Makindo Medical Notes

💡 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

• NHS – Shigella
• WHO – Shigella Fact Sheet
• BNF – Antibiotic guidance