Pass the Spinach

By Peter Galvin, MD

Today’s case is from the Hiroshima-Nishi Medical Center in Hiroshima, Japan. A 75-year-old man presented to the cardiology clinic with a three-week history of fatigue and palpitations. On physical examination, his heart rhythm was irregular. His jugular veins were distended, and he had leg edema (swelling) and bulging of the bicep muscles during elbow flexion (Panels A and B). This finding, known as the Popeye sign, indicates rupture of the distal (at the elbow) biceps tendon, had been present for four years. An EKG showed atrial fibrillation. An echocardiogram (heart sonogram) showed left ventricular hypertrophy (enlargement) and an ejection fraction (EF) of 44% (reduced cardiac output – normal EF is 60% to 65%). A biopsy of his heart muscle revealed amyloid deposits. Genetic testing identified a wild-type transthyretin gene. He was diagnosed with wild-type transthyretin amyloidosis (WTTA).

Amyloidosis is a disease that involves the production of misshapen proteins that break down in circulation, leaving deposits of abnormal proteins (amyloid fibrils) in certain body tissues and organs. There are 36 different types of amyloidosis, each caused by different types of protein misfolding (misshapen proteins). WTTA occurs because of a gene mutation that occurs spontaneously (in the “wild”). This is opposed to the inherited form called thyretin-related hereditary amyloidosis (TRHA). The thyretin gene controls the production of the protein transthyretin. In either disease, the abnormal thyretin gene causes transthyretin to be misshapen, so it breaks down in tissues where deposits of amyloid form, causing breakdown of these tissues and malfunction of the involved organs. WTTA usually occurs later in life, so it is usually seen in people aged 80 years and older, and it affects primarily tendons and the heart. TRHA usually occurs in much younger people because it is inherited and not caused by a gene mutation. The Popeye sign is commonly seen in WTTA. The biceps tendon ruptures due to weakening by amyloid deposits and the biceps muscle shortens and bunches up. Likewise, atrial fibrillation and heart failure are also common in WTTA.

There is no medication or treatment that prevents amyloid deposition. Tafamidis (Vynaqel, Vyndamax) delays disease progression but does not stop it. The patient in this case was placed on a diuretic (for the swelling), edoxaban (a blood thinner to prevent stroke from atrial fibrillation), and tafamidis. At six-month follow-up, the patient remained stable.

Please direct questions or comments to editor@rockawaytimes.com