Electrophysiologic study in peripheral neuropathy associated with HIV infection

Clinical and electrophysiologic features in 22 patients with HIV infection are reported. Four cases had chronic demyelinating polyneuropathy, two mononeuropathy multiplex, and nine symmetrical sensory-motor polyneuropathy. Seven cases had normal clinical and electromyographic examination. Electrophysiological study had a higher diagnostic yield (68%) than clinical examination (50%) for peripheral neuropathy diagnosis. Thus, peripheral nerve abnormalities are frequent in patients with different stages of HIV infection, although their pathogenesis remains unclear. Symmetrical sensory-motor polyneuropathy is the main type of neuropathy seen in ouvert AIDS, whereas chronic demyelinating polyneuropathy was mainly diagnosed in patients with asymptomatic HIV infection as first manifestation of the disease. Axonal or demyelinating nerve damage was established according to electrophysiological criteria. Frequently a mixture of both lesions was found. Electrophysiologic study is also a good index of neuropathy evolution in HIV infection and to follow-up of nerve abnormalities after treatment.

Central motor pathways conduction after magnetic stimulation of the brain in Cockayne's syndrome

Central motor pathways conduction abnormalities after magnetic stimulation of the brain are reported in two siblings with Cockayne's syndrome. Reduced amplitude of the responses with large central conduction time were the main changes. These results are consistent with signs of diffuse white matter hypomyelination found on MRI. Conversely, only mild changes in conduction velocity of the peripheral nerves were found. Central nervous system involvement can be more severe than peripheral neuropathy in Cockayne's syndrome.

[Trichinosis. A study of a large outbreak on the Iberian peninsula]

An epidemic outbreak of trichinosis after wild boar meat ingestion was analysed. The most frequent clinical manifestations were: muscular pain, fever, periorbitary edema and conjunctivitis. Laboratory tests showed eosinophilia and increased muscular enzymes. There was no mortality. 10 patients had electromyograms, which all showed an inflammatory myopathy pattern. The one fiber study showed similar signs as those found in cases of polymyositis. There was a significant statistical relationship between intensity and duration of symptoms in the intestinal phase and eosinophils levels in peripheral blood. There was also a statistically significant relationship between CPK levels and decrease of mean duration of motor unit potential. Treatment with thiabendazole and steroids was useful. The indirect immunofluorescence test (IIT) proved an excellent method for diagnosing trichinosis.

[Recurrent amyotrophic neuralgia with an unusual clinical expression. Clinical and electrophysiological study]

Neuralgic amyotrophy (NA) is an entity with great variability in its neurological expression. The patient reported here developed symptoms of NA one year before admission, with anterior interosseous nerve palsy. At the time of examination she reports pain in the left upper limb followed by sensory loss over lateral antebrachial cutaneous nerve. Electrophysiologic examination showed signs of chronic denervation in the right anterior interosseous nerve muscles, and reduced amplitude of the sensory nerve action potential of the left lateral antebrachial cutaneous nerve. This case confirms the variety of the nerve involvement in NA, and suggests axonal focal lesions of nerve fascicles or individual peripheral nerve affectation.

[Evaluation of respiratory muscle function (maximal respiratory pressures) in myasthenia gravis]

In myasthenia gravis (MG) the status of respiratory function has a paramount importance and a careful evaluation is recommended. The weakness of respiratory muscles has been demonstrated in several studies. However, a reliable simple method for the evaluation of this muscular group was lacking until recently, when the usefulness of the maximum respiratory pressures, expiratory (MEP) and inspiratory (MIP), was demonstrated. We evaluated with this method a series of 23 patients with a diagnosis of MG (16 females and 7 males), with a mean age of 46 years (22-68 years), clinically stable and without symptomatic dyspnea. They were distributed in: grade I (5), grade II A (12), and grade II B (6). All of them were evaluated with flow-volume curves, pletysmography, gas transfer, MEP and MIP. The resulting values were then correlated with the expected ones, a reduction greater than one SD being considered as abnormal. The results showed that respiratory function was normal without a restrictive pattern. However, the force of respiratory muscles was reduced in the following proportions of patients in the different groups: grade I: MIP 40%, MEP 60%; in grades II A and II B both MEP and MIP were reduced in 84% of patients. When a statistical comparison with the expected values was carried out it was found that MEP and MIP, considered as a group, were reduced to 53% of the expected values (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Chronic inflammatory demyelinating polyneuropathy as first manifestation of human immunodeficiency virus infection

We studied three patients who were admitted to the hospital because of progressive weakness without other systemic signs or symptoms. All three cases were young males who had been intravenous drug user for many years. Electrophysiologic study showed prolonged distal latencies and marked slowing of motor and sensory conduction velocities, consistent with primary demyelination. Nerve biopsy also showed signs of demyelination. Antibodies against HIV in CSF and blood were detected during the diagnostic evaluation. Clinical and electrophysiological studies improved in two cases after prednisone administration. Patients with predominant motor demyelinating neuropathies and risk factors should be screen for HIV infection.

[Multifocal polyneuropathy with persistent conduction blockage. A new subset of chronic inflammatory polyneuropathies]

Recently a subset of chronic demyelinating inflammatory polyneuropathies with asymmetrical involvement limited to upper limbs, at least at the onset, resembling a multifocal mononeuropathy has been described. Electrodiagnostic testing disclosed multifocal CB outside the common entrapment sites has been described. We report a 55 years old man with a 4 years history of paresis, numbness, fasciculations, myokymia, cramps and mild amyotrophy. Electrophysiological evaluation showed proximal multifocal conduction block and abundant spontaneous activity as fasciculations, myokymia and scarce denervation activity. The importance of taking into account this entity in the differential diagnosis of patients with suspected mononeuritis multiplex or motoneuron disease is emphasized. The nosologic place of this entity is also discussed.

Conduction velocity in human muscle fibers in situ. Study in upper and lower limbs in healthy adults

The muscle fibers of the human biceps brachii and vastus medialis muscles were stimulated with low voltages in their distal portion by means of monopolar needles in 50 healthy adults. The electrical activity was recorded proximally by means of a SFEMG electrode. The conduction velocity of the muscle fibers in situ calculated with this method had a Gaussian distribution for both muscles, showed values slightly higher in males than in females, did not decrease significantly with ageing, and was significantly related to limbs perimeter. The recorded potentials and their propagation velocity were the same before than after curarization. The possible interest of the method for testing the muscle fiber function and size in pathological conditions of the nerve and muscle is suggested.

Single fibre and quantitative EMG study in acute stage of human trichinosis

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[Recurrent Miller-Fisher syndrome associated with brachial neuritis]

The clinical and electrophysiological evolution of a 24-year-old patient with Miller-Fisher's syndrome and findings of mild peripheral neuropathy in the electromyographic study is reported. The patient had been treated six years previously for a similar disease and he recovered in 2 months. During the plasmapheresis therapy of the second episode he developed pain and weakness of the left shoulder girdle, and the EMG was consistent with bilateral brachial neuritis. The disease had improved clinically after 6 weeks, except for supracapsular brachial neuropathy; this territory remained denervated after 3 months of evolution. A diagnosis of Crohn's disease had been made between both episodes. The discussion focuses on the rarity of recurrent forms of Miller-Fisher's syndrome and the association of the reported case with brachial neuritis and Crohn's disease.

Electrophysiologic follow-up in Whipple's disease

Neurologic and electrophysiologic findings in a 57-year-old man with Whipple's disease are reported. The patient had severe proximal weakness and weight loss of more than 20 kg. Conventional electromyography and nerve conduction studies suggested mild neuropathy in distal segments of lower limbs and myopathy in proximal muscles. Automatic analysis of the electromyogram in proximal muscles was consistent with myopathy. Conduction velocity of muscle fibers in situ showed low propagation velocity of the impulse. Weakness, weight loss, and all the electrophysiologic parameters improved after treatment, including a compression of the peroneal nerve at the knee, perhaps related to weight loss (slimmer's paralysis).

Slimmer's paralysis: electrophysiological evidence of compressive lesion

A 14-year-old girl developed right peroneal nerve palsy following diet for weight reduction. Peroneal neuropathy started after sitting and leg-crossing. The main electrophysiologic findings showed a severe slowing of conduction velocity in the above-to-below capitulum fibulae segment and a striking reduction in the size of the compound motor action potential when the nerve was stimulated above the knee. These features are consistent with focal demyelination and conduction block of the nerve fibres. The left peroneal nerve showed the same results but less severe. There were no electrophysiological signs of subclinical polyneuropathy. Examination after 3 months was normal. The clinical and electrophysiological features in this case support the compressive origin of the peroneal neuropathy in slimmer's paralysis.

Electrophysiologic study in benign human botulism type B

Conventional electromyography (EMG) and single fiber EMG (SFEMG) were performed in a 64-year-old diabetic woman with mild type B botulism. The main clinical signs were autonomic dysfunction and cranial nerves paresis. Conventional EMG was normal, except for small changes that were consistent with mild mixed peripheral neuropathy in the lower limbs and were related to diabetes. Repetitive stimulation and results of single stimulus before and after full effort were normal. SFEMG showed increased jitter and impulse blocking in clinically normal muscles. The jitter was frequency dependent and improved at a higher innervation rate. Impulse blocking in potentials with only slightly increased jitter was found. The follow-up showed improvement of the jitter in agreement with clinical recovery. Jitter abnormalities were recorded after 16 weeks, when clinical signs of botulism had been reversed to normal. Motor unit fiber density increased progressively, and on examination at 8 weeks, some potentials showed very high jitter values. Both findings might suggest new endplate formation, perhaps due to ultraterminal sprouting development.