Title : Systemic AL Amyloidosis Presenting with Restrictive Cardiomyopathy and Nephrotic Syndrome: A Case Report
Abstract:
Background:
AL (light-chain) amyloidosis is a rare multisystem disorder caused by extracellular deposition
of monoclonal immunoglobulin light chains, leading to progressive organ dysfunction.
Cardiac involvement is the strongest predictor of mortality and often presents with
nonspecific clinical manifestations, resulting in delayed diagnosis, particularly in low- and
middle-income settings.
Case Presentation:
We report the case of a 70-year-old male referred for evaluation of chronic lower limb
edema and marked left ventricular hypertrophy identified on transthoracic
echocardiography. The patient had a long history of exertional dyspnea and episodic
wheezing previously treated as asthma with prolonged oral corticosteroid therapy. Physical examination revealed bilateral pitting edema, macroglossia, and features suggestive of
restrictive cardiomyopathy.
Laboratory investigations demonstrated nephrotic-range proteinuria (4.9 g/24 hours),
hypoalbuminemia, dyslipidemia, and elevated lambda free light chains with a markedly
reduced kappa-lambda ratio. Renal biopsy confirmed amyloid deposition involving the
glomeruli and vasculature. Echocardiography showed extreme concentric left ventricular
hypertrophy with preserved ejection fraction, consistent with infiltrative cardiomyopathy. A
diagnosis of systemic AL amyloidosis with cardiac and renal involvement was established.
The patient was initiated on supportive heart failure and nephrotic syndrome management
and subsequently commenced on chemotherapy with a VRd regimen consisting of
bortezomib, lenalidomide, and dexamethasone. However, his clinical course was
complicated by urosepsis, acute kidney injury requiring dialysis, and progression to multiple
organ dysfunction syndrome, resulting in poor clinical outcome.
Conclusion:
This case highlights the diagnostic challenges of systemic AL amyloidosis, particularly when
presenting with symptoms mimicking common cardiopulmonary disorders. Recognition of
red flag features such as unexplained left ventricular hypertrophy with preserved systolic
function, nephrotic-range proteinuria, and multisystem involvement is essential for timely
diagnosis and early initiation of therapy to improve patient outcomes.
Keywords:
AL amyloidosis; restrictive cardiomyopathy; nephrotic syndrome; infiltrative
cardiomyopathy; proteinuria
