[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.

[Injuries of the sternoclavicular joint]

Injuries of the sternoclavicular joint (SCJ) are rare accounting for 3% of all injuries to the shoulder girdle and are often overlooked. The SCJ is surrounded by tight ligamentous structures, thus substantial energy with corresponding force vectors is needed to cause dislocation. Causative are mostly high-energy traumas. Anterior dislocation is most common but in rare cases potentially life-threatening posterior dislocation occurs, which requires immediate reduction. The established gold standard is 3D reconstruction in contrast-enhanced computed tomography (CT) for depiction of neurovascular structures. Low-grade instability can initially be treated conservatively. For unsuccessful attempts at reduction, high-grade instability and chronic instability various surgical techniques are established. Next to retentive augmentation with suture materials, in acute cases with chronic instability biological tendon augmentation is preferred. In cases of posttraumatic instability arthritis SCJ resection with or without additive biological augmentation can be carried out. Various study groups have shown good to very good midterm outcome.

Sternocostoclavicular Hyperostosis: An Ill-Recognized Disease

Sternocostoclavicular hyperostosis (SCCH) is an ill-recognized, rarely diagnosed disease. Today, SCCH is widely considered part of the synovitis, acne, pustulosis, hyperostosis and osteitis (SAPHO) syndrome. SCCH develops over years with intermittent attacks of pain, swelling, and reddening of the sternocostoclavicular region. The disease causes progressive hyperostosis, fusion of the sternocostoclavicular joints, and soft tissue ossification. SCCH is chronic, non-malignant, and occurs predominantly bilaterally in middle-aged women. The incidence of the disease is unknown. We present a case of isolated SCCH, where chest radiographs showed a clear development of bilateral disease over the course of more than a decade. Whole-body bone scintigraphy was performed and was suggestive of SCCH. The diagnosis was established as late as 14 years from the onset of symptoms. During this period, the patient underwent several inconclusive examinations, resulting in a delay of diagnosis and in prolonged and aggravated symptoms. With this case report, we want to draw attention to SCCH and the importance of early diagnosis of the disease.

Syndromes with chronic non-bacterial osteomyelitis in the spine

Chronic non-bacterial osteomyelitis (CNO) has been known for over of 40 years. It is an underrecognized entity due to the low number of described cases and poor propagation awareness of the problem. Chronic non-bacterial osteomyelitis is usually confused with infectious spondylodiscitis or malignant lesions, both primary and metastatic. Failing to consider CNO as one of possible lesions of the spine among an array of differential diagnoses may lead to a prolonged ineffective treatment increasing treatment-related morbidity. In this paper the authors describe these two syndromes, with a possible autoimmune background – chronic recurrent multifocal osteomyelitis (CRMO) and SAPHO syndrome – that include CNO being among the manifestations. The authors present the spinal symptomatology of CNO for both syndromes published so far to help spine clinicians organize the information for better usage in everyday clinical practice.