A man in his 30s with a history of type 1 DM and chronic
hypokalemia was referred to the renal clinic for investigation of CKD. His creatinine was 1.8g mg/dl. His DM was well controlled without any evidence of retinopathy. Urinalysis did not show any proteinuria
or hematuria. His renal biopsy showed
focal tubular atrophy, dystrophic calcification in the scattered tubules, and
did not have any signs of diabetic nephropathy. His renal biopsy findings were therefore attributed to
Hypokalemia can cause kidney damage if it persists for longer
than one month. Chronic hypokalemia can
cause non-specific vacuolar lesions in the epithelial vessels in the proximal
tubules. Typical renal biopsy will show
interstitial nephritis, fibrosis, tubular atrophy and cyst formation. The pathogenesis of hypokalemic nephropathy
is not clear. The hypotheses are: 1) complement activation and tubular cell
damage by hypokalemia induced renal ammonium production 2) stimulation of cell growth and proliferation by intracellular acidosis 3) increased production of growth
factors (VEGF, IGF-1) and cytokines by hypokalemia through an uncertain mechanism.
After further work-up, our patient was diagnosed with Giltelman
syndrome. He was
started on potassium replacement and his Cr has remained stable since then.