Multiple osteoporotic fractures in a patient with CKD stage G3b

A previously healthy 54-year-old Japanese woman presented with pain in her right chest and left inguinal area after lifting a heavy object. She also had left chest pain 4 months earlier associated with coughing. She was not obese, and her blood pressure was 104/56 mm Hg. On physical examination, she had bilateral rib tenderness and otherwise normal results. Chest X-rays revealed multiple healing rib fractures, and bone scintigraphy showed increased uptake in the left pelvic bone and bilateral ribs (Figure 1). Her blood cell counts were normal. The blood laboratory findings were as follows: total protein, 7.3 g/dl; albumin, 3.8 g/dl; creatinine, 1.35 mg/dl (estimated glomerular filtration rate 32.8 ml/min per 1.73 m2); sodium, 137 mEq/l; potassium, 3.3 mEq/l; chloride, 110 mEq/l; calcium, 8.7 mg/dl; phosphorus, 2.5 mg/dl; alkaline phosphatase, 418 U/l; intact parathyroid hormone, 85 pg/ml; and venous HCO3−, 21 mmol/l. The urinalysis showed a pH of 6.5 and negative findings for blood, protein, and sugar. The urinary Bence Jones protein was negative. Sonography showed atrophy of the bilateral kidneys, with a size of 8.5 cm. An arterial blood-gas analysis revealed the following values: pH, 7.34; PCO2, 36 mm Hg; PO2, 87 mm Hg; and HCO3−, 19 mmol/l. She showed a positive response for the antinuclear antibody test, with a normal complement level. She also showed positive test results for anti-SSA and anti-SSB antibodies, positive criteria for Schirmer’s test, and focal lymphocytic sialoadenitis in a lip biopsy. She was diagnosed as having Sjogren syndrome with renal tubular acidosis (RTA), and a renal biopsy was performed (Figure 2). After treatment with corticosteroids and potassium citrate combined with sodium citrate, her symptoms disappeared and her renal function improved. Distal RTA should be considered in patients with hyperchloremic metabolic acidosis and multiple bone fractures.