Osteomalacia as a presenting manifestation of Sjögren's syndrome

Osteomalacia is still common in Morocco, where the leading causes are nutritional deficiencies followed by intestinal diseases. Osteomalacia rarely occurs as the first manifestation of a renal tubule disorder due to a connective tissue disease such as Sjögren's syndrome. The case of a 40-year-old woman who presented with a five-year history of generalized bone pain, severe weight loss and a waddling gait is reported. She had low levels of serum phosphate (0.74 mmol/L), serum calcium (1.97 mmol/L), and urinary calcium (1.22 mmol/24 h). Serum alkaline phosphatase was 210 IU/L. Roentgenograms showed Looser's zones (right femoral neck, sixth and seventh right ribs). There was bilateral parotid gland enlargement, dryness of the mouth, nose and eyes, and bilateral punctate keratitis. A lip biopsy showed changes corresponding to stage II of the Chisholm and Mason classification. Tests for rheumatoid factor (latex and Waaler-Rose) and antinuclear factor were negative. The alkaline reserve was 18 mmol/L, serum potassium was 3.5 mmol/L, serum chloride was 112 mmol/L and urinary pH was 6.5. A renal biopsy showed tubulointerstitial lesions, lymphoplasmocytic infiltrates and interstitial sclerosis with patchy tubular atrophy. The patient was given bicarbonates, high-dose vitamin D followed by 1-alpha-hydroxycholecalciferol (0.3 microgram/d), and calcium (1 g/d). Follow-up was 42 months at the time of this writing. The role of tubular disorders in the genesis of osteomalacia is discussed, and the renal manifestations of Sjögren's syndrome are reviewed.