The Hands-on Guide to Practical Paediatrics

Rebecca Hewiston
Caroline Fertleman


Scenario 1: Diarrhoea and vomiting

Jodie Green is a 5-year-old girl who presents to the emergency department with a history of diarrhoea and vomiting. Her details are as follows:

Name: Jodie Green
DOB: 21/6/2008
Address: 5 Bow Street, London
Hospital number: 12345678
NHS number: 0987654321

Her weight today is 19 kg (you don't have a recent previous weight on record for her). Her mother tells you that she has been passing much less urine than normal today and is more sleepy than her normal self. She has no known allergies and no significant past medical history.

On examination Jodie is sleeping initially but wakes easily and is then alert. Her capillary refill time is less than 2 sec, and all of her observations are within normal range for her age. Her mouth appears slightly dry, but she has a normal skin colour.

  • 1. Prescribe an appropriate initial fluid regime for Jodie. (You can print the blank drug chart provided to do this.)

    Correct answer:
    From this description Jodie appears to be showing signs of clinical dehydration but has no signs of shock (see Box 7.3 for more details). It is most appropriate in this situation to prescribe a trial of oral fluid replacement. Oral fluids should be replaced over a period of 4 hours. Normal maintenance requirements = 10 × 100 + 9 × 50 = 1450 mL
    Replacement required:
    Method 1
    An additional 50 mL/kg is needed for children with clinical dehydration 50 mL/kg × 19 kg = 950 mL
    Method 2
    1 mL fluid loss = 1 g weight loss. The clinical signs are consistent with 5% dehydration (loss of 5% of body weight due to dehydration). 5% × 19 kg = 0.95 kg = 950 g; therefore, 950 mL of additional fluid is required.
    Maintenance hourly rate = 1450/24 = 60.42 mL/hour
    Replacement (orally over 4 hours) hourly rate = 950/4 = 237.5 mL/hour
    Total hourly rate for first 4 hours = 60.42 + 237.5 = 298 mL
    Every 10 minutes = 298/6 = 49.66; therefore, prescribe 50 mL of oral rehydration salts to be given every 10 minutes for the first 4 hours.
    See the model answer prescription chart to check your answer – all personal details, allergies, date of admission and weight MUST be filled in.

  • 2. You return to reassess Jodie after 40 minutes and she has not been able to tolerate any of the oral fluid replacement. Her clinical condition is unchanged on reassessment. Her blood results are now available and you note that all of her electrolyte values are within normal range. Alter your prescription accordingly.

    Correct answer:
    Given that Jodie has not been able to tolerate oral replacement, she will need intravenous (IV) fluids. If replacing fluid intravenously, this should normally been done over 24 hours (unless the child is hyponatraemic, has diabetic ketoacidosis or heart failure in which case IV fluid must be given more slowly and replacement given over 48 hours).

    Maintenance = 1450 mL
    Replacement = 950 mL
    Total in 24 hours = 1450 + 950 = 2400 mL
    Hourly rate = 2400/24 = 100 mL/hour

    See the model chart for how this should be written on the drug chart. Note that the oral prescription must be crossed off and signed before prescribing the IV fluids. Also, in paediatrics, IV fluids are normally only available in 500-mL bags; therefore, the prescription on the model chart will only last for 5 hours. You can write up prescriptions for several bags if simply prescribing maintenance fluids, but in this case it is advisable to only prescribe one bag as the child will need to be reassessed and the fluid regime adjusted accordingly after 5 hours.

  • 3. The nurse calls you to say that Jodie is complaining of abdominal discomfort. You go to assess her and find that her abdomen is soft and non-tender, her capillary refill time is less than 2 sec and all of her observations are within normal range. You have no reason to suspect a surgical cause. Prescribe appropriate analgesia for Jodie.

    Correct answer:
    Given that Jodie is having only mild abdominal discomfort, it is probably appropriate at this stage to simply prescribe analgesia 'as required'. In the BNFC, oral paracetamol is now listed as a set dose for different age bands. For children aged 4–6 years, the dose is 240 mg every 4–6 hours. If Jodie is unable to tolerate oral analgesia, you can prescribe paracetamol PR instead but the dose is different (250 mg in this case).

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