Total body scintigraphy is useful to identify and determine the extent of bone lesions, and should be performed in all patients with suspected fibrous dysplasia.Children with fibrous dysplasia in the appendicular skeleton typically present with limp, pain, and/or pathologic fractures. Frequent fractures and progressive deformity may lead to difficulties with ambulation and impaired mobility. In the craniofacial skeleton, fibrous dysplasia may present as a painless “lump” or facial asymmetry. Expansion of craniofacial lesions may lead to progressive facial deformity. In rare cases, patients may develop vision and/or hearing loss due to compromise of the optic nerves and/or auditory canals, which is more common in patients with McCune-Albright syndrome associated growth hormone excess. Fibrous dysplasia commonly involves the spine, and may lead to scoliosis, which in rare instances may be severe. Untreated, progressive scoliosis is one of the few features of fibrous dysplasia that can lead to early fatality. Bone pain is a common complication of fibrous dysplasia. It may present at any age, but most commonly develops during adolescence and progresses into adulthood. Bone marrow stromal cells in fibrous dysplasia produce excess amounts of the phosphate-regulating hormone fibroblast growth factor-23 (FGF23), leading to loss of phosphate in the urine. Patients with hypophosphatemia may develop rickets/osteomalacia, increased fractures, and bone pain. Pathophysiology
Fibrous dysplasia is a mosaic disease resulting from post-zygotic activating mutations of the GNAS locus at 20q13.2-q13.3, which codes for the α subunit of the Gs G protein-coupled receptor. In bone, constitutive Gsα signaling results in impaired differentiation and proliferation of bone marrow stromal cells.
Schnitzler syndrome or Schnitzlers syndrome is a rare disease characterised by onset around middle age of chronic hives (urticaria) and periodic fever, bone pain and joint pain (sometimes with joint inflammation), weight loss, malaise, fatigue, swollen lymph glands and enlarged spleen and liver.Schnitzler syndrome is considered an autoinflammatory disorder and is generally treated with anakinra, which inhibits interleukin 1. This treatment controls the condition but does not cure it. Around 15% of people develop complications, but the condition generally does not shorten life. Classification
Schnitzler syndrome is a late-onset autoinflammatory disorder. Signs and symptoms
The typical onset is at around 55 years old, and the symptoms are recurrent hives, mostly on the torso and limbs, often with recurring fever, joint pain, bone pain, muscle pain, headache, fatigue, and loss of weight. Cause
As of 2017 the cause of the disease was not understood. Diagnosis
Blood tests show a high concentration of specific gamma-globulins (monoclonal gammopathy) of the IgM type. It almost always has light chains of the κ-type. A variant in which IgG is raised has been described, which appears to be one-tenth as common. The immunoglobulins may show up in the urine as Bence Jones proteins. Signs of inflammation are often present: these include an increased white blood cell count (leukocytosis) and a raised erythrocyte sedimentation rate and C-reactive protein. There can be anemia of chronic disease.