What is most common cause of death in amyloidosis?
**Core Concept**
Amyloidosis is a group of diseases characterized by the deposition of amyloid fibrils in various tissues, leading to organ dysfunction. The most common cause of death in amyloidosis is related to cardiac involvement, which can lead to restrictive cardiomyopathy and heart failure.
**Why the Correct Answer is Right**
The correct answer is related to the pathophysiology of amyloidosis, where the deposition of amyloid fibrils in the heart leads to stiffening of the cardiac walls, impairing the heart's ability to relax and fill during diastole. This results in restrictive cardiomyopathy, which can ultimately lead to heart failure. The amyloid fibrils deposit in the interstitial tissue of the heart, including the myocardium and the conduction system, leading to electrical conduction abnormalities and arrhythmias.
**Why Each Wrong Option is Incorrect**
**Option A:** Pulmonary embolism is a potential complication of amyloidosis, but it is not the most common cause of death. Amyloid deposition in the lungs can lead to pulmonary hypertension and fibrosis, but these conditions are less common than cardiac involvement.
**Option B:** Renal failure is a common complication of amyloidosis, but it is not the most common cause of death. Amyloid deposition in the kidneys can lead to nephrotic syndrome and renal failure, but these conditions can often be managed with dialysis and transplantation.
**Option C:** Infection is a potential complication of amyloidosis, particularly in patients with AL amyloidosis and bone marrow involvement. However, infection is not the most common cause of death in amyloidosis.
**Clinical Pearl / High-Yield Fact**
It is essential to remember that the presence of cardiac involvement in amyloidosis is a poor prognostic sign, and patients with cardiac amyloidosis have a significantly worse outcome than those without cardiac involvement.
**Correct Answer: C. Cardiac involvement leading to heart failure is the most common cause of death in amyloidosis.**