Synovial fluid analysis for diagnosis of amyloid arthropathy

Amyloid arthropathy in smoldering myeloma: Do not take it lightly

We report a case of smoldering multiple myeloma patient who developed signs and symptoms consistent with polyarthritis. A PET-CT demonstrated marked FDG activity in multiple joints, concerning for inflammatory arthritis. Arthrocentesis from the glenohumeral joint was consistent with inflammatory synovial fluid with no evidence for infection or crystals. Congo-red stain of the synovial fluid was positive, and mass-spectrometry based amyloid typing was consistent with wild-type transthyretin type. The patient responded instantly to glucocorticoids. This case reports highlights the feasibility of non-tissue diagnosis of amyloidosis using body fluids and underscores the importance of accurate typing to avoid erroneous treatment

Systemic Amyloidosis Caused by Monoclonal Immunoglobulins: Soft Tissue and Vascular Involvement

Clinical features of soft tissue amyloid light-chain (AL) amyloidosis include macroglossia, arthropathy, muscle pseudohypertrophy, skin plaques, and carpal tunnel syndrome. Vascular manifestations of AL amyloid include periorbital ecchymosis, jaw or limb claudication, and even myocardial infarction caused by occlusion of small vessel coronary arteries. Some of these features, such as macroglossia, periorbital ecchymosis, and the so-called shoulder-pad sign, are pathognomonic for AL amyloidosis. These findings may be the initial presenting features of the disease, and the recognition of these red flag symptoms is very important for the diagnosis and early intervention on the underlying plasma cell disease.

[A systemic disease mimicking a rheumatoid arthritis]

INTRODUCTION

Rare systemic diseases such as amyloidosis can mimic inflammatory rheumatic diseases. Because of their poor prognosis, physicians should rule them out at the onset of inflammatory rheumatism. We report a case of AL amyloidosis misdiagnosed as rheumatoid arthritis.

CASE REPORT

A 71-year-old woman was referred for seronegative rheumatoid arthritis, resistant to three biologic therapies. She had an IgA lambda monoclonal gammopathy of undetermined significance (MGUS). The patient subsequently developed glomerular proteinuria. Abdominal fat and accessory salivary glands biopsies revealed amyloid light-chain (AL) amyloidosis. Treatment with bortezomib-cyclophosphamide-dexamethasone, led to complete hematologic, renal and rheumatologic remission. Ten months after treatment interruption, the patient had an articular and hematologic relapse.

CONCLUSION

Amyloid light-chain amyloidosis arthropathy is probably underdiagnosed. A review of amyloid arthropathy associated with multiple myeloma found that 33% of patients had been misdiagnosed with rheumatoid arthritis.

Clinical Applications of Synovial Biopsy

The synovial tissue is a primary target of multiple diseases characterized by different pathogenic mechanisms, including infective, deposition, neoplastic, and chronic immune-inflammatory pathologies. Synovial biopsy can have a relevant role in differential diagnosis of specific conditions in clinical practice, although its exploitation remains relatively limited. In particular, no validated synovial-tissue-derived biomarkers are currently available in the clinic to aid in the diagnosis and management in most frequent forms of chronic inflammatory arthropathies, namely rheumatoid arthritis (RA) and the spondyloarthritides (SpA). In this brief review, we will discuss the current spectrum of clinical applications of synovial biopsy in routine rheumatologic care and will provide an analysis of the perspectives for its potential exploitation in patients with chronic inflammatory arthritides.

[Synovial fluid cytodiagnosis]

Synovial fluid samples represent only a very small percentage of routine work in a cytology laboratory. However, its microscopic examination allows us to observe different types of cells, particles and structures that, due to their morphological characteristics, may provide relevant data for cytodiagnosis. We present certain aspects related to arthrocentesis, the relationship between the gross appearance of synovial fluid and certain pathological processes, as well as the different techniques for processing and staining the smears. Furthermore, we describe the main cytological findings in various pathological conditions of the synovial joints, such as infections (bacterial and fungal), non-infectious inflammatory type (osteoarthrosis, rheumatoid arthritis, connective tissue diseases) and tumoral, distinguishing between primary and metastatic, both solid and haematological neoplasms.

Amyloid arthropathy and Waldenström macroglobulinemia

Amyloid arthropathy occurs chiefly as a manifestation of beta(2) microglobulin amyloidosis in patients receiving chronic hemodialysis. AL amyloidosis complicating multiple myeloma is a less common cause. Amyloid arthropathy is exceedingly rare in patients with Waldenström macroglobulinemia. We report a case characterized by lymphoplasmocytoid malignancy with monoclonal IgM production and amyloid arthropathy manifesting as bilateral symmetric polyarthritis. A synovial membrane biopsy established the diagnosis. Chemotherapy was effective in alleviating the joint manifestations. Joint symptoms in patients with monoclonal gammopathies, including those characterized by IgM secretion, should suggest amyloid arthropathy. Treatment of the blood disease may improve the joint symptoms.

Charcot knee arthropathy with articular amyloid deposition in familial amyloidotic polyneuropathy

An extremely rare case of familial amyloidotic polyneuropathy (FAP) complicated by neuroarthropathy (Charcot joint) in the left knee joint and by intra-articular deposits of amyloid was observed. FAP-specific variant transthyretin (TTR) was found in the synovial fluid and amyloid deposits were confirmed in the synovium, cartilage and bone by Congo red staining and immuno-staining.

Clinical and therapeutic aspects of AA amyloidosis

Approach to the management of AA amyloidosis complicating RA. (A) In case of proteinuria or loss of renal function a rectal biopsy or a subcutaneous fat biopsy is a suitable screening method for the detection of amyloidosis. If in any doubt, try to ascertain the diagnosis by renal biopsy. Adequate staining with alkaline Congo red and preferably immunohistochemical staining with anti-AA antibodies should be performed. Beware of renal pathology other than amyloidosis even in the presence of a positive rectal biopsy. (B) A vigorous attempt to control disease activity of the RA should be made in order to eliminate the production of SAA, an acute phase protein. The response to treatment should be monitored by serial measurements of CRP and preferably SAA. (C) The function of some vital organs should be evaluated: (a) endogenous creatinine clearance and the extent of proteinuria; (b) electrocardiogram and optional echocardiography; (c) thyroid function and adrenocortical function; (d) intestinal absorption tests; (e) optional--SAP scintigraphy and turnover studies. (D) Attention should be given to adequate supportive treatment: (a) blood pressure control; (b) treatment of intercurrent infections; (c) corticosteroids during major surgical procedures; (d) pay attention to the possible effect of NSAID on proteinuria and renal function. (E) In case of total renal failure or uncontrollable proteinuria: (a) consider the possibility of primary renal transplantation; (b) otherwise regular haemodialysis is indicated.

Primary systemic amyloidosis--a diagnostic primer

Primary systemic amyloidosis (immunoglobulin light chain-derived) (AL) is an uncommon dysproteinemia with highly varied initial clinical manifestations. Among 153 patients with this disorder, the median survival was 20.4 months (5-year survival, 19.6%). The worst outcome was associated with overt congestive heart failure (median survival, 7.7 months; 5-year survival, 2.4%). The patients with the best outcome were those who had amyloid neuropathy without associated cardiac or renal involvement (median survival, 39.7 months; 5-year survival, 31.6%). Serum protein electrophoresis and immunoelectrophoresis are the most important tests because a monoclonal protein can be detected in almost two-thirds of the patients. When screening of both serum and urine is performed, a monoclonal protein is found in 86% of patients. Such screening is helpful if primary systemic amyloidosis is to be detected and treated early.