Tenosynovial and Cardiac Amyloidosis in Patients Undergoing Carpal Tunnel Release

BACKGROUND

Patients with cardiac amyloidosis often have carpal tunnel syndrome that precedes cardiac manifestations by several years. However, the prevalence of cardiac involvement at the time of carpal tunnel surgery has not been established.

OBJECTIVES

The authors sought to identify the prevalence and type of amyloid deposits in patients undergoing carpal tunnel surgery and evaluate for cardiac involvement. The authors also sought to determine if patients with soft tissue transthyretin (TTR) amyloid had abnormal TTR tetramer kinetic stability.

METHODS

This was a prospective, cross-sectional, multidisciplinary study of consecutive men age ≥50 years and women ≥60 years undergoing carpal tunnel release surgery. Biopsy specimens of tenosynovial tissue were obtained and stained with Congo red; those with confirmed amyloid deposits were typed with mass spectrometry and further evaluated for cardiac involvement with biomarkers, electrocardiography, echocardiography with longitudinal strain, and technetium pyrophosphate scintigraphy. Additionally, serum TTR concentration and tetramer kinetic stability were examined.

RESULTS

Of 98 patients enrolled (median age 68 years, 51% male), 10 (10.2%) had a positive biopsy for amyloid (7 ATTR, 2 light chain [AL], 1 untyped). Two patients were diagnosed with hereditary ATTR (Leu58His and Ala81Thr), 2 were found to have cardiac involvement (1 AL, 1 ATTR wild-type), and 3 were initiated on therapy. In those patients who had biopsy-diagnosed ATTR, there was no difference in plasma TTR concentration or tetramer kinetic stability.

CONCLUSIONS

In a cohort of patients undergoing carpal tunnel release surgery, Congo red staining of tenosynovial tissue detected amyloid deposits in 10.2% of patients. Concomitant cardiac evaluation identified patients with involvement of the myocardium, allowing for implementation of disease-modifying therapy. (Carpal Tunnel Syndrome and Amyloid Cardiomyopathy; NCT02792790).

[Diagnostic pitfalls in carpal tunnel syndrome]

BACKGROUND

This review focuses on the main aspects of positive and differential diagnosis of carpal tunnel syndrome (CTS) in different clinical situations encountered in daily practice.

STATE OF THE ART

Authentic CTS can be discovered in situations, which alter the usual presentation or therapeutic management. This is the case for instance in pregnant women or in the elderly subject or with acute motor forms where CTS discloses a focal intratunnel disorder (neuroma, lipoma, arterial condition, bone disorder) or a general disease (hereditary neuropathy, amylosis). In certain situations, the clinical manifestations suggest a more proximal compression of the medial nerve (round pronator, Struthers arcade, or superficial flexor) or an inflammatory condition (mononeuritis, inflammatory demyelinising neuropathy). Locoregional disease may also be involved, for instance a plexus (thoracobrachial outlet syndrome, post-radiation plexitis) or radicular condition. The clinical presentation of diffuse polyneuropathy with initial manifestations involving the upper limb (ganglioneuropathies, polyradiculoneuritis, small-fiber neuropathies) may also be misleading. Finally central conditions can sometimes be confused with CTS.

CONCLUSION

A rigorous physical examination and an electroneuromyogram are determining to avoid diagnostic pitfalls.