Lithium Carbonate and nephrologist

I have been taking some form of Lithium Carbonate since 1972. About one year ago after taking a routine blood test prescribed by my psychiatrist, I was told my creatine level was somewhat spiked. The psych referred me to a nephrologist. After examination by the nephrologist, I was told I had 50% less kidney function and he believed to be my long-time intake of lithium carbonate products. The nephrologist also informed me that I would not regain function and perhaps suffer further loss of kidney function which would require dialysis. My psych immediately took me off Lithium and I suffered the extreme side effects of replacement meds like Carbamabazine (generic Tegretol).