Multifocal, hypoechogenic nerve thickening in Cerebrotendinous Xanthomatosis

Abstract

Objective: To characterize peripheral nerve morphology in cerebrotendinous xanthomatosis (CTX) patients using high-resolution ultrasound (HRUS) in vivo. We hypothesized that nerve enlargements might be present in CTX as a result of accumulation of abnormal lipids with deposition also in peripheral nerves.

Methods: Four CTX patients were examined using HRUS to assess morphological abnormalities of peripheral nerves as well as cervical nerve roots 5 and 6.

Results: HRUS revealed mild to moderate, hypoechogenic thickening of sensorimotor nerves (ulnar nerve in 1/4, tibial nerve in 3/4, median nerve 4/4 patients) as well as mild enlargement of pure sensory nerves (sural nerve in 2/3, superficial FN in 2/4 patients). The vagal nerve was moderately enlarged in one patient, cervical roots showed moderate enlargements of C5 in two patients, one of which also showing thickening of C6 as well as in another patient. UPSS score was slightly to moderately abnormal in all patients. The Homogeneity score was not increased suggesting regional to inhomogeneous nerve enlargement.

Conclusions: HRUS shows multifocal, hypoechogenic nerve thickening of peripheral nerves and nerve roots in CTX.

Significance: HRUS might serve as a valuable, additive and non-invasive bedside tool to assess peripheral nerve morphology in future clinical studies on CTX patients.

Keywords: CTX; Cerebrotendinous xanthomatosis; High-resolution ultrasound; Nerve ultrasound; UPSS; Ultrasound pattern sum score.