RESUMO
Sudden unilateral hearing loss may result from etiologies affecting cochlea, eighth nerve, or more central auditory tracts. Two case studies are presented in which the measurement of otoacoustic emissions helped rule out outer hair cell cochlear pathology. In both cases, the final diagnosis was sudden unilateral hearing loss associated with multiple sclerosis (MS). For one case, the sudden hearing loss was the first clinically recognized presenting sign of MS.
Assuntos
Estimulação Acústica , Cóclea/fisiopatologia , Perda Auditiva/etiologia , Perda Auditiva/fisiopatologia , Esclerose Múltipla/complicações , Esclerose Múltipla/fisiopatologia , Adulto , Audiometria de Tons Puros , Potenciais Evocados Auditivos do Tronco Encefálico , Feminino , Lateralidade Funcional , Células Ciliadas Auditivas/fisiopatologia , Perda Auditiva/diagnóstico , Perda Auditiva Neurossensorial/diagnóstico , Perda Auditiva Neurossensorial/etiologia , Perda Auditiva Neurossensorial/fisiopatologia , Humanos , MasculinoRESUMO
Serial measurements were performed on the compound muscle action potential (CMAP) amplitude and the force generated by the rat lower hind limb flexors to investigate the time course of intramuscular injections of botulinum toxin type A (BOTOX). Thirty animals were used in this in vivo rat model. CMAP amplitude and muscle force were measured at predetermined intervals for 28 weeks. Compound muscle action potential amplitude and force declined markedly the first 5 to 7 days after injection of BOTOX but recovered in a near linear manner. The response magnitude and recovery rate were dose-dependent. Recovery of CMAP amplitude preceded recovery of muscle force. No clear evidence of a systemic effect on the untreated leg or a concentration effect was found. CMAP amplitude may be useful in determining optimal timing of repeat injections in treating neuromuscular disorders.
Assuntos
Potenciais de Ação/efeitos dos fármacos , Antidiscinéticos/farmacologia , Toxinas Botulínicas/farmacologia , Animais , Fenômenos Biomecânicos , Relação Dose-Resposta a Droga , Membro Posterior , Injeções Intramusculares , Contração Isométrica/efeitos dos fármacos , Masculino , Ratos , Ratos Sprague-Dawley , Estatísticas não ParamétricasRESUMO
Physiologic principles form the foundation upon which rational medical and surgical decisions are based. Over the years, a growing understanding of the physiology of the nose and sinuses has evolved, allowing us to better treat our patients with sinonasal disease. As clinicians, we are challenged to keep abreast not only of advances in therapeutic options but also of advances in physiology. In this manner, we may employ the new therapies with both skill and intelligence.
