Muscle involvement in leprosy: study of the anterior tibial muscle in 40 patients

Abstract

-The involvement of skeletal striated muscle in leprosy is considered secondary due to peripheral neuropathy, but some studies point it to a primary muscle lesion. In order to investigate the muscle involvement in leprosy, we studied 40 patients (lepromatous 23, tuberculoid 13, borderline 2 and indeterminate 2). The motor nerve conduction of the peroneal nerves had a reduction of the velocity, decreased compound muscle action potential and sometimes absence of potentials. The electromyographic study of the anterior tibial muscle showed signs of recent and chronic denervation in 77.5% of the cases and no myopathic potentials. The anterior tibial muscle biopsy revealed denervation in 45% of the cases, interstitial inflammatory myopathy in 30% and mixed (myopathic and neuropathic) pattern in 12.5%. Acid fast bacillus was detected in 25% of the cases, always in the interstitial tissue. Inflammatory reaction was present in the interstitial space and in patients with the lepromatous type. The histological findings clearly defined the presence of the so-called "Leprous Interstitial Myositis" on the top of denervation signs.KEY WORDS: leprosy, skeletal muscle, muscle biopsy, myositis.Alterações musculares na lepra: estudo do músculo tibial anterior em 40 pacientes RESUMO -O envolvimento do músculo estriado na lepra é considerado secundário à lesão dos nervos periféricos, mas alguns estudos relataram acometimento muscular primário. A fim de verificar esta controvérsia estudamos 40 pacientes com lepra, sendo 23 da forma lepromatosa, 13 da tuberculoide, 2 borderline e 2 indeterminada. Realizamos a neurocondução do nervo peroneiro, junto com eletromiografia e biópsia do músculo tibial anterior. Encontramos redução de velocidade de condução, da amplitude e algumas vezes ausência de potenciais no nervo peroneiro. A eletromiografia do tibial anterior mostrou sinais de desinervação recente e crônica em 77,5% dos casos e não foi encontrada evidência de padrão "miopático". A biópsia do músculo tibial anterior revelou desinervação em 45% dos casos, miopatia inflamatória intersticial em 30% e padrão misto (miopático e neuropático) em 12,5%. Bacilos alcool-ácido resistentes foram encontrados em 25% dos casos, sempre localizados no perimisio e endomisio. Na forma lepromatosa, a reação inflamatória estava presente no espaço intersticial. Os dados histológicos claramente definiram a presença de "Miosite Lepromatosa Intersticial" sobreposta às alterações histológicas encontradas em desinervação. PALAVRAS-CHAVES: lepra, músculo esquelético, biópsia muscular, miosite.Leprosy is a chronic infection illness caused by the Myobacterium leprae (M.leprae) that preferably attacks peripheral nerves. This disease is endemic all over the world, specifically in Brazil, and it is considered the commonest cause of treatable peripheral neuropathy [1][2][3] .

Avaliação Eletromiográfica Em Pacientes Portadores De Hanseníase Com Quadro De Neuropatia Periférica

“…Esses dados vão de encontro a um estudo recente de Veras [9], que encontrou níveis diminuídos de sinais eletromiográficos no músculo tibial anterior quando comparando portadores de hanseníase e indivíduos saudáveis. Outros estudos eletromiográficos prévios que avaliaram músculos do membro inferior em pacientes com hanseníase também verificaram redução de atividade muscular na maioria dos casos, nos quais 77,5% apresentavam algum sinal de denervação [14][15][16][17][18].…”

An Unusual Presentation of Lepromatous Leprosy

“…Occasionally musculoskeletal involvement precedes characteristic cutaneous and / or neural involvement [4]. The involvement of skeletal muscle in leprosy is considered secondary to peripheral nerve involvement, but some studies point to a primary muscle lesion [5]. This primary muscle involvement has been variably termed 'lepromatous myositis', 'leprous interstitial myositis' or leprous nodular interstitial myositis' [5].…”

“…The involvement of skeletal muscle in leprosy is considered secondary to peripheral nerve involvement, but some studies point to a primary muscle lesion [5]. This primary muscle involvement has been variably termed 'lepromatous myositis', 'leprous interstitial myositis' or leprous nodular interstitial myositis' [5]. Acid fast bacilli (AFB) has been demonstrated in the interstitium, inside macrophages, vessel walls and intramuscular nerves [6].…”

Degree of disability, pain levels, muscle strength, and electromyographic function in patients with Hansen's disease with common peroneal nerve damage

“…Muscle strength levels and electromyographic signal response can decrease in patients with leprosy due to possible nerve damage caused by the leprosy bacillus 16,17 .…”