El estudio de Cohortes Infir: evaluación de la neuropatía sensitiva y motora en la lepra / No disponible

Objetivo: Comparar los distintos métodos para detector la neuropatía periférica en la lepra y evaluar la validez de la prueba de monofilamente (MF) y la técnica del músculo voluntario (VMT) como pruebas estándar de la función neural. Diseño: Un estudio multicéntrico de 303 pacientes de lepra multibacillar (MB). Métodos: Se dieron de alta en el estudio nuevos pacientes MB que requieren un tratamiento completo de MDT en dos clínicas para pacientes de lepra ambulatorios del norte de la India. Los controles fueron individuos sin lepra o condiciones neurológicas, que atendían los departamentos dermatológicos de las mismas clínicas. Se evaluó electrofisiológicamente la función neural mediante parámetros estándar para la conducción neural sensitiva y motora (NC), detección de umbrales térmicos (W/CDT), umbrales de percepción vibratoria, dinamometría, MF y VMT. Estos últimos definen los resultados de detección sensitivo y motor. Resultados: 115 pacientes presentaron deterior neural o una reacción reciente en el momento del diagnóstico. Los amplificados sensitivos y motores y WDT eran las pruebas más frecuentemente anormales. De entre todos los nervios evaluados, el safeno externo y nervio tibial posterior. En el nervio cubital, se detectaron anormalidades en el 25% de los individuos y las amplitudes en el 40%. Las velocidades de conducción del cubital sobre el codo resultaron anormales en el 39% y las amplitudes en el 32%. Las WDT se detectaron más frecuentemente que las CDT en todos los nervios evaluados. Los umbrales para todos los parámetros difieren significativamente entre controles y pacientes, mientras que las diferencias eran mínimas entre pacientes con o sin reacción. Se detectó una buena correlación entre los resultados MF y las latencias y velocidades sensitivas (concordancia del 80% para el nervio cubital). Sin embargo, una proporción de los nervios con resultados MF anormales resultaron normales en una o más de las pruebas o viceversa. La concordancia para el nervio cubital entre la VMT y las velocidades de conducción motora resultó buena, pero para los nervios medianos y peroneales, la proporción de los que presentan detección de la VMT entre los afectados por conducción motora resultó baja. Conclusiones: La concordancia entre los monofilamentos y otras pruebas de función sensitiva fue aceptable, apoyando la validez de los monofilamentos como test de cribaje para la función sensitiva. La concordancia entre VMT y conducción motora resultó buena para el cubita, pero muy pocos nervios medianos y peroneales con conducción anormal presentaron VMT anormal. Se requiere un test manual para la función motora más sensible. De entre los test de evaluación neural. De entre las pruebas neurológicas ensayadas, las más afectadas eran las amplitudes NC y la sensación de calor. Por tanto, los estudios sobre conducción neural y medidas WDT parecen ser las más prometedoras para la detección precoz de la neuropatía de la lepra. El patrón de la concordancia entre la afectación de la lepra sensibilidad térmica y táctil no apoya la hipótesis de que la neuropatía de pequeñas fibras sugiere preceder la afectación de las fibras mayores. La sensación de calor está más frecuentemente afectada que la de frío. Esto podría decir que las fibras C desmielinizadas están más frecuentemente afectadas que las fibras pequeñas Ad mielinizadas

Aim: To compare different method(s) to detect peripheral neuropathy in leprosy and to study the validity of the monofilament test (MF) and the voluntary muscle test (VMT ) as standard test of nerve function. Design: A multi-centre cohort study of 303 multibacillary (MB) leprosy patients. Methods: Newly registered MB patients requiring a full course of MDT were recruited in two leprosy outpatient clinics in North India. Controls were people without leprosy or neurological conditions, attending the dermatological outpatient departments of the same clinics. Never function was evaluated electrophysiologically using standard parameters or sensory and motor nerve conduction (NC) testing, warm and cold detection thresholds (W/CDT), vibration perception thresholds, dynamometry, MF and VMT. The latter two defined the outcomes of sensory and motor impairment. Results 115 patients had never damage or a reaction recent onset at diagnosis. Sensory and motor amplitudes and WDTs were the most frequently abnormal. Among the nerves tested, the sural and posterior tibial were the most frequently impaired. In the ulnar nerve, sensory latencies were abnormal in 25% of subjects; amplitudes in 40%. Ulnar above-elbow motor conduction velocities were abnormal in 39% and amplitudes 32%. WDTs were much more frequently affected ficanty between controls and patients, while only some differed between MF results wever, a proportion of nerves with abnormal MF results tested normal on one or more of the other test or vice versa. Concordance between VMT and motor conduction velocities was good for the ulnar nerve, but for the median and peroneal nerves, the proportion impaired by VMT out of those with abnormal motor conduction was very low. Conclusions: Concordance between monofilaments and other sensory function test results was good, supporting the validity of the monofilaments as standard screening test of sensory function. Concordance between VMT results and motor nerve conduction was good for the ulnar nerve, but vey few median and peroneal nerves with abnormal conduction had an abnormal VMT. A more sensitive manual motor test may be needed for these nerves. Of the nerve assessment tests conducted, NC amplitudes and warm sensation were the most frequently affected. There-fore, nerve conduction studies and WDT measurements appear to be most promising tests for early detection of leprous neuropathy. The pattern of concordance between tactile and thermal sensory impairment failed to support the hypothesis that small fibre neuropathy always precedes large fibre damage. Warm sensation was more frequently affected that cold sensation. This could indicate that unmyelinated C fibres are more frequently affected than small myelinated Ad fibres

Retos del Deterioro neural en Lepra / No disponible

La base del deterioro neural en la lepra es la tendencia del Mycobacterium leprae de invadir las c¨¦lulas Schawann. El ¦Á¦Â-distroglicano sobre la membrana basal de las c¨¦lulas Schawann se une a la alminina ¦Á2, que a su vez se une a receptores situados sobre la superficie del M. leprae, incluyendo una prote¨ªna tipo histona y el glicol¨ªpido fen¨®lico-I. Cuando se observ¨® que este deterior neural durante las reacciones de reversi¨®n estaba asociado con el repentino incremento de la hipersensibilidad de tipo retardado frente a determinados ant¨ªgenos de M. leprae liberado por las c¨¦lulas Schawann, se postul¨® que se afecta el nervio como testigo inocente de la respuesta inmunol¨®gica. Esto favorece la administraci¨®n de terapia farmacol¨®gica basada en la inmunosupresi¨®n combinado con la anti-micobacteriana. La lisis xe las c¨¦lulas Schawann con determinantes antig¨¦nicos M.leprae por c¨¦lulas T CD4+ activadas y la interaci¨®n de los receptores tipo Toll de las c¨¦lulas Schawann con el M.leprae son mecanismos adicionales tambi¨¦n implicados en el deterioro neural. La persistencia de ant¨ªgenos M. Leprae en las lesiones locales despu¨¦s de la administraci¨®n de MDT es un factor de riesgo importante para las reacciones tard¨ªas. A pesar de los grandes adelantos en el suministro global de MDT, el diagn¨®stico precoz, junto al tratamiento eficaz de la enfermedad y el deterioro neural asociado con ¨¦l siguen constituyendo un desaf¨ªo para los servicios sanitarios. La disminuci¨®n de la prevalencia como consecuencia de la MDT no debe ser tomada como indicador de que los desaf¨ªos que presenta esta enfermedad est¨¢n disminuyendo ya que mientras no se controle el deterior neural y los ¨ªndices de nuevas detecciones no disminuyan hay que seguir en guardia

The basis of nerve damage in leprosy is the unique tendency of Mycobacterium leprae to invade Schwann cells. ¦¡¦Â-Dystroglycan on the basement membrane of Schwann cells binds to laminin ¦Á2 in turn binding to receptors on the M. leprae surface, comprising a histone-like protein and phenogly-1colipid-1. When never damage during reversal reactions was found tio be associated with an abrupt increase in delayed type hypersensitivy against M. leprae antigenic determinants relased form Schwann cells, it suggested that the nerve is damaged as an innocent bystander during the immune response. This strongly influenced the introduction of therapy based on immunosuppression combined with continued anti-mycobacterial medication. Lysis of Schwann cells presenting M. leprae antigenic determinants by activated CD4 + T cells and interaction of M. leprae with Toll-like receptors on Schawann cells are additional mechanisms implicated in nerve damage. Persistence of M. leprae antigen in local lesions after regular multiple drug therapy (MDT) is an important risk factor for late reactions. In spite of significant advances in the provision of MDT globally, early diagnosis, together with effective treatment of the disease and associated serve damage at initial presentation remains a major challenge for the health services. Reduced prevalence as a result of MDT should not to be taken to indicate that the challenges of leprosy control are diminished as long as nerve damage is not controlled and new case detection rates are not declining

Neurotrophic factors and their receptors in human sensory neuropathies.

Neurotrophic factors may play key roles in pathophysiological mechanisms of human neuropathies. Nerve growth factor (NGF) is trophic to small-diameter sensory fibers and regulates nociception. This review focuses on sensory dysfunction and the potential of neurotrophic treatments. Genetic neuropathy. Mutations of the NGF high-affinity receptor tyrosine kinase A (Trk A) have been found in congenital insensitivity to pain and anhidrosis; these are likely to be partial loss-of-function mutations, as axon-reflex vasodilatation and sweating can be elicited albeit reduced, suggesting rhNGF could restore nociception in some patients. Leprous neuropathy. Decreased NGF in leprosy skin may explain cutaneous hypoalgesia even with inflammation and rhNGF may restore sensation, as spared nerve fibers show Trk A-staining. Diabetic neuropathy. NGF is depleted in early human diabetic neuropathy skin, in correlation with dysfunction of nociceptor fibers. We proposed rhNGF prophylaxis may prevent diabetic foot ulceration. Clinical trials have been disappointed, probably related to difficulty delivering adequate doses and need for multiple trophic factors. NGF and glial cell line-derived neurotrophic factor (GDNF) are both produced by basal keratinocytes and neurotrophin (NT-3) by suprabasal keratinocytes: relative mRNA expression was significantly lower in early diabetic neuropathy skin compared to controls, for NGF (P < 0.02), BDNF (P < 0.05), NT-3 (P < 0.05), GDNF (< 0.02), but not NT4/5, Trk A or p75 neurotrophin receptor (all P > 0.05). Posttranslational modifications of mature and pro-NGF may also affect bioactivity and immunoreactivity. A 53 kD band that could correspond to a prepro-NGF-like molecule was reduced in diabetic skin. Traumatic neuropathy and pain. While NGF levels are acutely reduced in injured nerve trunks, neuropathic patients with chronic skin hyperalgesia and allodynia show marked local increases of NGF levels; here anti-NGF agents may provide analgesia. Physiological combinations of NGF, NT-3 and GDNF, to mimic a 'surrogate target organ', may provide a novel 'homeostatic' approach to prevent the development and ameliorate intractable neuropathic pain (e.g., at painful amputation stumps).

Plantar ulcers in hereditary sensory neuropathy. A plea for conservative treatment.

Hereditary sensory neuropathy is a rare syndrome characterized by the occurrence, in childhood or early adult life, of perforating ulcers of the feet, lightning pains, and loss of cutaneous sensation and tendon reflexes in the lower extremities. Three patients with hereditary sensory neuropathy were family members. Trophic ulcers may be caused by diseases other than diabetes, syphilis, and leprosy.

[Pseudoscleroderma and sclerodermiform states]. / Pseudo-sclérodermies et états sclérodermiformes.

Pseudo-scleroderma should not be confused with true scleroderma, the prognosis of which is unpredictable and often serious. Progressive acrosclerosis must be differentiated from Raynaud's disease, congenital or hereditary disorders of unknown aetiology: Werner's syndrome, acrogeria and progeria; Rothmund-Thomson's syndrome, Steinert's disease, phenylketonuria, disorders of glycogen metabolism; metabolic disorders: mutilating acropathies, scleromyxoedema, porphyria cutanea tarda; occupational and iatrogenic disorders: acroosteolysis, toxic epidermic syndrome (Spain), scleroderma-like change induced by bleomycin, chronic graft-versus-host disease; and leprosy. Acute diffuse scleroderma should not be confused with Buschke's scleroedema, sclerema neonatorum, systemic amyloidosis and scleroderma-like changes in hypothyroidism. Linear pseudo-scleroderma is suggested by the following scleroderma-like conditions: facial hemiatrophy, acrodermatitis atrophicans, melorheostosis, pseudo-scleroderma after corticosteroid injection, and cutaneous lesions in carcinoid syndrome. Scleroderma in plaque must be differentiated from hypodermitis sclerotisans, panatrophy and localized lipoatrophies, hypodermitis after vitamin K injection, basal cell carcinoma, necrobiosis lipoidica, vitiligo, chronic radiodermatitis, cutaneous lymphatic invasion. Scleroderma-like changes after drug injection (vitamin B12, progestin), anetoderma barely resemble morphea guttata.