Compound Nerve Action Potential of Common Peroneal Nerve and Sural Nerve Action Potential in Common Peroneal Neuropathy

To enhance the accuracy for determining the precise localization, the findings of the compound nerve action potentials (CNAPs) of the common peroneal nerve (CPN) were investigated in patients with common peroneal mononeuropathy (CPM) in the knee, and the sural sensory nerve action potentials (SNAPs) were also analyzed. Twenty-five patients with CPM in the knee were retrospectively reviewed. The findings of the CNAPs of the CPN recorded at the fibular neck and the sural SNAPs were analyzed. The lesion was localized at the fibular head (abnormal CNAPs) and at or distal to the fibular head (normal CNAPs). Seven patients were diagnosed as having a lesion at or distal to the fibular neck, and 18 cases were diagnosed as having a fibular head lesion. The sural SNAPs were normal in all the cases of lesion at or distal to the fibular neck. Among 18 cases of fibular head lesion, the sural SNAPs were normal in 7 patients: two cases of conduction block and 5 cases of mild axon loss. Eleven patients showed abnormal sural SNAPs. Of those, 9 cases were severe axon loss lesions and 2 patients were diagnosed as having severe axon loss with conduction block. The recording of the CNAPs may enhance precise localization of CPM in the knee. Moreover, the sural SNAPs could be affected by severe axonal lesion at the fibular head.

Near nerve potential of sural nerve in leprosy

Na hanseníase, as fibras de pequeno calibre são acometidas antes que as fibras mais grossas, ocasião em que o estudo da condução torna-se anormal. Neste estudo, utilizou-se a técnica de registro com eletrodos justa-nervo com a finalidade de aumentar a precocidade e a acurácia diagnóstica, devido à sua capacidade de detectar potenciais oriundos de fibras com cerca de 3-6 mm. Contrário às nossas expectativas, o componente principal do potencial sensitivo do nervo sural foi anormal em todos os pacientes, enquanto a velocidade de condução mínima foi normal ou discretamente alterada em 3 pacientes. Além disso, os resultados são sugestivos de degeneração axonal e não mielinopatia, como seria esperado em uma doença que compromete inicialmente a bainha de mielina. Para um melhor entendimento da fisiologia e fisiopatologia, e para aumentar a precocidade diagnóstica, é fundamental estudar casos bem precoces e correlacionar os dados neurofisiológicos com a respectiva anatomia patológica.

A case of hereditary sensory and autonomic neuropathy (HSAN) type II.

We describe a case of hereditary sensory and autonomic neuropathy (HSAN) type II in a child with a penetrating foot ulcer, acral sensory impairment, and anhidrosis. This is the first documentation of HSAN in Sri Lanka.

The usefulness of minimal F-wave latency and sural/radial amplitude ratio in diabetic polyneuropathy

The possibility of whether minimal F-wave latency and a simple ratio between the sural and superficial radial sensory response amplitudes may provide a useful electrodiagnostic test in diabetic patients was investigated in this report. To evaluate the diagnostic sensitivity of minimal F-wave latency, the Z-scores of the minimal F-wave latency, motor nerve conduction velocity (MCV), amplitude of compound muscle action potentials (CMAP), and distal latency (DL) of the median, ulnar, tibial, and peroneal nerve were compared in 37 diabetic patients. For the median, ulnar, and tibial nerves, the Z scores of the minimal F-wave latency were significantly larger than those of the MCV. In addition for all four motor nerves, the Z scores of the minimal F-wave latency were significantly larger than those for the CMAP amplitude. Furthermore, 19 subjects showing abnormal results in the standard sensory nerve conduction study had a significantly lower sural/radial amplitude ratio (SRAR), and 84% of them had an SRAR of less than 0.5. In conclusion, minimal F-wave latency and the ratio between the amplitudes of the sural and superficial radial sensory nerve action potential are sensitive measures for the detection of nerve pathology and should be considered in electrophysiologic studies of diabetic polyneuropathy.

Electrophysiological findings in newly diagnosed non-insulin-dependent diabetics: a prospective study

This study reports the electrophysiological findings in patients with newly diagnosed non-insulin-dependent diabetes mellitus [NIDDM] studied in the Neurodiagnostic Laboratory of the King Fahd Hospital of the University [KFHU], Al-Khobar, Saudi Arabia. Twenty-nine patients [22 males, 7 females, mean ages 47 and 37 years, respectively] were studied within four weeks of establishing the diagnosis. They were all given nerve conduction studies by the same examiner. Comparison was made with data from a group of 64 normal control subjects. In the study patients, the mean distal sensory peak latency in milliseconds [ms] +/- standard deviation [SD] was 3.5 +/- 0.41 ms in 35 median nerves, 3.2 +/- 0.72 ms in 35 ulnar nerves, 1.9 +/- 0.34 ms in 23 superficial radial nerves and 3.5 +/- 0.61 in 36 sural nerves. The mean distal motor latency +/- SD was 4.6 +/- 0.95 ms in 39 median nerves, 3.5 +/- 0.58 ms in 38 ulnar nerves, 4.8 +/- 1.02 ms in 44 tibial nerves and 6.0 +/- 1.08 ms in 36 peroneal nerves. The electromyogram examination was performed on 24 patients and showed evidence of denervation and/or chronic reinnervation in seven [29%]. The frequency of abnormalities in the studied peripheral nerves was 60% for median, 63% ulnar, 33% peroneal, 16% tibial and 8% sural

Doença de Charcot-Marie-Tooth: estudos eletromiográficos em 45 pacientes / Charcot-Marie-Tooth disease: electromyographic studies in 45 patients

Foi realizada eletroneuromiografia em 45 pacientes com doença de Charcot-Marie-Tooth (CMT). A classificaçäo em tipo I e tipo II da doença de CMT foi feita com base na neuroconduçäo motora do mediano e do ulnar. Assim 11 pacientes eram do tipo I e 34 eram do tipo II. NO tipo I näo houve relaçäo entre a queda da VCN motora do ulnar e mediano com o quadro clínico da doença. Devido a ausência do potencial de açäo sensitivo (PAS) do nervo sural em muitos casos, achamos impossível a classificaçäo da doença pela neuroconduçäo deste nervo. Muitos pacientes com doença de CMY II, tinham neuroconduçäo normal, porém a amplitude do PAS do sural estava ausente ou reduzida, mostrando tratar-se realmente de doença do nervo periférico e näo da ponta anterior da medula. Achamos que o estudo da neuroconduçäo é o mais importante na classificaçäo da doença de CMT

Neuropatia pelo óxido de etileno / Neuropathy induced by ethylene oxide

O óxido de etileno (O.E.) é um gás altamente reativo e penetrante, que tem se tornado um dos principais esterilizantes devido à possibilidade de poder ser usado em baixas temperaturas, tornando-se ideal para esterilizar materiais sensíveis ao calor. Estudos em animais têm demonstrado a neurotoxicidade do O.E. em diversas espécies, porém, somente após 1979, trabalhos têm relatado sua neurotoxicidade em humanos. Analisamos dez casos de polineuropatia sintomática induzida pelo O. E. referidos na literatura. Todos os trabalhos relacionam, consistentemente, o desenvolvimento de polineuropatia sensitivo-motora do tipo axonal com a exposiçäo ao gás, no entanto também mostram clara tendência para remissäo do quadro clínico após interrupçöes da exposiçäo

Neuropatia sensitiva aguda idiopática: relato de caso / Acute idiopathic sensory neuropathies: a case report

As neuronopatias sensitivas caracterizam-se por parestesis, ataxia sensitiva e arreflexia sem comprometimento motor, devidas a lesäo no gânglio sensitivo dorsal, com degeneraçäo axonal e do cordäo posterior da medula espinhal. Descrevemos o caso deuma paciente de 21 anos de idade, cuja doença se iniciou de modo agudo com parestesias distais, astasia, abasia e hiporreflexia. Força muscular normal. A conduçäo nervosa sensitiva estava ausente e a motora, discretamente reduzida. LCR com 2 leucócitos/mm3 e 1,06 g/dL de proteínas. A biópsia de músculo evidenciou atrofia de fibras tipo 2 e a biópsia do nervo sural, desmielinizaçäo axonal. Tratada com prednisona, permaneceu discreto déficit proprioceptivo nos pés após um ano e meio de evoluçäo. Säo discutidos aspectos clínicos do envolvimento dos gânglios sensitivos dorsais, possíveis etiologia tóxicas, a relaçäo com neoplasias e com a síndrome de Sjogren