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

Case Report

Austin J Clin Immunol. 2021; 7(1):1044.

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

Alsultan M1*, Bakr A2, Hassan Q3 and Alshaar D4

1Department of Nephrology, Al Assad and Al Mouwasat University Hospital, Syria

2Department of Oncology, Al Biruni University Hospital, Syria

3Professor and Chief of Nephrology Department, Al Assad University Hospital, Syria

4Department of Histopathology, Al Assad University Hospital, Syria

*Corresponding author: Alsultan Mohammad, Department of Nephrology, Al Assad and Al Mouwasat University hospitals, Omar Ibn Abdulaziz Street, Syria

Received: October 04, 2021; Accepted: October 30, 2021; Published: November 06, 2021

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.

Keywords: AA amyloidosis; B2 microglobulin; Bence jones proteinuria

Introduction

Amyloidosis is a disease caused by the extracellular deposition of pathological insoluble fibrillary protein in multiple tissues and may result in severe organ dysfunction. Despite the etiological heterogeneity of systemic amyloidosis, the clinical manifestations of the different forms of amyloidosis largely overlap and depend upon the affected organ. Signs and symptoms that should raise suspicion for the potential diagnosis of amyloidosis are usually nonspecific; therefore, establishing the diagnosis is difficult, and early diagnosis requires high clinical suspicion [1].

There are several major forms of amyloidosis: AL amyloid is due to the deposition of protein derived from immunoglobulin light chain fragments. AA amyloidosis is a potential complication of chronic diseases in which there is ongoing or recurring inflammation. Other major forms of amyloid seen clinically include dialysis-related amyloidosis, heritable amyloidosis, age-related systemic amyloidosis and organ-specific [2].

Case Presentation

A 57-year old patient was admitted to the Nephrology Department of Al Assad University Hospital due to edema, malaise and weight loss for 3 months. His story began ten years earlier complaining of arthritis in both knees with frequent use of Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) and developed to generalized arthralgia later. Also, he had several tests, which showed anemia and elevated inflammatory markers. The patient was studied in the hematologic department before 3 months.

In the Hematologic Department, laboratory tests showed in (Table 1). Serum Protein Electrophoresis (SPEP) showed low albumin with slightly elevated alpha 1, alpha 2, beta, and gamma. Echocardiography and bone marrow biopsy were normal. Peripheral blood smear showed normochromic normocytic anemia. CT scan of the whole body along with upper and lower gastrointestinal endoscopy with biopsies were done and no tumors were found. A rheumatologic consult was requested for bone Densitometry (DEXA) and ophthalmic examination. DEXA showed generalized osteoporosis and ophthalmic examination was normal. During admission, the patient developed septic arthritis and was treated with antibiotics. The patient was discharged on low dose prednisone with calcium supplementation and referred to obtain kidney biopsy later.