Abstract:

【Abstract】 Objective  To analyze the causes of acquired Fanconi syndrome(FS) and chronic renal damage due to prolonged use of adefovir dipivoxil(ADV) in low dose for hepatitis B, and suggest early diagnosis of ADV-induced FS and preventive measures for nephrotoxicity. Methods  The data were collected in 5 cases of FS confirmed in our hospital between January 2008 and 2013, and the clinical manifestations and therapy were analyzed. Results  Generally, the five patients received ADV in dose of 10 mg/d and average medication of 42.6 months. The FS symptoms averagely developed at 35.4 months. Clinical pictures were progressive systemic bone and joint pain, and 2 cases showed increased nocturnal urination frequencies. Serum phosphorus level was decreased to a certain extent in the 5 patients, in whom 3 had hypouricemia. Reduced estimated glomerular filtration rate(eGFR) was seen in the 5 cases, and increased alkaline phosphatase(ALP) in 4. Positive urine protein and abnormal glucose in urine were respectively found in 4 and 3 cases. Three patients were misdiagnosed as primary osteoporosis by dual-energy X-ray absorptiometry. After ADV withdrawal and replacement with entecavir in dose of 0.5 mg/d combined with oral neutral phosphate solution, alfacalcidol and calcium, bone pain was released in the 5 patients in 3 to 10 months, and blood phosphorus level restored to normal in 1 to 3 months. Hypouricemia was reversed in 2 of the 3 cases at the first and the eleventh month, and increased ALP was corrected in 2 of the 4 cases at the first and the twelfth month. Urine protein disappeared in 2 cases at the fifth and the twelfth month after ADV withdrawal, and another 2 cases with abnormal urine glucose were recovered in 4 and 8 months. Conclusion  Low-dose ADV can induce Fanconi syndrome. Patients, particularly those of the aged, with drinking habit or chronic diseases, needing prolonged use of ADV should be regularly monitored for the levels of serum phosphorus and ALP as well as renal function and routine urine test findings. Once renal damage occurs, ADV should be withdrawn in timely fashion and therapy regime may be replaced by other antiviral drugs with oral neutral phosphate solution, or prolonged ADV medication interval is decided by eGFR level.

Key words: Fanconi syndrome, Adefovir dipivoxil, Chronic Kidney Disease