Shigellosis

Shigellosis is a highly contagious bacterial infection resulting in bloody diarrhoea. There are 4 serogroups of shigella: S. dysenteriae, S. sonnei, S. flexneri, S. boydii.

S. dysenteriae type 1 (Sd1) is the only strain that causes large scale outbreaks. It has the highest case fatality rate (up to 10%). 

Patients at risk of death are children under 5 years, malnourished patients, children after measles, adults over 50 years.

Clinical features

• Diarrhoea with bright red blood visible in stool a Citation a. This definition excludes: blood detected on microscope examination; stool containing digested blood (melaena); streaks of blood on the surface of normal stool (haemorrhoids, anal or rectal lesion, etc.). , with or without fever 
• Abdominal and rectal pain frequent
• Signs of serious illness: fever above 39 °C; severe dehydration; seizures, altered mental status
• Complications (more frequent with Sd1): febrile seizures (5 to 30% of children), rectal prolapse (3%), septicaemia, intestinal obstruction or perforation, moderate to severe haemolytic uraemic syndrome

Laboratory

Shigellosis in an epidemic context:

• Confirm the causal agent (stool culture) and perform antibiotic sensitivity tests.
• Perform monthly culture and sensitivity tests (antibiotic resistance can develop rapidly, sometimes during the course of an outbreak).

Treatment

• Patients with signs of serious illness or with life-threatening risk factors must be admitted as inpatients.

• Treat patients with neither signs of serious illness nor risk factors as outpatients.

• Antibiotherapy:

If resistance or contra-indication to ciprofloxacin or if no improvement within 48 hours of starting first-line treatment:

azithromycin PO for 5 days
Children: one dose of 12 mg/kg on D1 then 6 mg/kg once daily from D2 to D5
Adults: one dose of 500 mg on D1 then 250 mg once daily from D2 to D5
or
cefixime PO for 5 days
Children: 8 mg/kg once daily (max. 400 mg daily)
Adults: 400 mg once daily

If there is no improvement 48 hours after starting second-line treatment, treat for amoebiasis [1] Citation 1. Karen L. Kotloff et al. Seminar: Shigellosis. The Lancet, Volume 391, ISSUE 10122, P801-812, February 24, 2018. [2] Citation 2. Word Health Organization. Pocket book for hospital care in children: guidelines for the management of common childhood illnesses, 2013.
http://apps.who.int/iris/bitstream/handle/10665/81170/9789241548373_eng.pdf;jsessionid=CE5C46916607EF413AA9FCA89B84163F?sequence=1 [Accessed 20 September 2018] .

• For pain and/or fever:
  paracetamol PO (see Pain, Chapter 1). All opioid analgesics are contra-indicated as they slow peristalsis.

• Supportive therapy:
  • nutrition: nutritional supplement with frequent meals 
    + 2500 kcal daily during hospitalisation 
    + 1000 kcal daily as outpatients 
  • rehydration: administration of ORS according to WHO protocols (see Dehydration, Chapter 1).
  • zinc supplement in children under 5 years (see Acute diarrhoea, Chapitre 3).

• Never give loperamide or any other antidiarrhoeal.

• Management of complications: rectal prolapse reduction, septicaemia (see Septic shock, Chapter 1), etc.

Shigellosis in an epidemic context 

• Isolation of hospitalised patients; school exclusion of children treated as outpatients.
• Hygiene (handwashing, hygienic preparation and storage of food, home hygiene, etc.).
• Management if signs worsen or bloody diarrhoea in entourage (seek medical attention).