Gastroenterology & Hepatology
Question 118 of 180
A 3 year old boy is brought to the Emergency Department by his father. He describes 4 days of vomiting and 3 days of diarrhoea. He has no significant past medical history and is up to date with his immunisations. On examination you note jittery movements and increased muscle tone. What investigation would be most useful in this patient?
Answer:
Routine blood biochemistry should not be performed in children with gastroenteritis. Measure laboratory U&Es and blood glucose if intravenous fluid is required or if hypernatraemic dehydration is suspected. Measure venous blood acid–base status and chloride concentration if shock is suspected or confirmed. Take blood cultures if starting antibiotics. Hypernatraemic dehydration (Na+ > 150 mmol/L) should be suspected if:- Jittery movements
- Increased muscle tone
- Hyperreflexia
- Convulsions
- Drowsiness or coma
Paediatric Gastroenteritis
Gastroenterology & Hepatology
Last Updated: 6th October 2022
Gastroenteritis should be suspected if there is a sudden change in stool consistency to loose or watery stools, and/or a sudden onset of vomiting. If you suspect gastroenteritis, ask about recent contact with someone with acute diarrhoea and/or vomiting and exposure to a known source of enteric infection (possibly contaminated water or food) and recent travel abroad.
Differential diagnosis
- Non-enteric infection
- Meningitis, septicaemia, urinary tract infection, pneumonia
- Non-infective gastrointestinal conditions
- Inflammatory bowel disease, coeliac disease, malabsorption, constipation with overflow diarrhoea
- Acute surgical abdominal conditions
- Appendicitis, volvulus, intussusception, pyloric stenosis
- Antibiotic associated diarrhoea (including C. diff)
Assessment of dehydration
The following are at increased risk of dehydration:
- Children younger than 1 year, particularly those younger than 6 months
- Infants who were of low birth weight
- Children who have passed more than five diarrhoeal stools in the previous 24 hours
- Children who have vomited more than twice in the previous 24 hours
- Children who have not been offered or have not been able to tolerate supplementary fluids before presentation
- Infants who have stopped breastfeeding during the illness
- Children with signs of malnutrition
| No clinically detectable dehydration | Clinical dehydration | Shock |
|---|---|---|
| Appears well | Appears to be unwell or deteriorating | / |
| Alert and responsive | Altered responsiveness (e.g. irritable, lethargic) | Decreased level of consciousness |
| Normal urine output | Decreased urine output | / |
| Skin colour unchanged | Skin colour unchanged | Pale or mottled skin |
| Warm extremities | Warm extremities | Cold extremities |
| Eyes not sunken | Sunken eyes | / |
| Moist mucous membranes | Dry mucous membranes | / |
| Normal heart rate | Tachycardia | Tachycardia |
| Normal breathing pattern | Tachypnoea | Tachypnoea |
| Normal peripheral pulses | Normal peripheral pulses | Weak peripheral pulses |
| Normal capillary refill time | Normal capillary refill time | Prolonged capillary refill time |
| Normal skin turgor | Reduced skin turgor | / |
| Normal blood pressure | Normal blood pressure | Hypotension |
* Red flag symptoms and signs indicating children at increased risk of progression to shock
Hypernatraemic dehydration (Na+ > 150 mmol/L) should be suspected if:
- Jittery movements
- Increased muscle tone
- Hyperreflexia
- Convulsions
- Drowsiness or coma
Investigations
Stool microbiology, culture and sensitivity should be performed if:
- Septicaemia is suspected
- There is blood and/or mucus in the stool
- The child is immunocompromised
Stool culture should also be considered if:
- The child has recently been abroad
- The diarrhoea has not improved by day 7
- There is uncertainty regarding the diagnosis of gastroenteritis
Other investigations:
- Routine blood biochemistry should not be performed in children with gastroenteritis.
- Measure laboratory U&Es and blood glucose if intravenous fluid is required or if hypernatraemic dehydration is suspected.
- Measure venous blood acid–base status and chloride concentration if shock is suspected or confirmed.
- Take blood cultures if starting antibiotics.
- In children with Shiga toxin-producing Escherichia coli (STEC) infection, seek specialist advice on monitoring for haemolytic uraemic syndrome.
Antibiotic therapy
- Do not routinely give antibiotics to children with gastroenteritis.
- Give antibiotic treatment to all children:
- with suspected or confirmed septicaemia
- with extra-intestinal spread of bacterial infection
- younger than 6 months with salmonella gastroenteritis
- who are malnourished or immunocompromised with salmonella gastroenteritis
- with Clostridium difficile-associated pseudomembranous enterocolitis, giardiasis, dysenteric shigellosis, dysenteric amoebiasis or cholera.
- For children who have recently been abroad, seek specialist advice about antibiotic therapy.
Management of children with non clinical dehydration
Most children with gastroenteritis can be safely managed at home with advice and support from a healthcare professional if necessary.
- Discharge home, reassure parents and carers and provide advice on:
- How to prevent dehydration
- Continue breast feeds and other milk feeds
- Encourage fluid intake, discourage fruit juices and carbonated drinks
- Offer oral rehydration solution as supplemental fluid if at increased risk of dehydration
- When/how to seek help if symptoms of dehydration develop (e.g. appearing to get more unwell, changing responsiveness, decreased urine output, pale or mottled skin, cold extremities)
- How to prevent spread of infection
- Good hygiene practices
- Children should not attend any school or other childcare facility while they have diarrhoea or vomiting caused by gastroenteritis
- Children should not go back to their school or other childcare facility until at least 48 hours after the last episode of diarrhoea or vomiting
- Children should not swim in swimming pools for 2 weeks after the last episode of diarrhoea
- Normal duration of symptoms
- Vomiting: usually lasts 1 - 2 days and in most children stops with 3 days
- Diarrhoea: usually lasts 5 - 7 days and in most children stops within 2 weeks
- How to prevent dehydration
Management of children with clinical dehydration
- Initial management is oral rehydration therapy (continue breastfeeding if applicable):
- Use low osmolarity oral rehydration solution (ORS)
- Give 50 ml/kg for deficit replacement over 4 hours plus maintenance fluids
- Give the ORS solution frequently and in small amounts
- Consider supplementation with their usual fluids if they refuse to take sufficient quantities of ORS solution and do not have red flag symptoms or signs
- Consider giving the ORS solution via a nasogastric tube if they are unable to drink it or if they vomit persistently
- Monitor the response to oral rehydration therapy by regular clinical assessment
- Intravenous fluids are recommended in children with clinical dehydration if:
- Shock is suspected or confirmed
- A child with red flag symptoms or signs (see table) shows clinical evidence of deterioration despite oral rehydration therapy
- A child persistently vomits the ORS solution, given orally or via a nasogastric tube
- If intravenous fluid therapy is required for shock:
- Treat suspected or confirmed shock with a rapid intravenous infusion of 10 ml/kg of 0.9% sodium chloride solution
- If a child remains shocked after the first rapid intravenous infusion: immediately give another rapid intravenous infusion of 10 ml/kg of 0.9% sodium chloride solution and consider possible causes of shock other than dehydration
- Consider consulting a paediatric intensive care specialist if a child remains shocked after the second rapid intravenous infusion
- When symptoms and/or signs of shock resolve after rapid intravenous infusions, start rehydration with intravenous fluid therapy
- If intravenous fluid therapy is required for rehydration:
- Use an isotonic solution, such as 0.9% sodium chloride, or 0.9% sodium chloride with 5% glucose, for both fluid deficit replacement and maintenance
- For those who required initial rapid intravenous fluid boluses for suspected or confirmed shock, add 100 ml/kg for fluid deficit replacement to maintenance fluid requirements, and monitor the clinical response
- For those who were not shocked at presentation, add 50 ml/kg for fluid deficit replacement to maintenance fluid requirements, and monitor the clinical response
- Measure plasma sodium, potassium, urea, creatinine and glucose at the outset, monitor regularly, and alter the fluid composition or rate of administration if necessary
- Consider providing intravenous potassium supplementation once the plasma potassium level is known
- Attempt early and gradual introduction of oral rehydration therapy during intravenous fluid therapy; if tolerated, stop intravenous fluids and complete rehydration with oral rehydration therapy
- If intravenous fluid therapy is required in a child presenting with hypernatraemic dehydration:
- Obtain urgent expert advice on fluid management
- Use an isotonic solution such as 0.9% sodium chloride, or 0.9% sodium chloride with 5% glucose for fluid deficit replacement and maintenance
- Replace the fluid deficit slowly – typically over 48 hours
- Monitor the plasma sodium frequently, aiming to reduce it at a rate of less than 0.5 mmol/l per hour.
- After rehydration:
- Encourage breastfeeding and other milk feeds
- Encourage fluid intake
- In children at increased risk of dehydration recurring, consider giving 5 ml/kg of ORS solution after each large watery stool. These include:
- children younger than 1 year, particularly those younger than 6 months
- Infants who were of low birth weight
- Children who have passed more than five diarrhoeal stools in the previous 24 hours
- Children who have vomited more than twice in the previous 24 hours
- Restart oral rehydration therapy if dehydration recurs after rehydration
- Calculating fluid maintenance:
- Maintenance fluid volumes should be calculated using the Holliday – Segar formula (the traditional method of calculating fluid volume in children in the UK):
- 100 ml/kg/day (4 ml/kg/hr) for the first 10 kg body weight PLUS
- 50 ml/kg/day (2 ml/kg/hr) for the next 10 to 20 kg PLUS
- 20 ml/kg/day (1 ml/kg/hr) for each additional kilogram above 20 kg.
- Maintenance fluid volumes should be calculated using the Holliday – Segar formula (the traditional method of calculating fluid volume in children in the UK):
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- Biochemistry
- Blood Gases
- Haematology
| Biochemistry | Normal Value |
|---|---|
| Sodium | 135 – 145 mmol/l |
| Potassium | 3.0 – 4.5 mmol/l |
| Urea | 2.5 – 7.5 mmol/l |
| Glucose | 3.5 – 5.0 mmol/l |
| Creatinine | 35 – 135 μmol/l |
| Alanine Aminotransferase (ALT) | 5 – 35 U/l |
| Gamma-glutamyl Transferase (GGT) | < 65 U/l |
| Alkaline Phosphatase (ALP) | 30 – 135 U/l |
| Aspartate Aminotransferase (AST) | < 40 U/l |
| Total Protein | 60 – 80 g/l |
| Albumin | 35 – 50 g/l |
| Globulin | 2.4 – 3.5 g/dl |
| Amylase | < 70 U/l |
| Total Bilirubin | 3 – 17 μmol/l |
| Calcium | 2.1 – 2.5 mmol/l |
| Chloride | 95 – 105 mmol/l |
| Phosphate | 0.8 – 1.4 mmol/l |
| Haematology | Normal Value |
|---|---|
| Haemoglobin | 11.5 – 16.6 g/dl |
| White Blood Cells | 4.0 – 11.0 x 109/l |
| Platelets | 150 – 450 x 109/l |
| MCV | 80 – 96 fl |
| MCHC | 32 – 36 g/dl |
| Neutrophils | 2.0 – 7.5 x 109/l |
| Lymphocytes | 1.5 – 4.0 x 109/l |
| Monocytes | 0.3 – 1.0 x 109/l |
| Eosinophils | 0.1 – 0.5 x 109/l |
| Basophils | < 0.2 x 109/l |
| Reticulocytes | < 2% |
| Haematocrit | 0.35 – 0.49 |
| Red Cell Distribution Width | 11 – 15% |
| Blood Gases | Normal Value |
|---|---|
| pH | 7.35 – 7.45 |
| pO2 | 11 – 14 kPa |
| pCO2 | 4.5 – 6.0 kPa |
| Base Excess | -2 – +2 mmol/l |
| Bicarbonate | 24 – 30 mmol/l |
| Lactate | < 2 mmol/l |
