Fact-sheet: SAPHO syndrome


Updated on 06/15/2020 at 11:44 AM

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Definition

Synovitis Acne Pustulosis Hyperostosis Osteitis
Diagnostic criteria:

Major criterion:
- presence of chronic recurrent multifocal osteomyelitis (CRMO) or osteomyelitis due to Propionibacterium acnes

Minor criteria:

- Osteoarticular:

Acute or chronic arthritis

Aseptic osteitis (mono- or polyostotic)

- Cutaneous:

Palmoplantar pustulosis or pustular psoriasis (more common in women)

Acne fulminans or conglobata (more common in men)

Hidradenitis suppurativa

--> Diagnosis if one major criterion or 2 minor criteria

Clinical features

Involvement:

  • Osteoarticular: mainly articular (sternocostoclavicular region, spine, pelvis)
  • peripheral arthritis
  • peripheral enthesitis
  • Cutaneous: Palmoplantar pustulosis
  • Acne
  • Psoriasis
  • Digestive: Crohn disease
  • Ulcerative colitis

Possible but rare general signs: fever, weight loss, lethargy

Anecdotally: renal amyloidosis, osteosarcoma

Laboratory findings

There may be a biological inflammatory syndrome: elevated ESR and CRP, but the CBC is usually normal

Radiography

  • Sternocostoclavicular region: Osteitis (osteosclerosis)
  • Hyperostosis (bone hypertrophy, costoclavicular ligament ossification)
  • Erosions (sternoclavicular, manubriosternal)
  • Ankylosis (sternocostal)
  • Soft tissue swelling (possible thoracic outlet syndrome)
  • Spine: Spondylitis (osteosclerosis of the vertebral corners or bodies)
  • Paravertebral ossifications (parasyndesmophytes)
  • Spondylodiscitis (single or multilevel)
  • Pelvis: Osteitis (patchy osteosclerosis)
  • Ossifying enthesopathies
  • Sacroiliitis (unilateral)

CT

Hyperostotic inflammatory rheumatism

Sternocostoclavicular involvement:

- the most common and the most suggestive

- erosions

- osteitis: fibrillary bone sclerosis + thickened trabeculae

- ossification of the sternoclavicular ligament

- periosteal reactions

- soft tissue swelling --> sometimes marked ++ (differential diagnosis with an infectious etiology)

- ankylosis

Vertebral involvement: present in 30 to 50% of patients, isolated in 10% of cases. It affects the lumbar (54% of cases), thoracic (33%), and cervical (12%) segments and is often multifocal from the outset.

- enthesitis with erosion (peripheral part of the anterior longitudinal ligament and at the insertion of Sharpey's fibers) and hyperostosis (syndesmophytes)

- spondylitis: vertebral body sclerosis that may progress to an ivory vertebra appearance

- soft tissue involvement

Pelvic involvement:

- unilateral sacroiliitis ++ with extensive bone sclerosis on the iliac side

- little erosion

Temporomandibular involvement: highly suggestive ++

- unilateral osteitis

Other joint involvement is possible but less specific.

MRI

Same as CT, plus:

- bone marrow edema with T2 PD FatSat hyperintensity in osteitis

- fatty replacement and T1 and T2 PD FatSat hyperintensity of old spondylitis lesions

Management

NSAIDs as first-line therapy: relieve pain and reduce inflammation

Other therapies: injectable bisphosphonates (axial involvement) and anti-TNFa agents (peripheral involvement)

Differential diagnosis

- Septic arthritis

- Other inflammatory rheumatic diseases