Occult Cardiac Amyloidosis: The Last Chapter Of A 5- Year Long Story

Amyloidosis is a disease characterized by deposition of amyloid protein in tissues throughout the body. Of the more than 20 forms identified, the three most common types are amyloid light chain (AL), amyloid associated (AA), and amyloid beta (Ab). The prognosis depends on where in the body amyloid deposition occurs, the amount of deposition, and the symptoms. Cardiac involvement is commonly associated with the AL amyloidosis, characterized by diastolic cardiac failure and conduction system abnormalities. The most common presentation is a restrictive cardiomyopathy secondary to myocardial infiltration of amyloid protein that results primarily in diastolic dysfunction; in this group, sudden death can occur. Autopsy studies have demonstrated the rate of undiagnosed amyloidosis at death to be approximately 1–4% [1 - 2]. A case of a 53-year-old man’s death due to unsuspected, undiagnosed primary amyloidosis, predominantly involving the myocardium, is reported. In 2014 the man complained gastroenterolgical symptoms with severe weight loss. In March 2015 an electrocardiogram (ECG) showed signs of sub-epicardic ischemia; gastroenterologic study showed chronic colonic inflammation, gastritis, and reflux esophagitis. In August 2015 he was admitted to hospital with the diagnosis of colitis and chronic obstructive pulmonary disease. In September 2015 episodes of angina pectoris occurred, with signs of biventricular hypertrophy and diastolic disfunction at ECG and echocardiogram; coronography showed an intramural left anterior descending coronary artery. At the discharge, diagnosis of angina abdominis was formulated. In March 2016 a brain stroke with left hemiparesis occurred; ECG showed low peripheral voltages with increase of troponin; echocardiography showed bi-ventricular hypertrophy with peridardic effusion. Monoclonal gammopathy was also found. In July 2016 a bicameral implantable cardioverter-defibrillator was implanted because of a progressive cardiac failure, but a cardiogenic shock occurred leading to death. Post-mortem histologic examination demonstrated amorphous eosinophilic extracellular material suggestive of amyloid in lymphnodes, lungs, liver, spleen, kidneys, adrenal glands, stomach, and heart. This material stained positive with Congo red; “applegreen” birefringence was observed under polarized light. Massive subendocardial deposition of amyloid as well as in the walls of intramural arterial branches of the heart associated with myocyte degeneration, were found in the myocardium. The cause of death was progressive heart failure secondary to amyloid protein infiltration of the heart, due to underlying primary systemic amyloidosis. This case illustrates that amyloidosis should be considered within the differential diagnoses, and actively investigated in patients with unspecific and long-lasting symptoms.