Carpal Tunnel Syndrome and Trigger Digit: An Early Symptom of Cardial Amyloidosis

Abstract

Abstract Background Amyloidosis is a disease with misfolded protein deposits. The subform transthyretin amyloidosis (ATTR) presents with heart failure, atrial fibrillation and bundle branch block, often requiring pacing. Soft tissue deposits may occur, causing trigger digit (TD) and carpal tunnel syndrome (CTS). These may be an initial symptom of systemic amyloidosis with cardiac manifestation, they precede cardiac amyloidosis on average 5-9 years. Studies showed positivity of up to 22.5% for ATTR in tenosynovial biopsies in CTS-patients identified by a screening algorithm. ATTR is found in around 25% of autopsies at 80 years and older, with underestimated prevalence in the general population. Aims Early detection is crucial in treating systemic amyloidosis. Therefore, biopsies taken during carpal tunnel release (CTR) and trigger release (TR) can contribute significantly to its diagnosis. Methods Patients admitted in 2022 to our hospital were examined prospectively and biopsied if macroscopic intraoperative synovial hyperplasia was present. Histologic examination was done with Congo red staining and immunohistologic examination for ATTR. Patients tested positive for ATTR were offered a cardiologic follow-up. Results 118 patients (63 CTS, 55 TD) were included in the study, 40 (34%) underwent partial synovectomy. Of these, 3 patients (7.5%) were positive for ATTR. 1 patient had an unremarkable cardiologic examination, 1 patient declined, 1 patient is pending. Conclusions Early detection of amyloidosis by CTR and TR is a topic of increasing relevance. In our study, the positivity rate was lower than in others. However, there was different patient selection, e.g., according to macroscopic findings instead of a screening algorithm. The observation period is insufficient to record any cardiac results; a follow-up in 5-10 years would be appropriate. Current therapy for amyloidosis aims to delay the disease progress by preventing deposit formation, with no therapy degrading pre-existing deposits. Thus, early detection is crucial for disease outcome and justifies additional screening cost.