Polineuropatía paraneoplásica con anticuerpos anti-anfifisina

Paraneoplastic neurological syndromes consist of a dysfunction of any part of the nervous system, in isolation or in combination, caused by a malign neoplasia, but not by the direct tissular or metastasic invasion of the tumour. Their pathogeny is explained by immunological mechanisms and they are characterised by the presence of high rates of antibodies in serum and cerebrospinal fluid. We present the case of a patient with a sensitive neuropathy that produced ataxia, and who suffered from a poorly differentiated adenocarcinoma of the lung, in whom the search for antineuronal antibodies was positive for antiamphiphysin antibodies, supporting the diagnosis of paraneoplastic polyneuropathy.

[Conduction and origin of evoked potentials in the somesthetic pathway (author's transl)]

In 24 normal subjects, sensory conduction velocity increased progressively from the distal to the proximal segments of the peripheral nervous system. In the central somatosensory pathway, sensory impulses slowed down at a rate much greater than what could be expected from just the three known synaptic delays (1 ms each) in medulla, thalamus and somatosensory cortex. The present data point to the special characteristic of conduction in the thalamo-cortical axons as the main cause for the deceleration observed in the central somatosensory pathway. A conduction velocity of 14 m/s has been calculated for this last segment. However it is also possible that sensory conduction in the medial lemniscus might be reduced in relation to the conduction values in the peripheral segments.

[Alterations of previous potentials of somatosensory cerebral evoked potential after lesions of the brain-stem (author's transl)]

The characteristics of previous potentials of somatosensory evoked potential in 12 patients with lesions of the brain-stem and in 24 normal individuals have been studied. Lesions of the brain-stem were confirmed by means of computerized axial tomography, arteriography or necropsy. According to data reported by other authors somatosensory evoked potential is anteceded by three previous potentials with central latencies of 10, 12, and 14 milliseconds. Brain-stem lesions which do not involve the medial lemniscus showed normal potencials, while extensive lesions of the protuberance abolish P-12 potential and increase central latencies of P-14 and somatosensory evoked potential. P-12 potential originates in the medial lemniscus and P-14 potential in the thalamic nuclei. The present results confirm the interest of previous potentials of somatosensory evoked potential, as well as other neurophysiologic techniques, in the evaluation of lesions of the brain-stem.

Neurophysiological assessment of alpha pattern coma

Somatosensory evoked potentials, blink reflexes, and H wave reflexes, were recorded on several days from three patients with alpha pattern coma. Coma was secondary to cardiac arrest in two cases and to brainstem infarction in one. Results are compatible with damage to the brainstem reticular formation with sparing of thalamo-cortical circuits as the main physiopathological characteristic of alpha pattern coma. This condition should not be regarded as a discrete entity when establishing the prognosis of patients in coma, since they only differ from other patients in coma from the point view of the EEG record.