Disability in leprosy is a direct consequence of damage to the peripheral nervous system which is usually worse in patients with no skin manifestations, an underdiagnosed subtype of leprosy known as primary neural leprosy. We evaluated clinical, neurophysiological and laboratory findings of 164 patients with definite and probable primary neural leprosy diagnoses. To better understand the disease progression and to improve primary neural leprosy clinical recognition we compared the characteristics of patients with short (≤ 12 months) and long (> 12 months) disease duration. Positive and negative symptoms mediated by small-fibre were frequent at presentation (∼95%), and symptoms tend to manifest first in the upper limbs (∼68%). There is a consistent phenotypic variability between the aforementioned groups. Deep sensory modalities were spared in patients evaluated within the first 12 months of the disease, and were only affected in patients with longer disease duration (∼12%). Deep tendon reflexes abnormalities were most frequent in patients with longer disease duration (p < 0,001), as well as motor deficits (p = 0,002). Damage to large fibres (sensory and motor) is a latter event in primary neural leprosy. Grade-2 disability and nerve thickening was also more frequent in cases with long disease duration (p < 0,001). Primary neural leprosy progress over time and there is a marked difference in clinical phenotype between patients with short and long disease duration. Patients assessed within the first 12 months of symptom onset had a non-length-dependent predominant small-fibre sensory neuropathy, whilst patients with chronic disease presented an asymmetrical all diameter sensory-motor neuropathy and patchily decreased/absent deep tendon reflexes.

中文翻译：

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原发性神经麻风病：临床、神经生理学和病理学表现和进展

麻风病的残疾是周围神经系统受损的直接后果，这在没有皮肤表现的患者中通常更严重，这是一种未被充分诊断的麻风病亚型，称为原发性神经麻风病。我们评估了 164 名确诊和可能的原发性神经麻风病患者的临床、神经生理学和实验室检查结果。为了更好地了解疾病进展并提高原发性神经麻风病的临床识别率，我们比较了病程短（≤ 12 个月）和长（＞12 个月）患者的特征。由小纤维介导的阳性和阴性症状在就诊时很常见（~95%），症状往往首先出现在上肢（~68%）。上述组之间存在一致的表型变异性。在疾病的前 12 个月内评估的患者中，深度感觉模式没有受到影响，并且仅在病程较长的患者中受到影响（~12%）。深部腱反射异常最常见于病程较长（p < 0,001）以及运动障碍（p = 0,002）的患者。大纤维（感觉和运动）的损伤是原发性神经麻风病的后一事件。在病程较长的病例中，2 级残疾和神经增厚也更为常见（p < 0,001）。原发性神经麻风病随着时间的推移而进展，并且病程短和病程长的患者之间的临床表型存在显着差异。在症状发作的前 12 个月内评估的患者患有非长度依赖性为主的小纤维感觉神经病变，