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LETTER TO THE EDITOR |
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Year : 2014 | Volume
: 7
| Issue : 5 | Page : 686-687 |
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Role of high-resolution ultrasound in diagnosis and follow-up of leprosy patients
Amit Kharat, Dhaval K Thakkar, Mansi Jantre, Amarjit Singh
Department of Radio-Diagnosis, Dr. D. Y. Patil Medical College, Pimpri, Pune, Maharashtra, India
Date of Web Publication | 10-Sep-2014 |
Correspondence Address: Amit Kharat Department of Radio-Diagnosis, Dr. D. Y. Patil Medical College, Pimpri, Pune, Maharashtra India
Source of Support: None, Conflict of Interest: None | Check |
DOI: 10.4103/0975-2870.140501
How to cite this article: Kharat A, Thakkar DK, Jantre M, Singh A. Role of high-resolution ultrasound in diagnosis and follow-up of leprosy patients. Med J DY Patil Univ 2014;7:686-7 |
Sir,
To complement the case report histoid leprosy in Type II reaction with neural abscess: Treated with ulnar nerve decompression and anterior transposition by Patvekar et al., [1] we would like to highlight the role of high-resolution ultrasound (HRUS) in diagnosis and follow-up of leprosy patients.
Leprosy also known as Hansen's disease, a treatable condition, affects mainly the peripheral nerves. Due to loss of sensation, untreated cases of leprosy present with ulcers and deformity. We would like to highlight the role of HRUS in imaging of leprosy which mainly includes nerve enlargement and inflammation. By using HRUS and color Doppler flow study, we can easily diagnose and demonstrate these findings. Peripheral nerves can be imaged in leprosy by using a high-resolution 7-11 MHz linear ultrasound (US) transducer. HRUS assessment of thickened nerves in leprosy includes bilateral ulnar, median, lateral popliteal and posterior tibial nerves however; other nerves can also be included.
In leprosy, examination of nerves by clinical examination is subjective and inaccurate. HRUS can provide an objective measure of nerve damage by demonstrating the nerve thickening, altered echotexture and abnormal vascularity. HRUS can show changes in nerve to be more extensive and can show more nerves to be involved than clinically expected. [2] Furthermore, complications such as nerve abscess described in the case report by Patvekar et al., [1] can be accurately determined. The abscess can be quantified prior to surgical interventions. Besides, it can also be used for close follow-up and surveillance of nerve postsurgical repair, in its new transplanted position.
It has been documented that nerve enlargement is often seen in the leprosy patients with Type I or Type II reaction. These nerves of the affected patients have been shown to have increased vascularity in both the clinically involved nerves and also in nerves far distant from those clinically affected. This makes US modality of choice in mapping of thickened nerves in mononeuropathies and polyneuropathies and this has propelled a new interest in US as a diagnostic tool for similar disorders. [3],[4]
Ultrasound has numerous advantages in imaging of leprosy; it is safe and noninvasive way to assess structural changes in nerve at sites that cannot be biopsied for histopathology. It is the modality of choice in assessing the nerves as compared to magnetic resonance imaging (MRI), which is very costly. Also US can map the nerves for a longer extent when compared to the MRI. US has high intra-tissue contrast resolution when compared to MRI. Furthermore, it is rapid and can be done bedside. Based on the US imaging appearance, a thickened nerve in leprosy could be classified as [Table 1]:
Ascertaining the presence of enlarged nerves can be challenging and for some nerves this is daunting clinically because of their location, as the nerves travels deeper and lies between fascial planes. [5] Palpation is an insensitive method to assess the length of nerve abnormality. It has been found that there exists considerable inter-observer variability to study the presence of enlarged nerves by palpation. [6] In contrast, there is an excellent inter-observer agreement between US measurements of thickened nerves. [7]
Besides enlargement, nerves in leprosy patients exhibit varying degrees of structural abnormalities such as fusiform enlargement with disruption of fascicles, edema and increased nerve vascularity with or without central necrosis and abscess. [8] Nerve enlargements extend far proximal to the compression sites of the ulnar and median nerve, occasionally with a nerve length abnormality of 22 cm as found in Jain et al. study. [2] It also documented that the maximum nerve enlargement is not just proximal to the possible compression sites, but for the median nerve approximately 4 cm from the proximal carpal tunnel inlet and for the ulnar nerve 4-6 cm above the sulcus. [2] It is considered that at these sites the temperature of the nerves could be lowest and more prone to infection by Mycobacteriun leprae, which is thought to show affinity to nerve sites where lower body temperatures are noted. [9],[10]
References | | |
1. | Patvekar MA, Dev S, Rizvi A, Malhotra R. Histoid leprosy in type II reaction with neural abscess: Treated with ulnar nerve decompression and anterior transposition. Med J D Y Patil Univ 2014;7:392-5. |
2. | Jain S, Visser LH, Praveen TL, Rao PN, Surekha T, Ellanti R, et al. High-resolution sonography: A new technique to detect nerve damage in leprosy. PLoS Negl Trop Dis 2009;3:e498. |
3. | Beekman R, Visser LH. High-resolution sonography of the peripheral nervous system - A review of the literature. Eur J Neurol 2004;11:305-14. |
4. | Visser LH. High-resolution sonography of the common peroneal nerve: Detection of intraneural ganglia. Neurology 2006;67:1473-5. |
5. | Wilder-Smith EP, Van Brakel WH. Nerve damage in leprosy and its management. Nat Clin Pract Neurol 2008;4:656-63. |
6. | Chen S, Wang Q, Chu T, Zheng M. Inter-observer reliability in assessment of sensation of skin lesion and enlargement of peripheral nerves in leprosy patients. Lepr Rev 2006;77:371-6. |
7. | Beekman R, Schoemaker MC, Van Der Plas JP, Van Den Berg LH, Franssen H, Wokke JH, et al. Diagnostic value of high-resolution sonography in ulnar neuropathy at the elbow. Neurology 2004;62:767-73. |
8. | Martinoli C, Derchi LE, Bertolotto M, Gandolfo N, Bianchi S, Fiallo P, et al. US and MR imaging of peripheral nerves in leprosy. Skeletal Radiol 2000;29:142-50. |
9. | Dastur DK, Pandya SS, Antia NH. Nerves in the arm in leprosy. 2. Pathology, pathogenesis and clinical correlations. Int J Lepr Other Mycobact Dis 1970;38:30-48. |
10. | Sabin TD, Hackett ER, Brand PW. Temperatures along the course of certain nerves often affected in lepromatous leprosy. Int J Lepr Other Mycobact Dis 1974;42:38-42. |
[Table 1]
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