Renal amyloidosis and renal failure--a novel complication of the SAPHO syndrome

SAPHO syndrome: current clinical, diagnostic and treatment approaches

This review provides an overview of SAPHO (Synovitis, Acne, Pustulosis, Hyperostosis, and Osteitis), a rare autoinflammatory disease that primarily affects bones, skin, and joints. We conducted a search on Medline/PubMed using keywords such as SAPHO syndrome, chronic recurrent multifocal osteitis/osteomyelitis, and related terms. SAPHO syndrome is rare, with a reported frequency of 1 in 10,000 in the Caucasian population. However, the actual incidence of SAPHO syndrome is unknown, and the incidence of the disease is likely higher. The pathogenesis of SAPHO syndrome remains incompletely understood. Current evidence suggests that SAPHO results from a complex interplay between immune dysregulation, genetic susceptibility, and environmental factors. It's not clear if SAPHO syndrome is an autoimmune disease or an autoinflammatory disease, but current evidence suggests that it's more likely an autoinflammatory disease because of things like neutrophil hyperactivity, fewer natural killer (NK) cells, high levels of interleukin (IL)-1, and a good response to treatments that block IL-1. Osteo-articular (OA) involvement is a key clinical feature of SAPHO. It affects the anterior chest wall, axial skeleton, peripheral joints, mandible, long bones of the extremities, and pelvis. Dermatological involvement is a common target in SAPHO, with lesions observed in 60-90% of cases. Common skin lesions include psoriasis and acne, with hidradenitis suppurativa and neutrophilic dermatoses being less commonly seen. Other clinical findings include constitutional symptoms caused by systemic inflammation, such as fever, weight loss, and fatigue. There is no specific laboratory finding for SAPHO syndrome. However, during active disease, there may be an increase in positive acute phase markers, such as erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), complement levels, mild leukocytosis, and thrombocytosis. Diagnosis is crucial for SAPHO syndrome, which lacks a specific diagnostic finding and is often underrecognized. A comprehensive evaluation of a patient's medical history and physical examination is crucial. Treatment options include non-steroidal anti-inflammatory drugs (NSAIDs), corticosteroids, conventional and synthetic disease-modifying agents (cDMARDs and sDMARDs), biological therapies, bisphosphonates, and antibiotics. Biological treatments have emerged as a viable alternative for SAPHO patients who do not respond to conventional treatments.

Systemic Amyloidosis with Renal Failure: A Challenging Diagnosis of SAPHO Syndrome

Synovitis, acne, pustulosis, hyperostosis and osteitis (SAPHO) syndrome is a rare, unrecognized and chronic inflammatory disorder characterized by distinct cutaneous and osteoarticular manifestations. Renal complications are uncommon. We describe the unusual case of a patient with severe refractory and chronic hidradenitis suppurativa (HS) that progressed to chronic renal failure due to secondary amyloidosis, presenting with mandibular pain and renal failure. The challenging diagnosis of SAPHO syndrome was made. The purpose of this case report is to emphasize the need for vigilance, timely recognition and multidisciplinary treatment. The fundamental management of AA amyloidosis and SAPHO syndrome requires an individualized approach with control of the underlying inflammatory disease.

LEARNING POINTS

Systemic amyloidosis is a serious but rare complication of chronic inflammatory disorders such as hidradenitis suppurativa and should be periodically considered.SAPHO syndrome should be suspected in patients with cutaneous and osteoarticular manifestations, and is a challenging diagnosis with exclusion of neoplastic, autoimmune and infectious diseases.The cornerstone of management of AA amyloidosis is vigilance, timely recognition and sometimes aggressive immunosuppressive treatment.

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

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.

Renal dysfunction due to hydronephrosis by SAPHO syndrome: a case report

Synovitis, Acne, Pustulosis, Hyperostosis, Osteitis (SAPHO) syndrome shows varied pathological symptoms. This is the first report of hydronephrosis due to the mechanical compression of bilateral ureters as a result of SAPHO syndrome. From our experience, MRI is the most useful imaging examination to check the upper urinary tract in SAPHO syndrome.

A hidradenitis suppurativa related SAPHO case associated with features resembling spondylarthropathy and proteinuria

We present a 53-year-old man with synovitis-acne-palmoplantar pustulosis-hyperosteosis-osteitis (SAPHO) syndrome who is HLA-B27 positive with a history of uveitis and complicated by proteinuria and osteoporosis. Interesting, yet unreported features of SAPHO syndrome and the etiology of proteinuria are further discussed.

SAPHO syndrome: a long-term follow-up study of 120 cases

OBJECTIVE

To assess the long-term outcome of the synovitis, acne, pustulosis, hyperostosis, osteitis (SAPHO) syndrome.

METHODS

All patients with the SAPHO syndrome seen at our unit between 1974 and 1997 were identified. Follow-up was prospective from 1992 to 1997. Data before 1992 were analyzed retrospectively. Clinical symptoms, treatments and biological data, including erythrocyte sedimentation rate and C-reactive protein, were recorded at least yearly. When available, radiological data, HLA B27 status, and findings from bone or skin biopsy specimens were recorded. For each drug, an efficacy index (El) was determined as follows: "0" for less than 30% improvement, as judged by the patient, on horizontal visual analog scale, "0.5" for partial efficacy, and "1" for more than 60% improvement.

RESULTS

We identified 120 patients with the SAPHO syndrome (50 men, 70 women), of whom 102 patients were followed-up prospectively after 1992; 3 of these 102 patients were lost to follow-up. Six patients also had Crohn's disease, and three had ulcerative colitis. Except for a significant association of palmoplantar pustulosis (PPP) or psoriasis vulgaris (PV) with axial osteitis (P = .007), the dermatologic presentation had no significant influence on rheumatic symptoms (ie, osteitis or arthritis, peripheral or axial). The HLA B27 antigen was not significantly associated with a particular pattern of distribution of arthritis or osteitis. No severe or disabling complications were noted. In the 47 patients followed-up for more than 5 years (mean, 9.5; range, 5 to 23), the mean number of osteitis or arthritis foci increased during follow-up from 1.57 to 1.91 and from 2.68 to 3.11, respectively. Nonsteroidal antiinflammatory drugs (NSAIDs) were prescribed in 113 of 120 (94%) patients, with a mean El of 0.67 (+/-0.39). Corticosteroid (CS) therapy was used in 23 patients, with a mean El of 0.67 (+/-0.42). Colchicine and sulfasalazine had a mean El of 0.36 (+/-0.44) and 0.16 (+/-0.30), in 28 and 18 patients, respectively. Methotrexate was given to 10 patients (6 with peripheral arthritis), with a mean El of 0.64 (+/-0.48). Doxycyclin (100 mg twice daily) was used in 20 patients, usually to treat osteitis, with a mean El of 0.26 (+/-0.42). Intraarticular injections of a CS or osmic acid were used in 27 patients, with a mean El of 0.77 (+/-0.35).

CONCLUSIONS

SAPHO syndrome is a relevant and stable entity, with a good long-term prognosis. NSAIDs and intraarticular injections (CS or osmic acid) most often alleviate rheumatic symptoms, but prednisone or methotrexate are sometimes necessary and appear globally helpful.