Atypical Presentation of Systemic Amyloid Light Chain (AL) Amyloidosis.

Light chain (AL) amyloidosis is caused by a plasma cell clone that produces a dysfunctional, monoclonal light chain. This light chain misfolds and aggregates, resulting in catastrophic organ damage and eventual death. Due to the multiple organs affected by the disease, symptoms can be vague, such as lethargy, fatigue, weight loss, and peripheral edema. This case presentation follows a 66-year-old female patient who presented to our emergency department complaining of progressive shortness of breath (SOB). The patient denied any other associated symptoms and denied any past significant medical history. The lack of other associated symptoms or past diagnoses was a part of this atypical presentation, as the patient frequently complained of a multitude of symptoms affecting more than one organ system, as the pathogenesis of the disease is systemic in nature. Additionally, individuals with undiagnosed amyloidosis have often been diagnosed with other disease processes based on their symptomatology, due to their sometimes nonspecific nature. Upon further evaluation, bilateral pleural effusions were noted on imaging, which was treated with a pigtail pleural catheter. Atrial fibrillation was noted on ECG and was treated with both rate- and rhythm-controlled amiodarone. AL amyloidosis was suspected on transthoracic cardiac ultrasound, which was described as a "grainy" appearance of the myocardium, along with heart failure and left ventricular hypertrophy, supported by serum protein electrophoresis (SPEP) and urine protein electrophoresis (UPEP) results. This was confirmed by abdominal fat pad and bone marrow biopsies. While the use of cardiac ultrasound in the preliminary workup of amyloidosis is supported by evidence-based practice, there is a need for confirmatory diagnostic testing. This led to the decision to utilize fat pad biopsy as the primary definitive diagnostic tool, as it was readily available within the hospital system and was technically easier than many of the alternatives. However, this is neither supported nor refuted as the gold standard by the available literature. The patient was transferred to a higher level of care at a center specifically focused on the treatment of amyloidosis to receive the current gold standard of treatment, which was unavailable at our facility due to a lack of these specialized medications, as well as a provider comfortable with the use of these treatments.