The Collaborative International Dictionary of English v.0.48:

Nephralgia \Ne*phral"gi*a\, Nephralgy \Ne*phral"gy\, n. [NL.
   nephralgia, fr. Gr. nefro`s 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.
   [1913 Webster]

WordNet (r) 3.0 (2006):

nephralgia
    n 1: pain in the kidney (usually felt in the loins)