B2 Microglobulin and Bence Jones Proteinuria Guide the Diagnosis of Idiopathic AA Amyloidosis: A Journal to Diagnosis

Abstract

Amyloidosis is a disease caused by the extracellular deposition of pathological insoluble fibrillary protein in multiple tissues and may result in severe organ dysfunction. There are two major forms of amyloidosis: AL amyloid and AA amyloidosis, which complicates any chronic inflammatory condition, including rheumatologic, chronic infections, and certain neoplasms. In small but increasing numbers, the chronic inflammatory state underlying AA amyloidosis remains obscure, despite extensive investigations, which are known as idiopathic. In the current case, the first extensive evaluation to determine the inflammatory disease was negative. The patient had B2 microglobulin elevation and Bence jones proteinuria, which are non-specific findings, but are not conclusive, for malignancies. The diagnosis of Idiopathic AA amyloidosis was guided by understanding the pathophysiology of B2 microglobulin and Bence jones proteinuria along with excluding all other etiologies. Unfortunately, the development of restrictive cardiomyopathy and ESRD within 3 months indicates a rapid progression and poor prognosis in this patient. Clinicians may not be familiar that B2 microglobulin and Bence jones proteinuria are also found in amyloidosis, which may delay the diagnosis. Inflammatory process and kidney injury due to AA amyloidosis caused previous markers positivity in our patient. It is plausible that delays in diagnosis may be multi-faceted and heavily influenced by the average age of the patient, the complexity and the rareness of the disease. Also, non-disease-specific symptoms may reduce the likelihood of a prompt diagnosis. Therefore, establishing the diagnosis is difficult, and early diagnosis requires high clinical suspicion.