A 72-year-old man presented to the emergency department complaining of asthenia and anorexia in the last months, accompanied by a weight loss of about 10 kilos in the last year.
Relevant personal history included: type II diabetes mellitus of ten years of evolution without angiopathic, chronic arterial hypertension of twelve years of evolution with good ambulatory control and right renal colic x previous non-obstructive lithiasis.
Its usual treatment consists of metformin (850 mg), gliclazide (30 mg), acetylsalicylic acid (100 mg) and calcium (20 mg), all in a single daily dose.
On admission she had a blood pressure of 138/79 mm Hg and no relevant findings on physical examination.
Laboratory tests showed deterioration of renal function (serum creatinine 3.4 mg/dL) compared to the previous one-year control (serum creatinine 1.3 mg/dL), with no significant ionic or acid-base alterations.
The study of calcium-phosphorus metabolism, lipid profile, liver and pancreatic enzymes is normal.
Urinary analysis showed mild proteinuria (0.2 g/24 hours) predominantly tubular, without microhematuria or presence of cylinders or crystals in the sediment.
He had normocytic normochromic anemia without alterations in the rest of series.
Immunological study was performed including complement, antinuclear antibodies, neutrophil anticytoplasmic, anti-Ro, anti-La and rheumatoid factor, as well as serum and urinary proteinogram and tumor markers at 19mL, all of them normal.
An abdominal ultrasound showed kidneys of normal size and morphology and an atrophic pancreas with multiple diffuse calcifications.
These findings are later confirmed by abdominal computerized axial tomography and echoendoscopy, in which there is also evidence of a pursed dilatation of the Wirsung duct, without space occupying lesions.
A renal biopsy showed normal morphology of the granules without lesions at the tubulointerstitial level and involvement with moderate interstitial infiltrate of acute lymphocytic proliferation, accompanied by signs of acute tubular necrosis
In the interstitium and in the interior of numerous tubules, irregular intracellular crystals are observed, presenting birefringence with polarized light, with morphological characteristics compatible with crystals.
Urinary oxalic levels were 49 mg/24 hours (normal range 7-44 mg/24 hours).
The quantification of elastase in faeces was < 100 mcg/g (normal value > 200 mcg/g).
Treatment is initiated with oxalic chelators and bile salts, despite which the patient remains without changes in renal function two months later.
