Bacillary Dysentery
💡 About
- Shigellosis (bacillary dysentery) is a highly contagious acute intestinal infection transmitted via the faeco–oral route through contaminated food, water, or person-to-person contact.
- As few as 10–100 organisms can cause disease - outbreaks are common in nurseries, schools, and refugee camps.
🦠 Aetiology
- Shigella dysenteriae → most severe, produces Shiga toxin.
- Shigella flexneri, boydii, sonnei → cause milder disease.
- Incubation: 1–4 days.
- Bacteria invade colonic mucosa → ulceration, inflammation, bleeding.
- Shiga toxin → systemic toxicity, risk of HUS.
🩺 Clinical Features
- 💩 Diarrhoea → starts watery, becomes bloody and mucoid.
- 💥 Severe abdominal cramps & tenesmus.
- 🤢 Fever, anorexia, malaise.
- 💧 Signs of dehydration (tachycardia, sunken eyes, dry mucosa).
- ⚡ Children may present with febrile seizures.
🔍 Differentials
- Amoebic dysentery (Entamoeba histolytica).
- Salmonella or Campylobacter gastroenteritis.
- Clostridioides difficile colitis.
- Inflammatory bowel disease (UC/Crohn’s).
🧪 Investigations
- 🧪 Bloods: FBC (↑ WCC), U&E (AKI risk), LFTs.
- 💩 Stool microscopy & culture: confirms Shigella species.
- 🔬 Stool for ova/cysts → excludes amoebiasis.
- 🧬 Consider C. diff toxin in hospital-acquired cases.
⚡ Complications
- 💧 Severe dehydration & electrolyte imbalance.
- 🧬 Haemolytic Uraemic Syndrome (HUS) (esp. S. dysenteriae type 1).
- 🦵 Reactive arthritis (Reiter’s syndrome).
- ⚡ Seizures in children (often febrile).
💊 Management
- 💧 Supportive: Oral rehydration salts (ORS) or IV fluids if severe.
- 💊 Antibiotics: For severe/at-risk cases (children, elderly, immunocompromised) – Ciprofloxacin, azithromycin, or ceftriaxone (guided by BNF/local resistance).
- 🚫 Avoid antimotility agents (e.g., loperamide) → risk of toxin retention.
- 🧼 Infection control: strict hand hygiene, isolation, safe food handling.
🧾 Clinical Case Vignette
A 7-year-old boy is brought to A&E with a 2-day history of bloody diarrhoea, fever (39°C), and abdominal cramps.
His parents report several classmates are also unwell. On exam: tachycardia, dehydration, and tenderness in the left iliac fossa.
Stool culture confirms Shigella flexneri.
👉 Diagnosis: Bacillary dysentery (Shigellosis).
👉 Management: IV fluids for dehydration + oral ciprofloxacin; notified public health team.
📚 References
🧾 Clinical Case Example – Bacillary Dysentery (Shigella)
Case – Child with Bloody Diarrhoea 🧒💩
A 7-year-old boy is brought to A&E with a 2-day history of high fever, abdominal cramps, and frequent small-volume stools mixed with blood and mucus.
He attends a primary school where several classmates are also unwell. On exam: febrile (39°C), tachycardic, dehydrated, with tender left iliac fossa but no peritonitis.
Stool culture grows Shigella flexneri.
👉 Diagnosis: Bacillary dysentery.
👉 Management: Oral rehydration (or IV if severe), notify public health, and antibiotics (ciprofloxacin or azithromycin depending on resistance).
