Persistent Diarrhoea in Children
Lesson Objectives
By the end of this lesson, learners should be able to:
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Define persistent diarrhoea (PD) and understand its pathophysiology.
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Identify the clinical signs and symptoms of PD and associated complications.
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Classify the causes of PD according to pathophysiologic mechanisms.
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Interpret relevant laboratory and imaging investigations.
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Implement fluid, nutritional, and micronutrient management.
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Recognize indications for antimicrobial therapy.
Description
Persistent diarrhoea is defined as the passage of three or more watery stools within 24 hours that continues for more than 14 days. Major contributors include dehydration, malnutrition, and infections. Causes can be divided into four principal mechanisms: osmotic, secretory, dysmotility-associated, and inflammatory.
Signs and Symptoms
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Liquid stools often passed after meals, sometimes explosive
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Occasionally stool may contain visible blood
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Weight loss and malnutrition
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Signs of dehydration (see WHO table in acute diarrhoea lesson)
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Extra-intestinal infections: pneumonia, urinary tract infection
Causes of Persistent Diarrhoea
| Cause | Major Signs & Symptoms (in addition to PD) | Laboratory & Imaging Findings |
|---|---|---|
| Infectious (E. coli, Cryptosporidium, Giardia, Salmonella, E. histolytica) | Possible blood/mucus in stool, fever, abdominal pain | Positive stool culture, ova and parasite examination |
| Lactose malabsorption | Abdominal discomfort, bloating, flatulence | Elevated breath hydrogen concentration after lactose ingestion |
| Immunodeficiency | Recurrent infections, young age (infancy) | Low IgG, IgA; high IgM, lymphopenia, low vaccine antibody titers |
| Food allergy (cow or soy milk) | Hypoalbuminemia, anemia | Serum IgE may be elevated, electrolyte abnormalities |
| Hirschsprung disease | Delayed passage of meconium, distended abdomen, explosive stool | Abnormal barium enema, absent ganglion cells on rectal biopsy |
| Toddlers’ diarrhoea | Thriving toddler, often after sweetened juices | Normal lab and imaging results |
| Irritable bowel syndrome | Alternating constipation and diarrhoea, abdominal pain relieved by defecation | Usually diagnosed in adolescence, normal labs and imaging |
| Celiac disease | Failure to thrive, abdominal distension, vomiting | 9–24 months of age; elevated anti-TTG IgA, anti-endomysial IgA antibodies |
| Inflammatory bowel disease | Bloody stool, urgency, abdominal pain, fatigue, weight loss, arthritis | Elevated ESR, fecal calprotectin, thrombocytosis, iron-deficiency anemia, hypoalbuminemia |
Management
Fluid Therapy
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Provide appropriate fluids to prevent and treat dehydration (refer to WHO dehydration classification).
Nutritional Support
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Nutritious diet to promote weight gain. Avoid foods that worsen diarrhoea.
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Severe Acute Malnutrition (SAM) should be treated per SAM protocol.
Micronutrients
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Vitamins and minerals, including zinc supplementation for 10–14 days.
Antimicrobials
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Treat infections only when diagnosed (culture or evidence of infection).
Key Summary
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Persistent diarrhoea lasts >14 days and is often complicated by dehydration, malnutrition, and infection.
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Multiple pathophysiologic mechanisms exist: osmotic, secretory, dysmotility, inflammatory.
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Diagnosis relies on history, clinical exam, and targeted lab/imaging tests.
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Fluid management is critical, along with age-appropriate nutrition and micronutrient support.
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Antibiotics are not routinely indicated, only for proven infections.