatory agencies may also recommend that they must only be used in situations where other antibiotics that are commonly recommended for the infection are inappropriate (e.g., resistance, contraindications, treatment failure, unavailability).
Consult your local guidelines and drug formulary for more information on suitability, contraindications, and precautions.

Increased resistance against fluoroquinolones in Southeast Asia and other regions should be considered.

Rifaximin is another second-line option. Because it is largely unabsorbed by the gastrointestinal tract, it may be the most suitable option for patients taking other medicines as it is less likely to undergo drug-to-drug interactions. However, it may be less effective in Asia, where invasive pathogens (e.g., Campylobacter, Salmonella, Shigella) are more likely.[1]

Rifamycin is an alternative to rifaximin.[2] It can be used in adults with TD caused by non-invasive strains of Escherichia coli, not complicated by fever or blood in the stool.[2] Both rifaximin and rifamycin can be used for treating patients with severe, non-dysenteric diarrhoea.[2]

Pregnancy and children

Azithromycin is the treatment of choice in pregnant women with moderate to severe infection.

Trimethoprim/sulfamethoxazole and doxycycline are no longer recommended outside of special situations due to widespread resistance problems.

Antibiotics are recommended in children with moderate to severe infection, especially when there is bloody or severe watery diarrhoea, or evidence of systemic infection. Azithromycin is the treatment of choice in children. Rifaximin or a fluoroquinolone may be used as an alternative in children; however, rifaximin is not approved for children aged <12 years, and fluoroquinolones should be used with caution in children as they may increase the risk of joint and tendon disorders (see caution above).[2][36] Rifamycin is approved for use only in adults.[2]

Duration of therapy

Many experts recommend taking antibiotics only until the patient feels better, usually 1-3 days (with the exception of rifaximin and rifamycin, which should be taken for the full 3-day course). If symptoms have not resolved after 24 hours, the regimen should be taken for up to 3 days.[1]

Adjunctive therapies

Include loperamide, an anti-motility agent, and bismuth subsalicylate, an anti-diarrhoeal agent recommended for the treatment of mild infections.

Loperamide

An anti-motility agent commonly used for the treatment of diarrhoea, loperamide controls cramping and diarrhoea.[37][38] Loperamide is recommended as monotherapy in patients with mild to moderate infection, or can be used as an adjunct to antibiotic therapy in patients with moderate to severe infection. Patients should be advised that it can take 1-2 hours for loperamide to take effect, and additional dosing should be spaced accordingly to avoid rebound constipation.

Loperamide should not be used in patients with visible blood in the stool or high fever (characteristic of dysentery). Loperamide slows gastrointestinal transit time and, theoretically, may delay the expulsion of invasive bacteria.

Although there have been few published cases of significant adverse effects related to the use of loperamide in TD, the continued use of loperamide in patients with worsening symptoms, or the development of dysentery, is not recommended.[37] Loperamide is not recommended in pregnant women, and generally not recommended in children aged <6 years.

Bismuth subsalicylate

An oral anti-diarrhoeal agent recommended for the treatment of mild infections. Adverse effects include salicylate toxicity (e.g., tinnitus) and blackening of the tongue or stools.[27][39] Bismuth subsalicylate is not recommended in pregnant women or children aged <3 years.[2] It is not generally recommended in children aged <12 years due to the risk of Reye's syndrome; however, some physicians still use it with caution.[2]

Failure to respond to antibiotic therapy

Failure to respond to antibiotic therapy suggests a parasitic or post-infectious aetiology. Viral diarrhoea usually resolves quickly. Order stool antigen testing, polymerase chain reaction test, or ova and parasite examination to test for protozoal pathogens in patients with persistent diarrhoea (>14 days).[7]

Treatment for the identified pathogen should be started once results are back. See Giardiasis (Management) and Amoebiasis (Management).

If Clostridioides difficile-associated disease is suspected, the patient should be managed according to current guidelines. See Clostridiodes difficile-associated disease (Management).

Consult a specialist for the treatment of pregnant women and children with persistent diarrhoea.

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