Acute renal failure is one of the most common indication to renal biopsy in elderly patients. As increasing age and comorbidities, histological patterns could be very different. Particularly, they cannot be classifiable in the common and very known histological entities. We report the case of an old patient who presented renal acute failure without any apparent plausible cause.
A 78-year old patient with a history of hypertension and atherosclerosis, was referred to our hospital for non-oliguric acute renal failure (ARF). At admission, clinical examination and blood pressure were normal. Laboratory data are expressed in table 1.
UCa (mEq/die)
Urine examination was not remarkable, CRP and ESR were normal. Immunological blood tests were negative. On ultrasound, both kidneys presented normal size; at doppler-ultrasound, renal arteries stenosis has been excluded. Thus, renal biopsy was performed. On light microscopy, 4/9 glomeruli were completely sclerotic, the remnants were normal. Tubular damage was remarkable: atrophy, acute tubular necrosis, tubulitis, interstitial inflammation with a giant cell reactions around calcium micro-deposits. We also found severe aterosclerosis and moderate arteriolar hyalinosis. At immunofluorescence, there were granular C3 deposits on vascular polus, Bowman'capsula and tubules. Electronic microscopy confirmed severe tubular damage with signs of intersitial and tubular inflammation.
On the basis of renal biopsy, we make diagnosis of acute renale failure secondary to acute tubular necrosis in patient with idiopathic ipocalciuric hypercalcemia.