Case Presentation: A 53-year-old woman with a history of irritable bowel syndrome-diarrhea (IBS-D), chronic pain syndrome and years of nonspecific symptoms including chronic diarrhea and neuropathy, presented with bilateral lower extremity edema. Multiple outpatient visits and studies demonstrated nonspecific autoimmune condition with questionable monoclonal gammopathy of undetermined significance (MGUS) as well as a presumed diagnosis of fibromyalgia. Upon this presentation, exam demonstrated chronic hypotension with a systolic blood pressure of 90 mmHg, and pedal edema. Labs were significant for anemia (Hb 9.3 g/dL), AKI (Cr 2.23 mg/dL), elevated BNP (9682 pg/dL), urinalysis with 100 mg/dL protein, with protein/creatinine ratio 1086 mg/g. Infection workup including HIV and hepatitis were negative. Complete autoimmune workup was also unremarkable, aside from a low C3 complement level (63 mg/dL). Serum protein electrophoresis (SPEP) demonstrated hypogammaglobulinemia and elevations in Kappa (2.87 mg/dL) and Lambda (16.99 mg/dL) light chains, with low Kappa/Lambda ratio (0.17). The patient was started on furosemide for lower extremity edema, without much improvement. Transthoracic Echocardiogram (TTE) demonstrated severe diastolic dysfunction and thickened ventricular walls. Follow up cardiac MRI showed infiltrative cardiomyopathy, with subsequent nuclear medicine scan equivocal for transthyretin cardiac amyloidosis. Due to worsening kidney function, a renal biopsy was performed and demonstrated AL amyloidosis. Final bone marrow biopsy confirmed the diagnosis of Primary Amyloidosis, AL-type. Chemotherapy was initiated for the patient.
Discussion: This patient’s long history of diarrhea, neuropathy, hypotension, and questionable MGUS went undiagnosed for years but rather misdiagnosed as fibromyalgia, until presentation with lower extremity edema, which led to a cardiac workup demonstrating infiltrative disease. Typically, amyloidosis affects either the cardiovascular or renal system. However, this patient’s constellation of symptoms and labs demonstrated both cardiac and renal involvement, which is a rare entity with only two cases in the literature. AL amyloidosis should be considered in patients presenting with concomitant diastolic heart failure and renal failure in the setting of elevated serum immunoglobulin light chains. Chemotherapy is a standard treatment option for AL amyloidosis with hematopoietic cell transplant (HCT) as the goal if a viable option. AL amyloid has varying degrees of response to standard chemotherapy depending on the extent of disease involvement. The hematologic response is as high as 60% with response rates dropping to 17% and 25% with cardiac and renal involvement, respectively. With localized disease, median survival is typically five years, with poorer prognosis in diffuse involvement.
Conclusions: As described above, the rarity of amyloidosis, especially with both renal and cardiac involvement, should not deter clinicians from considering the diagnosis, especially in the setting of a constellation of symptoms. Although it may not always be likely, this case highlights the importance of tying together all organ systems in the hopes of identifying a unifying diagnosis.