A case of synovitis, acne, pustulosis, hyperostosis, and osteitis (SAPHO) syndrome complicated by IgA nephropathy with nephrotic syndrome

Abstract

A 62-year-old man visited our hospital with a mild sore throat, high-grade fever, and clavicular pain. Seven years earlier, he had been diagnosed with synovitis, acne, pustulosis, hyperostosis, and osteitis (SAPHO) syndrome. His clavicles were tender and remarkably swollen. Also noted was marked pitting edema in the lower extremities and pustulosis on the palms and soles of the feet. Laboratory studies on admission showed an elevated white cell count (23,400/μl) and serum C-reactive protein level (24.4 mg/dl). Urinalysis revealed proteinuria (2+) and occult blood (3+) with numerous dysmorphic red blood cells and hyalin casts. The patient was diagnosed with recurrence of his SAPHO syndrome and started on oral glucocorticoid therapy. By day 9 after admission, he had gained 16 kg in body weight, and his proteinuria (6.4 g/day) and serum creatinine level (2.3 mg/dl) were elevated. Renal biopsy revealed mesangial proliferative glomerulonephritis with deposition of IgA and C3 in the mesangial area and along the capillary walls. The patient was diagnosed with IgA nephropathy accompanied by nephrotic syndrome. With oral prednisolone therapy, his fever, clavicular pain, and proteinuria were gradually relieved. The clinical course in this case suggests the onset of nephrotic syndrome with IgA nephropathy was associated with the recurrence of the patient's SAPHO. To our knowledge, this is the first reported case of SAPHO-associated IgA nephropathy.

Keywords: IgA nephropathy; Nephrotic syndrome; SAPHO syndrome; Tonsillar infection.

Fig. 1

Manifestation of musculoskeletal and cutaneous lesions. a Computed tomography revealed osteolysis of the sternoclavicular joints. b The skin around the clavicles was flushed and swollen. c Pustulosis was present on the soles of the feet

Fig. 2

Renal histology and immunofluorescent examination. a, b Glomerulus showing mild mesangial proliferation and segmental endocapillary proliferation. Deposition of IgA (c) and C3 (d) in the mesangial area and along the capillary wall. a ×100, b–d ×200

Fig. 3

Clinical course. PSL prednisolone, CRP C-reactive protein, SCr serum creatinine