Thank you for your query
Firstly it will be helpful to know the details of why this kidney
is functioning 45%. I suggest you consult a pediatric surgeon. At times the damage may be due to an ongoing cause and if it can be averted then your child might get away without a transplant. But the pediatric surgeon needs to evaluate further for details. A transplanted kidney has a life of 10-20 years. So when it is done for an older person it works out fine. In children it is done only when we think that the life expectancy without a transplant is lesser than that. So actually it does not curtail one's life. It prolongs it from the already curtailed life due to the disease. But in children 10-20 years is not enough. That is why all this rumors regarding transplant. But we never know. It may last longer. And then we can think of a repeat transplant or alternative measures at that stage too. So if required transplant is life saving and life prolonging.
Hope that helps
God bless you