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Kidney Biopsy Case Submitted by Dr. Troels Ring 

The patient is a 34 years old man, a tamil born in Sri Lanka, but refugee in Denmark since 10 years. His history is negative for familial diseases and earlier kidney disease, and for known severe infections including hepatitis, HIV, schistosomiasis and tuberculosis.

Smoking some 10 cigarettes and with a previous working history including lengthy employment at a tree goods fabrication plant, he presented in 1996 to the lung department with symptoms of coughing and a mild anemia with Hgb 11.6 g/dl (7.2 mM), a low MCV of 0.72, and leukocytes 8 * 109/l of which 10% were eosinophils.  Platelets 251 * 109/l. No sign of hemolysis, iron, folic acid and cobalamin normal. Hæmoglobin analysis disclosed no hemoglobinopathy. FEV1 was slightly decreased at 80% but examination including thoracic X-ray otherwise negative. Sputum examination for TB was negative, and skin tests disclosed no atopy. Arterial blood pH was 7.37 with a pCO2 of 35.2 mmHg and a bicarbonate of 20 mM indicating incomplete respiratory compensation to mild metabolic acidosis. Serum creatinin was elevated at 126 (mol/l (1.4 mg/dl), electrolytes normal, Calcium and phosphate normal, blood glucose normal.

Since then creatinine has slowly increased to 282 (mol/l (3.2 mg/dl), mild metabolic acidosis is still present (bicarbonate 20 mmol/l), urine with slight protein 0.5 g/l, a rare erythrocyte and a trace of glucose, a low urine pH of 5.5 but also low computed ammonium of only 5 mmol/l (from 0.5*(osmolality-(urea+2*(Na+K))) (with all entries in mmol/l). During the years he has had intermittently a slight increase in hepatic anzymes including aspartate-aminotransferase and gammaglutamyl-transferase, while alkaline phosphatase, bilirubin, INR, APTT, serum albumin, and cholesterol have been normal always.

IgG has been slightly elevated at 16.7 g/l (IgM and IgA normal), but no monoclonals seen in either blood or urine. Hæmoglobin has been stable. Serologic examination negative (ANA, ANCA, anti-GBM), tests for virus infections including hepatitis B and C, HIV, CMV negative. Normal thyroid function. Complement (C3c and C4) normal. Serum urate normal too.

Ultrasound exam of liver, pancreas and kidneys normal.

Presently his only complaint has been of a slight polakisuria. Cystoscopi negative, urine cytology likewise, and normal urological exam, too. His blood pressure has been normal all the time, last measured at 118/80 mmHg. He eats a mixed Danish-Tamil food which includes lots of fruits and vegetables. He has not been dieting, he has not eaten any food additions with unknown herbs, and he still has no medicine at all. He has not been on drugs.

Clinically the renal diagnosis was possible tubular disease with RTA and glucosuria and slight proteinuria and impaired renal function.

Kidney Biopsy showed 35 glomeruli of which 12 were partially or totally sclerosed. The resting glomeruli were normal by light microscopy and without immunofluorescence, and with normal appaearance on electron microscopy. The significant finding was an unusually high degree of nuclear pleomorphi in tubular epithelium, but without necroses and mitotic activity. Interstitially was noted mononuclear inflammatory reaction, particularly in areas close to sclerosed glomeruli. The vessels of all sizes appeared normal. Immunohistochemical examination for CMV virus was negative, too. Hence the pathologist interpreted the findings to indicate an interstital disease with a secondary glomerular destruction. No granulomas identified.

So, I believe the essential features are impaired kidney function, possibly from unknown tubular disease with eosinophilia and slight elevation of liver enzymes (unless they also indicate tubular disease, I believe I have seen that with gammaglutamyl transferase, at least, and value s are at most * 2 elevated). We have been puzzled by the appearance of the nuclei in tubular cells.

 

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