Nephrotic Range Proteinuria and Restrictive Heart Failure in a Patient with Secondary Amyloidosis: A Case Report

Amyloidosis is a rare condition in which a protein called amyloid accumulates in organs. The amyloid accumulation can impair organ function. The heart, kidneys, liver, spleen, neurological system, and digestive tract might all be impacted.

Certain types of amyloidosis coexist with other disorders. These types of illnesses may improve with therapy for other conditions. Some kinds of amyloidosis can result in life-threatening organ failure.

Chemotherapy with potent cancer-fighting medicines is one option for treatment. Other drugs can help lower amyloid production and alleviate symptoms. Some individuals may benefit from organ or stem cell transplants [1].

Nephrotic syndrome (NS) is characterized by high proteinuria (more than 40 mg/m^2 per hour) and hypoalbuminemia (less than 30 g/L), leading to hyperlipidemia, edema, and other problems. It is produced by increased permeability of the damaged basement membrane of the renal glomerulus. It is caused by an anomaly in glomerular permeability, which can be primary with a kidney-specific illness or secondary to congenital infections, diabetes, systemic lupus erythematosus, neoplasia, or particular medication usage [2].

The current study diagnoses Amyloidosis as a result of persistent inflammation caused by a past tuberculosis infection, which is accompanied by nephrotic proteinuria and restrictive cardiomyopathy.

Amyloidosis is a broad category of disorders distinguished by the buildup of insoluble, misfolded proteins in tissues. These proteins can accumulate locally, as seen in Alzheimer's disease, or systemically. The disease's clinical signs are generated by the harmful consequences of aggregated proteins accumulated in tissues. The typical age of diagnosis is in the seventh decade of life, and almost any organ can be damaged. The most common organs affected are the heart, peripheral nerves, kidneys, liver, and gastrointestinal tract, although cardiac, renal, or autonomic nervous system malfunction is commonly the cause of death. The disease's natural history is almost invariably progressive, but it can occasionally be reversed as aggregated protein is turned over [5].

A clinical appearance suggestive of an amyloidosis syndrome and tissue confirmation of Congo red-positive extracellular deposits exhibiting apple green birefringence under polarized light microscopy are necessary for the diagnosis of systemic amyloidosis. The easiest tissue to access for diagnosis has been fat aspiration, yet its yield varies depending on the kind of amyloid, from 15% to 80%. The pathologic examiner's abilities and the amount of fat extracted both affect how sensitive fat aspiration is. Histologically, all kinds of amyloidosis have identical amyloid deposits. As a result, amyloid typing, or the identification of the precursor protein, is a critical step in the diagnostic assessment and has consequences for prognosis, therapy, and diagnosis when performed on tissue samples containing amyloid [6]. In medical practice, amyloid is now classified according to the kind of amyloid protein. The amyloid is referred to as A (for amyloid), followed by an acronym of the protein type: AL (amyloid derived from immunoglobulin light chain), AA (amyloid A/secondary amyloidosis) and ATTR (amyloid derived from transthyretin), etc. [7]. The sensitivity and specificity of typing techniques vary. The most trustworthy technique is mass spectrometry (MS) proteomic-based analysis, which finds the universal amyloid proteins (apolipoprotein A-IV, serum amyloid P, and apolipoprotein E) along with the protein component in the deposit directly. Because MS has a sensitivity and specificity of about 100% and can identify rare or novel types, it is the gold standard for typing [6] AA amyloidosis can be associated with any type of chronic inflammation (e.g., rheumatoid arthritis, inflammatory bowel disease, subacute bacterial endocarditis, tuberculosis).

The kidneys are the first organs to be implicated in AA amyloidosis, followed by hepatomegaly, splenomegaly, and autonomic neuropathy. Excess protein in the urine, or proteinuria, is a common indicator of renal involvement. Usually severe, this illness results in the nephrotic syndrome. Less frequently, the first indication of renal disease brought on by amyloid is growing azotemia, or an excess of urea and other nitrogenous wastes in the blood. Without heart failure, nephrotic syndrome is characterized by an abnormal accumulation of fluid, such as edema in the legs and abdomen. It also involves hypercholesterolemia, or an excess of cholesterol in the blood, which may be quite serious [8]. Cardiomyopathy develops in the latter stages of the disease. Several years of an underlying inflammatory condition with chronic elevated SAA levels usually precede fibril development, while infections might cause AA deposition more quickly.

Signs and symptoms of amyloidosis include fatigue or weakness, weight loss, shortness of breath, swollen feet or legs, and eye bruises, among others [9].

The primary treatment for AA amyloidosis is to treat the underlying inflammatory or infectious condition, as well as to administer medications that decrease the inflammatory state and reduce SAA concentration and amyloid fibril deposition rate. Suppressing serum amyloid A levels to a normal range is the aim of therapy for any kind of treatment. C-reactive protein is a suitable substitute for serum amyloid A testing in cases where it is not available to evaluate the efficacy of treatment [5]. For patients with Familial Mediterranean Fever, colchicine is incredibly helpful in preventing AA amyloidosis. Colchicine can stabilize or reverse non-nephrotic renal disease in people with nephropathy at the time of colchicine initiation; however, it cannot be used in patients with nephrotic syndrome and/or uraemia. It can be used, at larger doses, to prevent disease recurrence following kidney transplantation. As a second-line treatment for Familial Mediterranean Fever and other periodic fever syndromes that are resistant to colchicine, IL-1 blocking with canakinumab, a monoclonal antibody that targets interleukin-1 beta, or anakinra, a recombinant IL-1 receptor antagonist, is advised. Anakinra has been demonstrated to be safe and efficacious for patients with AA amyloidosis of unknown cause.(6)Also, ''Eprodisate,'' a drug that inhibits serum amyloid metabolism, have all been tested and failed. There is no satisfactory treatment for amyloidosis, which is a fatal diagnosis.

Follow up: The patient was started on supportive therapy and AKT to help reduce her symptoms. The patient's relatives were informed of the poor prognosis and outcome of the treatment. The patient's follow-up indicated no more clinically significant problems.

Because amyloidosis is a rare disorder with nonspecific signs and symptoms, doctors often overlook it, leading in underdiagnosis [10]. Furthermore, chronic inflammation caused by underlying illnesses such as TB promotes the deposition of amyloid proteins in the heart and kidneys, leading in restrictive cardiomyopathy and proteinuria, among other symptoms. This study raises medical awareness of the challenges of properly detecting and treating Tuberculosis in India, highlighting the significance of continued medical education and the construction of referral institutions equipped with diagnostic technology and specific medicines. Overall, these measurements may improve patient care, with the objective of attaining improved long-term outcomes such as reduced organ failure and mortality [10].