ABSTRACT
Leprosy is a major infectious cause of serious deformities which affects skin, nerves, eyes and limbs. In this study we have attempted to incorporate ultrasonography as an objective tool for the detection of early nerve thickening compared to healthy controls.A case control study was performed with 35 patients with leprosy as cases and 30 healthy controls. Clinical evaluation of bilateral ulnar, median and common peroneal nerves respectivelywas performed by two observers and they reached a consensus whether the nerve was thickened or not.Ultrasonography of these nerves was conducted and dimensions like cross sectional area and circumference was noted and compared with those of healthy subjects. Receiveroperator characteristics and area under curve method was used to determine cut off values for nerve thickness of each nerve. All six examined nerves showed significant thickening in leprosy patients compared to controls. Nerve involvement was more common among males at 72.4%. Around 62.8% patients belonged to the Borderline spectrum followed by lepromatous, pure neural and tuberculoid at 17.1%, 11.4% and 5.7% respectively. One patient had histoid type of lepromatous leprosy with nodular lesions. Patients with leprosy had significantly higher number of thickened nerves with p value <0.001. Asymmetric nerve thickness was noted in 54.6%. Among 210 nerve points examined 86 were found to be clinically thickened and 138 were found to be thickened ultrasonographically (p<0.001). The most common sonographic finding was focal thickening (83.3%) followed by hypoechoicity (63%). Using receiveroperator characteristics, nerve cross sectional area above 0.08cm sq. was found to be a predictor of nerve thickness.Ultrasound is a noninvasive modality that acts as an effective and objective marker of nerve thickening in leprosy. Besides detection of nerve thickening in leprosy, it can be used to identify structural changes in the nerve such as focal thickening and inflammation.