中国医科大学神经病学英文课件 motor neuron disease.pptVIP

Motor neuron disease ,MND zheng dongming Background The incidence of the disease is one to two per 100 000. The disease predominantly affects middle aged and elderly people.younger people are occasionally affected. The disease is sporadic in 90% of cases, but about 10% are familial, usually with an autosomal dominant mode of inheritance. The disease causes progressive injury and cell death of lower motor neurone groups in the spinal cord and brain stem and usually also of upper motor neurones in the motor cortex. Those affected typically develop a combination of upper and lower motor neurone signs, with progressive muscle weakness and wasting usually accompanied by pathologically brisk reflexes, eventually involving the limb and bulbar muscles Etiology and pathogenesis Genetics : More than 60 different mutations, mainly point mutations, have been described the most important findings has been that mutations in the gene on chromosome 21 encoding the enzyme Cu/Zn superoxide dismutase (SOD1) underlie 20% of familial cases of motor neurone disease and 2% of all cases. Etiology and pathogenesis Excitotoxicity: Glutamate is the main excitatory neurotransmitter in the human nervous system. Excessive stimulation of neuronal glutamate receptors can damage and kill these cells. Immune factors viral infection 1.Aamyotrophic lateral sclerosis ALS Motor neuron of Anterior horn,brain stem,pyramidal tract. 40 years old,malefemal weakness and wasting, The interossei and the muscles of the thenar eminence are affected early. spread proximally to involve the muscles of the shoulder girdle and the trunk. 1.Amyotrophic lateral sclerosis ALS Fasciculation is a prominent sign. Upper motor neuron signs in the lower limbs . There is usually a spastic weakness of the legs with increased tendon jerks and extensor plantar responses. Upper motor neuron signs may also ext