Clinical Features, Early Diagnosis And Early Treatment Of Hypophosphatemic Osteomalacia Due To Fanconi’s Syndrome Secondary To Adefovir Dipivoxil

ObjectsTo investigate the clinical characteristics, early diagnosis and treatment approaches for the hypophosphatemic osteomalacia due to Fanconi’s syndrome induced by adefovir dipivoxil therapy for chronic hepatitis B.MethodsWe collected the clinical data of 5 cases of patients with chronic hepatitis B developed hypophosphatemic osteomalacia due to Fanconi’s syndrome after administration of adefovir dipivoxil was collected and searched referring reports before. The clinical features, present diagnosis and treatment approaches of Hypophosphatemic osteomalacia induced by low dose of adefovir dipivoxil among patients with chronic hepatitis B was summarized and analyzed.ResultsWe hospitalized the 5 male cases during 2009-2014. They were aged 30-68 years. Four of them were hospitalized with generalized bone pain, one presented paroxysmal muscle weakness. All of them were administrated with adefovir dipivoxil for antiviral treatment of chronic hepatitis B. Symptoms occurred after taking adefovir dipivoxil for 2-6 years. Laboratory investigation results performance outstanding in hypophosphataemia (0.32-0.67 mmol/L), hypokalemia(61-439μmol/L), low blood uric acid(2.5-3.8 mmol/L), glycosuria(82-132μmol/1) and proteinuria. Dual-energy X-ray absorptiometry (DXA) showed decrease of bone mineral density (BMD). Whole-body 99m-Tc-methylene diphosphonate bone scintigraphy showed increased uptake in several lotus. They all got normal renal function and without history of diabetes and hypertension before taking adefovir. They also didn’t take drugs that can do harm to kidney. The adefovir-induced hypophosphatemic osteomalacia due to acquired renal Fanconi’s syndrome was made. Adefovir was therefore ceased, and entecavir was commenced at a daily dose of 0.5 mg instead. In order to correct the calcium/phosphate metabolism, we started all patients on calcium supplement and calcitriol. For patients with hypokalemia, we administrated potassium treatment. All the 5 cases got symptom relief and hypophosphataemia were correct.Conclusions 1. Long-term use (>6 months) of adefovir dipivoxil at 10 mg daily, may be nephrotoxic and cause Fanconi’s syndrome and hypophosphataemic osteomalacia, especially in Asian male.2. It’s often onset with bone and joint pain, hypouricemia, increased levels of alkaline phosphatase, urinary phosphate wasting, glycosuria and bone densitometry displayed abnormally low bone bone mass.3. Reducing the dose or stop of adefovir, taking supplementation with elemental phosphate and calcium, and initiating the administration of activated vitamin D were most commonly employed therapy to date.