Amyloidosis

AL Amyloidosis: Unfolding a Complex Disease

“…Usually, the isotype of the light chain produced is the λ light chain occurring in approximately 80% of cases ( Merlini, 2017 ). However, AL amyloidosis is not solely limited to the unnatural production of light chains and can sometimes, albeit infrequently, involve an overproduction of heavy chains or fragments ( Gertz & Zeldenrust, 2014 ). The light chain isotype may affect certain tissues more than others due to the variability in light chain sequencing, which may result in structural and biophysical differences.…”

“…Patients with extensive plasma cell infiltration of greater than 30% do not usually present with typical myeloma symptoms (hypercalcemia, renal dysfunction, anemia, lytic lesions), but rather present with symptoms of organ damage, such as cardiac symptoms, nephrotic range proteinuria, dysphagia, peripheral neuropathy, fatigue, or GI symptoms ( Kastritis & Dimopoulos, 2015 ). Patients who do not have an initial concurrent diagnosis of MM will have a less than 1% likelihood of progressing to overt myeloma ( Gertz & Zeldenrust, 2014 ).…”

“…However, the incidence of these symptoms is quite low ( Picken & Barton, 2015 ). Periorbital purpura occurs in approximately 15% of patients and appears as bruising around the eyes ( Gertz & Zeldenrust, 2014 ). Macroglossia occurs even less commonly, in fewer than 10% of patients with amyloid.…”

“…Other soft tissue findings include the “shoulder pad sign,” arthropathy, claudication, skin thickening, dry mouth, and carpal tunnel syndrome ( Kastritis & Dimopoulos, 2015 ). The “shoulder pad sign” is a rarely observed symptom and is caused by amyloid infiltration into the skeletal muscle, producing pseudohypertrophy ( Gertz & Zeldenrust, 2014 ). Notably, these symptoms may resemble a variety of rheumatologic conditions.…”

“…Thus, it is imperative for the clinician to consider the different amyloid syndromes that can occur. These include heart failure, nephrotic range proteinuria, hepatomegaly, peripheral neuropathy, and atypical multiple myeloma ( Gertz & Zeldenrust, 2014 ). At diagnosis, 46% of patients may experience 3 or more organ involvement ( Bayliss, McCausland, Guthrie, & White, 2017 ).…”