Key Information
We present a case of a 51-year-old woman diagnosed with light chain amyloidosis associated with monoclonal gammopathy of undetermined significance (MGUS). Initially, she presented with symptoms of heart failure, including palpitations, chest tightness, and shortness of breath, which were attributed to myocarditis based on cardiac magnetic resonance (CMR) imaging findings. However, her condition rapidly deteriorated, with recurrent admissions for worsening heart failure, cardiogenic shock, and stroke. A cardiac biopsy ultimately confirmed light chain amyloidosis, a rare complication of MGUS, which has a long-term risk of 0.8% in patients with light chain MGUS. Despite aggressive treatment, including chemotherapy and biventricular assist device implantation, her condition continued to decline, and she became ventilator-dependent and subsequently passed away. This case highlights the importance of considering amyloidosis in patients with MGUS and underscores the need for early diagnosis and intervention to prevent catastrophic outcomes.
Keywords: amyloidosis, biventricular assist device, cardiac mri, heart failure, left ventricle, left ventricular systolic function, light chain mgus, monoclonal gammopathy of undetermined significance, multi-disciplinary teams
Introduction
In the United Kingdom, over 0.8 persons per 100,000 are thought to be affected by amyloidosis [1external link, opens in a new tab]. About 500-600 new cases are diagnosed each year, and it is the cause of death between 0.5 and one out of every 1000 people [2external link, opens in a new tab]. Amyloidoses are a class of protein-folding disorders characterised by the infiltration of one or more organs by proteinaceous deposits known as amyloid [3external link, opens in a new tab]. The deposits are derived from one of several amyloidogenic precursor proteins; the organ(s) involved and the type of amyloid will determine the prognosis of the disease [3external link, opens in a new tab]. Cardiac amyloidosis carries the worst prognosis of any involved organ, and light chain (AL) amyloidosis is the most serious form of the disease [3external link, opens in a new tab]. The importance of early diagnosis of AL cardiac amyloidosis cannot be overemphasised. If untreated, the median survival from the onset of heart failure is approximately six months [3external link, opens in a new tab].
Monoclonal gammopathy of undetermined significance (MGUS) affects 3.2% of adults aged >50 years [4external link, opens in a new tab], with light chain MGUS accounting for 1% of all cases in the <50 age group [5external link, opens in a new tab]. The long-term risk of developing amyloidosis in patients with MGUS is estimated to be 0.8%.