From periphery to center, untold story of pure neuritic leprosy: an electrophysiological study.

BACKGROUND: Pure neuritic leprosy (PNL) is uncommon form of leprosy involving peripheral nerves. Some isolated case reports have shown imaging changes in the central nervous system (CNS) and also impairment in visual evoked potential (VEP), somatosensory evoked potential (SSEP) and brain stem auditory-evoked potentials (BAEPs) parameters in PNL, but there is lack of large study. This prospective observational study evaluates impairment in these central conduction studies among PNL patients. METHODS: We screened patients with leprosy presenting with features of neuropathy and/or thickened nerves. Patients with bacilli-positive nerve biopsies were included in the study and subjected to routine tests along with nerve conduction study (NCS), VEP, tibial SSEP and BAEPs. Parameters of these studies were analyzed based on data from previous studies. RESULTS: Of 76 patients screened for PNL 49 had positive findings in biopsy. Most of patients were male and mean age group was 46.35 ± 15.35 years. Mononeuritis multiplex was most common NCS pattern in 46.93% (23/49) patients. We found abnormal VEP in 13 out of 35 patients (37.14%). Similarly abnormal SSEP and BAEPs among 42.85% and 40% patients respectively. DISCUSSION: This study shows that in PNL significant number of patients have subclinical CNS involvement. Exact pathophysiology of CNS involvement is not known till now but study of VEP, SSEP and BAEPs parameter may help in early diagnosis of PNL.

Multidetector computed tomography evaluation of normal thymus and variations with age.

Background: Thymus is a T-cell-producing lymphoid organ that appears prominent in the paediatric population and involutes in size with ageing. The gland shows a wide variety of appearances across different age groups. The purpose of the study is to evaluate the computed tomography (CT) appearance of thymus gland in the normal population with a focus on size, CT attenuation and fatty infiltration in different age groups. Patients and Methods: This is a retrospective study done after taking approval from the Institutional Ethics Committee. Patients undergone CT scans of the thorax were identified from our database. All evaluations were done in non-contrast CT scans. Patients having underlying diseases that may have associated thymic abnormality were excluded. The appearance of thymus and the presence of fatty replacement were assessed. The size of thymus (length and thickness of right limb and left limb) and non-contrast CT Hounsfield unit (HU) value of thymic tissue were measured and compared in various age groups. Results: Four hundred and fifty patients were included, 262 (58.2%) were male. Mean age was 33.6 ± 17.1 years, range (3 months-80 years). The size of thymus was observed to decrease with increasing age. The mean age of complete fatty replacement in our study was 45 years. Complete fatty replacement was noted in all cases with an age of more than 60 years. The most common shape was arrowhead, and the most common location was pre-aortic and para-aortic location. Non-contrast CT HU value was maximum in infants and gradually decreased with advancing age. Conclusion: Even normal thymus can show varied appearance on CT which changes with the age of the patient being imaged. A comparison with normative data could help differentiate normal from abnormal glands to avoid unnecessary intervention.

MRI of wrist and diffusion tensor imaging of the median nerve in patients with carpal tunnel syndrome.

Objectives: Diagnosis of carpal tunnel syndrome (CTS) is based on the clinical symptoms and nerve conduction study. Magnetic resonance imaging (MRI) is non-invasive objective tool for assessing the median nerve and carpal tunnel. The purpose of this study was to evaluate MRI changes in patients with CTS, and compare them with healthy subjects. Materials and Methods: Forty-three CTS patients and 43 age matched control were included and scanned in a 3T MRI scanner. Cross-sectional areas (CSA) of median nerve were measured at the level of distal radio-ulnar joint level (CSA1), proximal row of carpal bone (CSA2), and hook of hamate (CSA3). Flattening ratio (FR) of median nerve, thickness of flexor retinaculum, median nerve signal intensity, and thenar muscles were assessed. Fractional anisotropy (FA), average diffusion coefficient (ADC), and radial diffusivity (RD) of median nerve of CTS patients were obtained from diffusion tensor imaging (DTI) and compared with those of controls. Results: Thirty-three patients (76.7%) were female. Mean duration of the pain was 7.4 ± 2.6 months. The mean CSA1 (13.2 ± 4.2 mm2), CSA2 (12.5 ± 3.5 mm2), and CSA3 (9.2 ± 1.5 mm2) in CTS patients were significantly higher compared to control group: CSA1 (10.15 ± 1.64 mm2), CSA2 (9.38 ± 1.37 mm2), and CSA3 (8.4 ± 0.9 mm2), (P = 0.001 in all). The mean FR of median nerve and thickness of flexor retinaculum were increased in CTS patients. The mean FA was reduced in CTS patients compared to control proximal to carpal tunnel and within the tunnel. Mean ADC and RD values were higher in CTS patients as compared to control for both levels. Conclusion: MRI can detect subtle changes in the median nerve and thenar muscles in CTS and may be useful in equivocal cases and to exclude secondary causes of CTS. DTI shows reduced FA and increased ADC and RD in CTS patients.