Clinical characteristics of neuropathic pain in leprosy and associated somatosensory profiles: a deep phenotyping study in India

Abstract

This study investigated the clinical characteristics and somatosensory profiles of patients suffering from leprosy in Mumbai, India. A cross-sectional deep profiling study was conducted in 86 patients with leprosy (with and without pain) using an extensive battery of phenotyping measures including structured clinical examination, psychological state (General Health Questionnaire [GHQ-12]), and a quality-of-life condition-specific instrument (Brief Pain Inventory—short form). Quantitative sensory testing was performed according to the protocol of the German Research Network on Neuropathic Pain (DFNS) to assess the somatosensory profiles in the ulnar nerve innervation territory of all participants (dorsum of the hand). Reference data from 50 healthy Indian subjects were within the range of published DFNS values. Somatosensory profiles in leprosy patients with clinically or electroneurographically diagnosed neuropathy (with and without pain) revealed a profile of sensory loss to thermal and tactile stimuli combined with preservation of vibration and deep pressure detection. Sensory gain phenomena were not generally observed in patients with leprosy. In the group of subclinical neuropathy, a high degree of impaired thermal sensation was found, which could be clinically deployed to enhance identification of leprosy neuropathy at an early stage. Quantitative sensory testing can effectively document leprosy-associated neuropathy but does not distinguish between patients with or without pain. Patients with leprosy and neuropathic pain reported a poor quality of life and less psychological well-being compared with the pain-free patients with leprosy neuropathy.

Mechanical detection and pain thresholds: comparability of devices using stepped and ramped stimuli

“…For these reasons, they may be used more broadly in resource-limited settings to assess MDT in accordance with the DFNS protocol. 12 When used to estimate MPT, the findings do not match the DFNS reference data under all conditions, and the varying filament diameters do not allow a clear distinction between activation of tactile receptors vs nociceptors. 9 …”

Sensory and pain modulation profiles of ongoing central neuropathic extremity pain in multiple sclerosis

“…These phenotypes are mainly characterized by (a) loss of thermal and mechanical detection—‘sensory loss’; (SL), (b) intact sensory function, often combined with thermal hyperalgesia or allodynia—‘thermal hyperalgesia’ (TH); (c) loss of thermal detection, but not mechanical detection, accompanied by mechanical hyperalgesia or allodynia—‘mechanical hyperalgesia’ (MH); and (d) a largely normal sensory profile resembling that of healthy subjects—‘healthy sensory profile’ (HP; Vollert et al., 2017). These phenotypes have since been described in a wide range of neuropathic pain syndromes, such as small‐fibre neuropathy (Üçeyler et al., 2018), entrapment neuropathies (Tampin et al., 2018) and leprosy (Haroun et al., 2019) and have been linked to mechanistic studies in human surrogate models of pain (Vollert et al., 2017). The frequency of each phenotype was compared between pain‐suffering and pain‐free MS patients.…”

Assessment of neuropathic pain in leprosy patients with relapse or treatment failure by infrared thermography: A cross-sectional study

“…In this study, most patients were already in an advanced stage of the disease, especially those in the PWP group, with significant motor loss (p = 0.001) and a predominance of multiple asymmetric mononeuritis (p = 0.045). The highest degree of disability was related to pain and the general poor perception of health [ 5 ]; although no significant difference was shown between the groups, the prevalence of disability grade II was high (37.9%) in the PWP group. These findings confirm that NP is a late complication of leprosy [ 39 ].…”

“…This neural impairment often leads to changes in sensory, motor, and autonomic function [ 4 ]. Leprosy peripheral neuropathy may occur before, during, or after treatment with multidrug therapy (MDT) [ 5 ].…”

“…As pain is a subjective symptom, difficult to measure, and involves physical and psychic aspects, making the diagnosis is sometimes a challenge [ 7 ]. It is important that NP is well diagnosed and adequately treated, since it is associated with low indices of quality of life and general health status [ 8 , 5 ].…”