diagnosis and investigations in child with gastroenteritis

Last reviewed 01/2018

Mild dehydration which is being treated with oral fluids requires no further investigation.

Diagnosis and investigations:

• a stool sample is not a mandatory investigation in case of diarrhoea and vomiting in children
  • stool microbiological investigations should be performed if:
• septicaemia is suspected or
• there is blood and/or mucus in the stool or
• the child is immunocompromised
• in other circumstances when stool microbiological investigations should be considered include:
• the child has recently been abroad or
• the diarrhoea has not improved by day 7 or
• there is uncertainty about the diagnosis of gastroenteritis
• blood cultures
  • if giving antibiotic therapy then perform a blood culture
• blood biochemical testing is not routinely indicated
  • measurement of plasma sodium, potassium, urea, creatinine and glucose concentrations is indicated if:
    • intravenous fluid therapy is required or
    • there are symptoms and/or signs that suggest hypernatraemia
• venous blood acid-base status and chloride concentration is indicated if shock is suspected or confirmed

If the diarrhoea is bloody then a full blood count, blood cultures and urea and electrolytes should be performed. If the haemoglobin is low then haemolytic uraemic syndrome should be considered and a film should be asked for to see if there are fragmented red blood cells.

Reference:

• 1. NICE (April 2009). Diarrhoea and vomiting in children