Peripheral nerve ultrasound in Hansen's disease
by Glauber Voltan
Ultrasonography (USG) can be used as a complementary diagnostic method in Hansen's disease (HD) to identify neuropathy. HD is the only condition in which assessment of neural hypertrophy is central to its diagnosis,1 and is proposed by the World Health Organization as one of the three criteria for case definition of the disease.2 Simplified neurological physical examination, including palpation of the peripheral nerves, aids in the diagnosis of neural thickening and neuritis but is subjective even for well-trained professionals.3 HD is a neural disease and may or may not have cutaneous manifestations.4–10 Cases of peripheral neuropathy accompanied by neural thickening, with or without cutaneous manifestations, should lead the clinician to suspect the diagnosis of HD.11
High Resolution USG
Anatomical aspects of peripheral nerves
Figure 1: Images of peripheral nerves from healthy people, honeycomb pattern (1-A: right common fibular nerve, cross-section at fibular head and proximal; 1-B: right ulnar nerve, cross-section at cubital tunnel and proximal; 1-C schematic representation of normal peripheral nerve; 1-D left ulnar nerve, longitudinal section).
Morphological aspects of Hansen's disease neuropathy seen by high-resolution USG
Figure 2: Sonographic images and representative schemes of peripheral nerves in patients diagnosed with HD (2-A thickening of the epineurium seen by HRUS: upper = ulnar nerve, cross-section, cubital tunnel / lower = ulnar nerve, cross-section, cubital post-tunnel; 2-B several nerves with altered morphological pattern - loss of fascicular pattern; 2-C neural hypertrophy and loss of fascicular pattern of common tibial and fibular nerves in the distal third of the thigh; 2-D positive Doppler signal, endoneural or neuritis of the tibia in the left medial malleolus).
Figure 3: Ultrasound images of bilateral peripheral nerves at major neural points of the same patient diagnosed with HD showing thickening and morphological change corresponding to ulnar neuropathy hypertrophic (CSA > normal), asymmetric (∆CSA > normal), and focal (∆TPT > normal) types.