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Gastrointestinal & Hepatic System

Bacillary Dysentery (Shigellosis)

An acute bacterial infection of the distal small intestine and colon caused by Shigella species. Characterized by diarrhoea, often with blood and mucus, fever, and abdominal cramps. Highly infectious via faecal-oral route.

Also known as: Shigellosis, Shigella Dysentery

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Referral and warning signs

When to refer

Refer to hospital (HC4/H) for: Severe dehydration requiring IV fluids. Signs of complications (seizures, toxic megacolon, suspected HUS). Infants < 6 months. Severely malnourished children. Failure to respond to appropriate oral antibiotics.

Red flags

  • Signs of severe dehydration or shock
  • Altered mental status / Seizures
  • Signs of toxic megacolon (abdominal distension, worsening pain, decreased bowel sounds)
  • Oliguria / Anuria (suggests HUS or severe dehydration)
  • Persistent high fever despite antibiotics

Signs and symptoms

  • Abrupt onset.
  • Diarrhoea (initially watery, progresses to frequent small-volume stools with blood and mucus).
  • Fever (often high).
  • Abdominal cramps (colicky pain).
  • Tenesmus (painful straining to defecate).
  • Nausea, vomiting.
  • Malaise, anorexia.
  • May present with watery diarrhoea initially.
  • Can cause seizures in young children (febrile or toxin-related).

Risk factors

  • Poor sanitation and hygiene.
  • Contaminated food or water.
  • Crowded conditions (daycare centres, institutions, refugee camps).
  • Young children (<5 years) - highest incidence.
  • Men who have sex with men.
  • Travel to endemic areas.

Diagnosis

Clinical assessment

Suspect in patients with acute onset fever, abdominal cramps, and bloody/mucoid diarrhoea, especially in outbreaks. Differentiate from amoebic dysentery (more gradual onset, less fever), EHEC/EIEC E. coli, Campylobacter, Salmonella enterocolitis, C. difficile colitis.

Investigations

  • Stool Examination:
  • - Microscopy: Shows numerous polymorphonuclear leukocytes (pus cells) and red blood cells.
  • - Stool Culture & Sensitivity: Confirms diagnosis and guides antibiotic choice (crucial due to increasing resistance).
  • Blood tests (if severe): CBC (leukocytosis, sometimes leukemoid reaction), U&Es (dehydration, electrolytes).

Diagnostic criteria

Clinical presentation consistent with dysentery, ideally confirmed by stool culture identifying Shigella species.

Management

Non-pharmacological management

  • Rehydration: Crucial. ORS for mild/moderate dehydration. IV fluids (Ringer's Lactate or Normal Saline) for severe dehydration or persistent vomiting (Plan B/C).
  • Nutritional Support: Continue feeding/breastfeeding.
  • Infection Control: Strict handwashing, proper disposal of faeces, contact precautions.

Pharmacological treatment

  • Antibiotics: Recommended to shorten duration, reduce severity, decrease transmission, especially in moderate/severe cases, outbreaks, or high-risk individuals.
  • - Preferred Agent (UCG 2023 for Cholera - likely applicable based on resistance patterns): Ciprofloxacin 1g PO single dose OR 500mg PO BID for 3-5 days (Adult); 15mg/kg PO BID for 3 days (Child). Check local resistance patterns.
  • - Alternative: Azithromycin 1g PO single dose (Adult); 10-12mg/kg PO daily for 3-5 days (Child).
  • - Ceftriaxone IV/IM may be used for severe cases or if unable to take oral medication.
  • - Resistance to Ampicillin and TMP-SMX is widespread; generally avoid unless known susceptibility.
  • Antimotility Agents (e.g., Loperamide): CONTRAINDICATED - can prolong illness and increase risk of complications (toxic megacolon).
  • Zinc Supplementation: Recommended for children <5 years (see Diarrhoea section GI005).

Monitoring

  • Monitor hydration status.
  • Monitor stool frequency and character.
  • Monitor temperature.
  • Assess clinical response to antibiotics.

Complications

  • Severe dehydration, electrolyte imbalance, shock.
  • Seizures (especially in children).
  • Toxic megacolon.
  • Intestinal perforation (rare).
  • Haemolytic Uremic Syndrome (HUS) - associated with Shiga toxin-producing strains (esp. S. dysenteriae type 1).
  • Reactive arthritis (Reiter's syndrome).
  • Persistent diarrhoea / Malnutrition.
  • Rectal prolapse (due to straining).

Prevention

  • Handwashing with soap.
  • Safe water supply and sanitation.
  • Proper food handling.
  • Breastfeeding.
  • Prompt treatment of cases and contacts during outbreaks.

Patient education

  • Importance of rehydration with ORS.
  • Need to complete antibiotic course if prescribed.
  • Hygiene measures (handwashing, sanitation) to prevent spread.
  • Danger signs requiring immediate return to facility.
  • Continue feeding/breastfeeding.
  • Avoid antimotility drugs.

Uganda-specific notes

Shigellosis outbreaks occur. Stool culture often unavailable; treatment is empirical based on clinical suspicion and likely resistance patterns. Ciprofloxacin is often first-line per guidelines, but resistance is a concern. Importance of differentiating from amoebic dysentery.

References

  • Uganda Clinical Guidelines (UCG) 2023

    Chapter 6, Section 6.2.2

  • Uganda Clinical Guidelines (UCG) 2023

    Chapter 6, Section 6.2.3 (Cholera section for antibiotic guidance - Ciprofloxacin used for dysentery)

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