Amyloidosis

Amyloidosis occurs when a normally soluble precursor protein misfolds into insoluble beta-pleated-sheet fibrils. The fibrils accumulate outside cells and behave like protein cement: they stiffen tissue, narrow functional space, and progressively impair the organs involved. Amyloidosis is therefore a systemic protein-deposition disease, not a single cardiac, renal, or neurologic disorder. The treatment decision begins with identifying the precursor. AL arises from a clonal plasma-cell disorder and requires rapid clone-directed treatment. AA reflects persistent serum amyloid A production during chronic infection or inflammation, so controlling that driver is the disease-modifying treatment. ATTR results from transthyretin and may be wild-type or hereditary. Cardiac ATTR is often suspected when heart failure with preserved ejection fraction, increased ventricular wall thickness, and conduction or rhythm disease occur in an older adult. The same patient may also disclose years of bilateral carpal tunnel syndrome or lumbar spinal stenosis. For a nurse practitioner, the high-stakes sequence is consistent: recognize the phenotype, exclude or identify a monoclonal protein, obtain tissue when required, type the deposit, and protect the restrictive heart from both congestion and underfilling while specialist treatment...