Diarrhea, a multifactorial disease

Acute diarrhea is defined as the abrupt onset of three or more loose stools per day with increased water content, volume, or frequency and which lasts no longer than 14 days.1,2 However, in healthy people the frequency of passing stool can range from several times a day to several times per week.3 Conversely, chronic or persistent diarrhea is defined as an episode that lasts longer than 14 days.


Acute diarrhea is a multifactorial disease, with a complex pathophysiology

Infectious causes include:

Viruses, bacterial and and occasionally parasites.2
Viral gastroenteritis is the most common cause of diarrhea and is generally self - limitating.2

Non-infectious causes include:

Adverse effects of medication, acute abdominal processes, gastroenterological disease and endocrine disease.2

The alteration of the intestinal microbiota, irrespective of cause, is a significant contributing factor to diarrhea. An unbalanced or disturbed microbiota is a predisposing factor to aberrant inflammatory responses, which can lead to the intestinal barrier becoming compromised promoting further inflammation, electrolyte leakage and impaired nutrient absorption.4

Antibiotic - associated diarrhea

One mechanism by which antibiotics cause diarrhea is by upsetting the balance of bacteria in the microbiota, with a resultant decrease in bacterial fermentation and an increase in undigested carbohydrates in the faeces.5 Treatment includes methods of re - establishing the balance to the microbiota, which can include postbiotics such as Lactéol®.6 Postbotics have a demonstrated efficacy in the treatment of antibotic - associated diarrhea,6,7 and because they have been inactivated, they can be safely co - administrated with antibiotics, without impact on its efficacy.8


There are a four mechanisms that contribute to diarrhea, these may be present alone or in combinations.3 All mechanisms govern water flow between the body and the gut lumen.

  • Increased luminal osmolarity resulting in water flow into the gut lumen from the body
  • Decreased fluid absorption from the gut, often following damage to the mucosa
  • Hyper - secretion of electrolytes into the gut lumen in response to agents such as microbial toxins: the increase in electrolyte concentration results in water flow into the gut from the body
  • An increase in intestinal motility and a decrease in intestinal transit time, this results in a decrease in the amount of water that is absorbed from the gut lumen


Laboratory work and stool culture are generally not required2

As diarrhea is generally self - limiting, a laboratory workup and stool culture are not required for most patients. Diagnostic investigation is usually reserved for those patients with severe dehydration, persistent fever, bloody stool, immunosuppression and where a nosocomial outbreak is suspected.2

In these serious cases, a 5 - step approach to defining the diarrhea may be helpful:9

Does the patient really have diarrhea? Beware of faecal incontinence and impaction

Rule out medications as a cause of diarrhea

Differentiate acute from chronic diarrhea

Categorise the diarrhea as inflammatory, fatty or watery

Consider spurious diarrhea

In general practice, patients presenting with diarrhea should be evaluated for signs of dehydration, namely: decreased urine output, thirst, dizziness and change in mental status.2 The primary goal of the physical examination is to assess the degree of dehydration.2

Vomiting is more suggestive of a viral illness or an ingested bacterial toxin; whereas, fever, tenesmus and bloody stool are suggestive of a bacterial infection.2

Management of diarrhea

The goals of diarrhea management are threefold:2


Prevent or reverse dehydration with oral rehydration therapy


Reduce the duration and the intensity of the diarrhea


Fight the causal micro - organism infection, if there is one

Oral rehydration therapy is the universally - recommend treatment 10 ‑ 12

First - line treatment is thus focussed on the prevention and immediate treatment of dehydration, preferably using oral rehydration salt solutions.2 Normal food intake should be resumed as soon as possible as this may reduce the duration of the diarrhea and it is important to minimise malnutrition in some settings.11 Some physicians recommend the BRAT diet (of Bananas, Rice, Applesauce, and Toast) and recommend avoiding dairy products; however, the evidence for these interventions is anecdotal.2

Treatment to reduce the stool frequency and improve consistency

A number of treatments are available that have been shown to reduce stool frequency, including zinc supplementation and ‘biotics’. ln addition to rehydration, studies suggest that taking ‘biotics’, which include probiotics and postbiotics, shortens the duration of diarrhea.2,13,14 An example of a postbiotic is heat - treated Lactobacillus LB and its culture medium, which shortens the duration of diarrhea and improves stool frequency.6, 15-17

Zinc supplements reduce duration and severity of the diarrhea

ln contexts where there is potential for zinc deficiency, zinc supplementation in addition to oral rehydration therapy is recommended for chidren.18 The WHO recommends a dose of 20 mg per day from 6 months of age, and 10 mg per day under 6 months.19

Postbiotics have a good safety profile and are effective for the treatment of diarrhea
Postbiotics are defined as non - viable bacterial products and/or metabolic products from micro - organisms that have biologic activity in the host.13 They have been shown to be effective and well tolerated in both the prevention and treatment of diarrhea.7 Lactéol® is defined as a postbiotic, and has an established safety and efficacy profile in both children and adults.20 As a result of this favourable profile, Lactéol® is included in the ESPGHAN recommendations for the treatment of diarrhea.21

International guidelines for the treatment of diarrhea:

ESPGHAN: European Society of Paediatric Gastroenterology Hepatology and Nutrition; WHO: World Health Organization.

  1. Diarrhea. Medscape, 2020. (Accessed September 2020, at https://emedicine.medscape.com/article/928598-overview.)
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  12. Guarino A, Ashkenazi S, Gendrel D, Lo Vecchio A, Shamir R, Szajewska H. European Society for Pediatric Gastroenterology, Hepatology, and Nutrition/European Society for Pediatric Infectious Diseases evidence-based guidelines for the management of acute gastroenteritis in children in Europe: update 2014. J Pediatr Gastroenterol Nutr 2014;59:132-52.
  13. Martín R, Langella P. Emerging health concepts in the probiotics field: streamlining the definitions. Front Microbiol 2019;10:1047.
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  16. Tarrerias AL, Costil V, Vicari F, et al. The effect of inactivated Lactobacillus LB fermented culture medium on symptom severity: observational investigation in 297 patients with diarrhea-predominant irritable bowel syndrome. Dig Dis 2011;29:588-91.
  17. Simakachorn N, Pichaipat V, Rithipornpaisarn P, Kongkaew C, Tongpradit P, Varavithya W. Clinical evaluation of the addition of lyophilized, heat-killed Lactobacillus acidophilus LB to oral rehydration therapy in the treatment of acute diarrhea in children. J Pediatr Gastroenterol Nutr 2000;30:68-72.
  18. Brandt KG, Castro Antunes MM, Silva GA. Acute diarrhea: evidence-based management. J Pediatr (Rio J) 2015;91:S36-43.
  19. The treatment of diarrhoea. A manual for physicians and other senior health workers. Geneva: World Health Organization; 2005.
  20. Liévin-Le Moal V. A gastrointestinal anti-infectious biotherapeutic agent: the heat-treated Lactobacillus LB. Therap Adv Gastroenterol 2016;9:57-75.
  21. Szajewska H, Guarino A Fau - Hojsak I, Hojsak I Fau - Indrio F, et al. Use of probiotics for management of acute gastroenteritis: a position paper by the ESPGHAN Working Group for Probiotics and Prebiotics.

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A diverse range of educational and relevant information concerning Lactéol® heat – treated micro – organisms, postbiotics, the microbiota and the consequences of dysbiosis are available here …

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