Case Series
The Role of High-resolution Nerve Ultrasonography in Atypical Presentations
of Hansen’s Disease: A Case Series
TR01-TR04
Correspondence
Dr. Madhavi KanDr. Madhavi Kandagaddala,
Professor, Department of Radiology, CMC Vellore-632004, Tamil Nadu, India.
E-mail: madhoo116@gmail.comdagaddala,
Professor, Department of Radiology, CMC Vellore-632004, Tamil Nadu, India.
E-mail: madhoo116@gmail.com
Hansen disease is a chronic infectious disease with a predilection for peripheral nerves. Clinical examination may underestimate the extent of nerve involvement, particularly in patients with suspected mononeuropathy or atypical presentations. This case series describes five cases of Hansen disease in which high-frequency ultrasonography contributed to diagnosis and disease mapping. Patients were referred for ultrasound evaluation either with suspected involvement of a single peripheral nerve or with an alternative clinical diagnosis. High-Resolution Ultrasound (HRUS) was performed using a Philips EPIQ machine with an 18 MHz linear transducer, assessing the symptomatic nerve and additional accessible peripheral nerves bilaterally. Sonographic features including nerve thickening, altered fascicular pattern, hypoechogenicity, focal or diffuse enlargement were recorded. Assessment of the nerves was done on long and short axis imaging of each nerve and single measurements of Cross-sectional Area (CSA) were taken at the point of maximum nerve thickening by a single observer. Ultrasound revealed additional clinically unsuspected nerve thickening in three cases and redirected clinical suspicion toward Hansen disease in two cases initially thought to have other pathology. This series highlights high-frequency ultrasonography as a useful, non-invasive adjunct for mapping peripheral nerve involvement in Hansen disease and for raising diagnostic suspicion in atypical or clinically underestimated presentation. Although the World Health Organisation (WHO) has prescribed three diagnostic cardinal signs which include definitive loss of sensation in a pale or reddish skin patch, thickened or enlarged peripheral nerves with associated sensory or motor loss, and microscopic identification of Acid-Fast Bacilli (AFB) in a slit-skin smear, in tertiary and specialised medical settings, the absolute confirmation of Hansen’s Disease (HD) relies on histopathological examination of a skin biopsy. A significant advantage of HRUS is its non-invasive nature. It is also useful in cases of Pure Neural Leprosy (PNL) where patients do not have skin lesions and negative skin smears, HRUS allows for diagnosis by documenting absolute nerve asymmetry and thickening especially in cases where an invasive nerve biopsy could cause permanent nerve damage. HRUS is also useful to identify early subclinical structural nerve abnormalities, asymmetrical cross-sectional enlargement, and internal fascicular changes before nerve damage translates into sensory or motor loss which can be identified during a routine clinical exam. Ultrasound also helps visualise the exact location of nerve thickening and can differentiate it from other aetiologies such as entrapment neuropathy.