ACUTE DIARRHOEA AND VOMITING
History
Luca is a 24-month-old boy with Down’s syndrome, brought to the A&E department by his mother. He has had diarrhoea and vomiting for 1 day. In the last 8 hours, he has drunk 200 ml milk, vomited five times and passed six liquid stools. The vomit is not bilious and there is no blood or mucus in the stools. It has been hard to tell if he is passing urine because every nappy is soiled. He has no cardiac problems and no other medical problems except glue ear. There is no history of foreign travel. His two older siblings have recently had diarrhoea and vomiting.
Examination
He is miserable and lethargic. His heart rate is 120 beats/min, respiratory rate is 25 breaths/min, and his temperature is 37.7C. He has dry mucous membranes, his eyes are slightly sunken, his skin turgor appears normal and his capillary refill time is less than 2 s. His abdomen is soft with no masses palpable. His weight is 11 kg (50th centile on the Down’s syndrome growth chart). An oral fluid challenge is commenced in the emergency department. He drinks 60 ml of electrolyte solution over 2 hours and vomits once on the floor. He does not pass urine into a urine bag during this period.
Questions
• What is the most likely diagnosis?
• How dehydrated is this child?
• How would you manage this child now?
• How would you calculate the fluid requirements for this child over the next 24 hours?
Medicine
The most likely diagnosis is viral gastroenteritis, probably due to rotavirus. This fits with the acute onset and the fact that his siblings have also been unwell. This child is about 5 per cent dehydrated, which means that he has lost 5 per cent of his body weight as fluid. Signs of dehydration in children are shown in Table 26.1.
Table 26.1 Signs of dehydration in children
Mild Moderate Severe
(5 per cent) (5–10 per cent) (10 per cent)
Oral mucosa Dry Dry Dry
Eyes Normal Sunken Very sunken
Fontanelle Normal Sunken Very sunken
Skin turgor Normal Reduced Very reduced
Pulse Normal Fast Fast and weak
Capillary refill time Normal Prolonged Prolonged
Blood pressure Normal Normal Low
Urine output Normal Reduced Very reduced
Mental state Normal Lethargic Irritable or obtund
Management of mild-to-moderate dehydration should involve enteral rehydration (oral or nasogastric) whenever possible. This can be done with an appropriate electrolyte solution. After an initial 4-hour period of rehydration (when the fluid deficit is replaced), normal feeds can be resumed, although breast-feeding can be continued throughout. Intravenous rehydration is associated with a slower recovery and a longer hospital stay but is necessary if a child needs acute volume replacement for shock or is unable to tolerate enteral fluids. Luca should be admitted for a trial of nasogastric fluid therapy. If he does not tolerate this, he will probably need intravenous rehydration. This is calculated as follows: Fluid requirement for 24 hours maintenance correction of deficit replacement of ongoing losses Maintenance fluid 100 mL/kg for first 10 kg body weight 100 10 50 mL/kg for next 10 kg 50 1 20 mL/kg thereafter Total 1050 His fluid deficit is 5 per cent of body weight (5/100) 11 kg 0.55 kg. This is equivalent to 550 mL (1 mL of water weighs 1 g). Losses (stool and vomit) are calculated from the fluid balance chart and can be replaced at regular intervals. For this child, the total fluid requirement for the first 24 hours is calculated as follows: 1050 mL 550 mL losses 1600 mL losses This is equivalent to 67 mL/hour losses.
KEY POINTS
• Rotavirus is the most common cause of gastroenteritis in infants and young children.
• Clinical assessment of dehydration is based on multiple physical signs.
• Where possible, enteral rehydration with an electrolyte solution should be used for children with gastroenteritis.
• Fluid replacement must account for the deficit plus the maintenance requirement plus ongoing losses.
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