Transthyretin-Related Cardiac Amyloidosis: A Case of Delayed Diagnosis in the Comorbid Patient and Literature Review

We report the case of an 82-year-old male with a history of bronchiectasis, asthma, and atrial fibrillation, who presented with progressive exertional dyspnoea, peripheral oedema, and recurrent heart failure exacerbations. Initial management targeted presumed pulmonary decompensation. Elevated natriuretic peptides, echocardiographic evidence of concentric left ventricular hypertrophy with preserved ejection fraction, and progressive conduction abnormalities prompted further evaluation. A 99mTc-DPD scintigraphy scan revealed Perugini grade 3 myocardial uptake consistent with wild-type transthyretin (ATTRwt) cardiac amyloidosis. Serum and urine studies excluded light-chain amyloidosis. Despite the presence of classical 'red flag' features, including atrial fibrillation, carpal tunnel syndrome, and unexplained left ventricular hypertrophy, diagnosis was significantly delayed by approximately 18 months, from initial symptom onset to definitive diagnosis, during which recurrent hospitalisations and progressive functional decline occurred. Earlier features were overlooked due to the attribution of symptoms to coexistent pulmonary disease and chronic kidney dysfunction. This case highlights the diagnostic challenges posed by ATTRwt, particularly in multimorbid older adults. Overlapping features with respiratory and renal pathology, as well as age-associated cardiovascular changes, obscure the clinical picture. Awareness of hallmark extracardiac features, systematic use of cardiac imaging, and prompt nuclear scintigraphy are essential for timely diagnosis. Early identification may enable consideration of disease-modifying therapy and improved symptom management.