Source : Webster's Revised Unabridged Dictionary (1913)

Nephralgia \Ne*phral"gi*a\, Nephralgy \Ne*phral"gy\, n. [NL.
   nephralgia, fr. Gr. ? a kidney + ? pain: cf. F.
   n['e]phralgie.] (Med.)
   Neuralgia of the kidneys; a disease characterized by pain in
   the region of the kidneys without any structural lesion of
   the latter. --Quain.

Source : WordNet®

nephralgia
     n : pain in the kidney (usually felt in the loins)