Describe the bloody Diarrhoea of Acute Dysentery.

Definition

• Dysentery is diarrhoea with visible blood (and often mucus) in the stool, reflecting invasion and inflammation of the colonic mucosa.
• Unlike acute watery diarrhoea (a fluid-loss problem), dysentery is primarily an invasive mucosal infection and carries a risk of serious complications.

Etiology

• Shigella — the commonest and most important cause of acute bacillary dysentery (S. Flexneri, S. Dysenteriae).
• Other bacteria — enteroinvasive/enterohaemorrhagic E. Coli (EHEC), Campylobacter, Salmonella, Yersinia.
• Entamoeba histolytica — amoebic dysentery (more insidious).
• Non-infective — intussusception, Meckel's diverticulum, IBD (consider if atypical).

Bacillary VS Amoebic Dysentery

Clinical Features

• Frequent, small-volume bloody-mucoid stools with tenesmus and cramping abdominal pain.
• Fever (often high), anorexia, and rapid weight loss.
• Shigella can cause convulsions, altered sensorium and rectal prolapse, especially in young children.

Investigations

• Stool microscopy — pus cells, RBCs, and amoebic trophozoites (with ingested RBCs) if amoebiasis.
• Stool culture & sensitivity (Shigella); CBC (leukocytosis; anaemia).
• Electrolytes, renal function; monitor for complications (e.g. HUS with EHEC).

Management

• Assess & treat dehydration (Plans A/B/C) and continue feeding — nutrition is vital as dysentery rapidly worsens nutritional status.
• Antibiotics are indicated (unlike watery diarrhoea): first-line for shigellosis is ciprofloxacin (or azithromycin / ceftriaxone as per sensitivity) for ~3–5 days.
• Amoebic dysentery: metronidazole (30–50 mg/kg/day × 7–10 days) followed by a luminal amoebicide (diloxanide furoate).
• Zinc for 14 days; vitamin A; treat associated malnutrition.
• Avoid anti-motility drugs (they worsen invasive disease).

Complications

• Shigella: convulsions, toxic megacolon, intestinal perforation, rectal prolapse, reactive arthritis, and haemolytic uraemic syndrome (HUS) (esp. S. Dysenteriae type 1 & EHEC).
• Amoebic: liver abscess, amoeboma, perforation.
• Rapid dehydration, electrolyte imbalance and severe malnutrition.

Prevention

• Safe drinking water, sanitation and hand-washing (faeco-oral spread).
• Exclusive breastfeeding; hygienic food handling; prompt recognition & treatment.
• Improved nutrition and vitamin A/zinc to reduce severity.

Epidemiology & Pathogenesis

• Spread is faeco-oral via contaminated food/water and person-to-person; a very low infective dose makes Shigella highly contagious.
• Organisms invade the colonic epithelium, multiply, and produce inflammation, ulceration and micro-abscesses → blood, mucus and pus in the stool.
• S. Dysenteriae type 1 produces Shiga toxin, which can damage vascular endothelium and precipitate haemolytic uraemic syndrome.

Haemolytic Uraemic Syndrome (hus) — Key Complication

• A triad of microangiopathic haemolytic anaemia, thrombocytopenia and acute kidney injury.
• Follows Shiga-toxin-producing infection (S. Dysenteriae type 1 / EHEC O157:H7); presents with pallor, oliguria and bleeding.
• Avoid antibiotics and anti-motility drugs in suspected EHEC, as they may increase the risk of HUS; management is largely supportive (± dialysis).

Prognosis

With prompt rehydration, appropriate antibiotics and nutritional support, most children recover well; delay, malnutrition, very young age and complications (HUS, perforation, toxic megacolon) worsen the outcome.

Assessment at Presentation

• Confirm blood in the stool (visible or on microscopy) and assess the degree of dehydration (Plans A/B/C).
• Assess nutritional status — dysentery causes rapid protein loss and precipitates malnutrition.
• Look for danger signs — convulsions, abdominal distension (toxic megacolon), rectal prolapse, or signs of HUS (pallor, oliguria).

Dietary & Supportive Care

• Continue breastfeeding and give frequent, energy-dense feeds throughout the illness.
• Give an extra meal daily for 2 weeks after recovery to make up the nutritional loss.
• Ensure zinc (14 days) and vitamin A; treat anaemia and any associated infection.

Antibiotic Selection

Avoid antimotility drugs — risk of toxic megacolon.