The use of Renastep™ as part of the dietary management of Acute Kidney Injury (AKI) | Case Study

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Case study describing the use of Renastep as on oral nutritional supplement as part of the dietary management of a patient with  Acute Kidney Injury (AKI).

Age:16 years

Gender: Female

Acute Kidney Injury (AKI) with hypercalcaemia. Background of Trisomy 21 and oral aversion.

Relevant History: 
Patient was admitted following routine blood tests having been found to be in AKI. At the time of admission it was unknown if there was a background of Chronic Kidney Disease (CKD) or evolving AKI with unknown cause. The patient was given IV fluids, with serum and urinary investigations. 


  • Weight on admission: 27.3kg <0.4th centile* 
  • Current weight: 36.7kg 2nd centile*
  • Height on admission: 128cm 0.4th centiles*
  • Current height: 131.2cm 0.4th-2nd centile*

Feeding history:
Only managing porridge with milk and the occasional yogurt at school. Fluid intake is poor.

Meet energy and protein requirements whilst managing potassium and phosphate intake by reducing the patients intake of cow’s milk and using Renastep and a juice based oral nutritional supplement (ONS) instead.

Nutritional Requirements: 
EAR based on weight on admission = 1201kcal/day
EAR based on ideal body weight of 55.3kg = 2430 kcals/day

Protein: 45.4g/day 
12-20 mmol Ca/day

The patient was regularly reviewed in clinic; she was keen to take more porridge at home and had started taking yogurts at school. Her kidney function was improving; her serum potassium and phosphate levels had normalised. Her family were making 5 bowls of porridge per day for her; 3 bowls made with 125mls of Renastep per bowl, 1 with juice-based ONS, and 1 with cow’s milk.

Estimated Dietary Intake: 1398kcal, 38g protein, potassium 117mmol, phosphate 11.3mmol, calcium 19.5mmol.

It was felt that the patient could eat more so the family were advised to make any additional bowls of porridge with a non-calcium-fortified plant-based milk alternative. 

Six months after admission: 

  • Once the patients serum potassium and phosphate levels normalised, Renastep was discontinued.
  • Cow’s milk and yogurts have been increased to meet LRNI for calcium. 
  • Non-calcium fortified plant-based milk alternatives continue.

Estimated Dietary Intake: 1590kcal, 51g protein, 25.4mmol potassium, 22mmol phosphate, 22mmol calcium

  • The use of Renastep enabled a reduction in potassium and phosphate intake which meant the patients serum potassium and phosphate levels returned to be within the reference range. 
  • Renastep is 2kcal/ml which resulted in energy and protein being provided whilst limiting potassium and phosphate intake – this was an ideal way to provide nutrition support for this patient. 
  • Renastep can be taken as a drink, added to foods or used in recipes. .
  • Renastep is convenient and easy to use.