Clinical and Neurophysiological Features of Leprosy Patients with Neuropathic Pain.

Neural pain is a frequent symptom in leprosy disease. There is a paucity of data regarding neural pain diagnostics resulting in common prescriptive errors when neuritis is confused with neuropathic or mixed nociceptive-neuropathic pain. The present study identified important demographic, clinical, and neurophysiological features of 42 leprosy neuropathy patients presenting neuropathic pain (NP). During routine evaluations, patients were selected asking if they had ever experienced neural pain. Data analyses of their pain characteristics, clinical examination results, and both the Douleur Neuropathique 4 Questionnaire and Hamilton Depression Scale scores were used to classify these patients. The most common word they used to describe the sensation of pain for 25 (60%) of these patients was "burning." In the early stages of the disease and before leprosy diagnosis, 19 (45%) had already complained about NP and leprosy treatment was unable to prevent its occurrence in 15 (36%). Leprosy reactions, considered NP risk factors, occurred in 32 (76%) cases. Knowledge of typical NP characteristics could be used to develop more effective therapeutic approaches for a notoriously difficult-to-treat pain condition.

Prevalence and characteristics of neuropathic pain in leprosy patients treated years ago.

The aim of this study was to determine the prevalence of neuropathic pain, now recognized as another late complication of leprosy, and its characteristics among leprosy patients. A cross-sectional study was carried out of people treated for leprosy up to at least 5 years ago in a rural area of Ethiopia. Seventy-four patients were interviewed using the Neuropathic Pain Symptom Inventory (NPSI) questionnaire. In total, 78.9% of the patients were female with a mean age of 42.9. The mean time from initial diagnosis to the time of the study was 28.0 years, and 73.0% of patients were diagnosed over 20 years ago. Fifty-two (70.3%) reported having symptoms suggestive of neuropathic pain and the majority described the pain as burning (88.5%), electric (80.8%), stabbing (76.9%), cutting (76.9%), tingling (65.4%), squeezing (57.7%), and/or pressure (53.8%). The pain caused a severe or moderate impact on daily life in 75% and 57.7% of cases, respectively, and 92.3% suffered from disrupted sleep. Eighty percent of patients with pain (42/52) took some medication for pain relief. Neuropathic pain is common in patients treated for leprosy and in more than half of them, it causes disruption in their daily life and sleep, limiting their quality of life even more.

Association between neuropathic pain and A-waves in leprosy patients with type 1 and 2 reactions.

Neuropathic pain (NP) is a well-recognized feature of leprosy neuropathy. However, the diagnosis of NP is difficult using only clinical criteria. In the study reported here, by means of conventional nerve conduction studies, the authors sought for an association between long-latency responses and NP complaints in leprosy patients with type 1 and 2 reactions. Of the 27 ulnar nerves of leprosy patients, 18 with type 1 reaction (T1R) and 9 with type 2 reaction (T2R) were followed-up for 6 months before and after steroid treatment. Clinical characteristics of pain complaints and clinical function were assessed, as well as the presence of F- and A-waves of the ulnar nerve using nerve conduction studies. The clinical and the neurophysiologic findings were compared to note positive concordances (presence of NP and A-waves together) and negative concordances (absence of NP and A-waves together) before and after treatment. Both reactions presented a high frequency of A-waves (61.1% in T1R and 66.7% in T2R, P < 0.05) and prolonged F-waves (69.4% in T1R and 65.8% in T2R, P = 0.4). No concordances were seen between pain complaints and F-waves. However, significant concordances between NP and A-waves were observed, although restricted to the T2R group (χ(2) = 5.65, P = 0.04). After treatment, there was a significant reduction in pain complaints, as well as the presence of F- and A-waves in both groups (P < 0.05 for all comparisons). In conclusion, the presence of A-waves correlates well with pain complaints of neuropathic characteristics in leprosy patients, especially in those with type 2 reaction. Probably, such response shares similar mechanisms with the small-fiber dysfunction seen in these patients with NP, such as demyelination, intraneural edema, and axonal sprouting. Further studies using specific tools for small-fiber assessment are warranted to confirm our findings.

Association between neuropathic pain and A-Waves in leprosy patients with type 1 and 2 reactions

Neuropathic pain (NP) is a well-recognized feature of leprosy neuropathy. However, the diagnosis of NP is difficult using only clinical criteria. In the study reported here, by means of conventional nerve conduction studies, the authors sought for an association between long-latency responses and NP complaints in leprosy patients with type 1 and 2 reactions. Of the 27 ulnar nerves of leprosy patients, 18 with type 1 reaction (T1R) and 9 with type 2 reaction (T2R) were followed-up for 6 months before and after steroid treatment. Clinical characteristics of pain complaints and clinical function were assessed, as well as the presence of F- and A-waves of the ulnar nerve using nerve conduction studies. The clinical and the neurophysiologic findings were compared to note positive concordances (presence of NP and A-waves together) and negative concordances (absence of NP and A-waves together) before and after treatment. Both reactions presented a high frequency of A-waves (61.1% in T1R and 66.7% in T2R, P < 0.05) and prolonged F-waves (69.4% in T1R and 65.8% in T2R, P = 0.4). No concordances were seen between pain complaints and F-waves. However, significant concordances between NP and A-waves were observed, although restricted to the T2R group (χ(2) = 5.65, P = 0.04). After treatment, there was a significant reduction in pain complaints, as well as the presence of F- and A-waves in both groups (P < 0.05 for all comparisons). In conclusion, the presence of A-waves correlates well with pain complaints of neuropathic characteristics in leprosy patients, especially in those with type 2 reaction. Probably, such response shares similar mechanisms with the small-fiber dysfunction seen in these patients with NP, such as demyelination, intraneural edema, and axonal sprouting. Further studies using specific tools for small-fiber assessment are warranted to confirm our findings.

Neuropathic pain in leprosy.

Chronic neuropathic pain in treated leprosy has received scant attention. In this article the concept, clinical features and diagnosis of neuropathic pain are reviewed. The possible pathophysiological mechanisms, treatment challenges and research needs in this area are discussed.