RESUMO
BACKGROUND: Thirty-nine percent of permanent altitude dwellers in the Andes experience acral paresthesias. METHODS: Clinical examinations, sural nerve biopsies, and electrodiagnostic studies on peripheral nerves were performed on 15 men. Ten Cerro de Pasco (CP) natives living at 4,338 meters were biopsied. Three of these subjects had no burning feet/burning hands (BF/BH); three had BF/BH; and four had chronic mountain sickness (CMS), a maladaptation syndrome resulting from living in the Andes, all with BF/BH. Three patients with CMS were biopsied in Lima within hours after leaving CP. Two normal Lima natives were biopsied in Lima. Symptom scores for BF/BH and CMS score ratings were used. The nerves were assayed for Na+, K+ adenosine triphosphatase (ATPase), cytochrome oxidase (CO), substance P (SP), and endothelin (ET). RESULTS: Low ATPase was inversely related to symptom scores and CMS scores (p < 0.001). Patients with CMS biopsied in normoxia (Lima) had ATPase levels similar to those of controls. Nerve motor conduction velocities and sensory action potentials were normal. CO was inversely related to age (p < 0.03) and no relation of SP to any variable was found. ET levels were lower in sea level natives (p = 0.04). CONCLUSIONS: Acral paresthesias are associated with low ATPase in peripheral nerves. Lower ET levels of sea level natives likely reflect lowered release from vasa nervorum.
Assuntos
Altitude , Parestesia/fisiopatologia , Adulto , Doença da Altitude/enzimologia , Doença da Altitude/metabolismo , Biópsia , Complexo IV da Cadeia de Transporte de Elétrons/metabolismo , Endotelinas/metabolismo , Humanos , Masculino , Condução Nervosa/fisiologia , Parestesia/enzimologia , Parestesia/metabolismo , Peru , ATPase Trocadora de Sódio-Potássio/metabolismo , Substância P/metabolismo , Nervo Sural/química , Nervo Sural/metabolismo , Nervo Sural/fisiopatologiaRESUMO
An epidemic of bilateral optic neuropathy and painful sensory neuropathy occurred in Cuba in 1991-1993. Over 45,000 individuals were stated to have been affected. We report a clinical study on 25 patients seen in Cuba in 1993-1994. Affected patients showed either bilateral optic neuropathy with caecocentral scotomata or a distal predominantly sensory neuropathy sometimes associated with deafness, or a combination of both optic and peripheral sensory neuropathy. The nature of the epidemic is discussed. The clinical features in patients with confirmed neurological deficits were consistent with a diagnosis of Strachan's syndrome, probably related to nutritional deficiency. Other patients with similar symptoms showed no evidence either of optic or peripheral neuropathy and were considered to represent disease mimicry on a psychoneurotic basis.