Common diseases of limb weakness: Grinbarr’s syndrome, myasthenia gravis, hypokalemic paralysis, myelitis, myotonic dystrophy, polymyositis, cervical spinal stenosis, mitochondrial myopathy and other less common diseases. There are acute and chronic forms of Guillain-Barre syndrome. Acute Guillain-Barre syndrome is often preceded by symptoms of prodromal viral infections such as fever, diarrhea due to viral enteritis, symmetric limb flaccidity, peripheral (glove and glove-like) sensory impairment, head and facial nerve damage, sweating, urinary and fecal dysfunction, and other autonomic impairments. -The phenomenon of cell separation is obvious in 2~3 weeks after the onset of the disease. Acute Greenbrier syndrome progresses faster, with an exacerbation period of 7-14 days, after which the disease stabilizes and starts to recover significantly in about 30 days. Features of myasthenia gravis: morbid fatigue. Cannot tolerate general fatigue, severe condition, rapid relief after rest, light morning and heavy curtain, no sensory impairment, no cone bundle sign; EMG low frequency repetitive electrical stimulation with wave amplitude reduction performance, no slowdown of nerve conduction velocity. The diagnosis can be confirmed by a positive result of fatigue test and drug tests such as neostigmine test and tensilon test. Mostly combined with thymoma and thymic hyperplasia, CT examination of the lungs and mediastinum should be performed. Hypokalemic paralysis is commonly induced by cold, excessive fatigue, after rest, after a full meal, vomiting, diarrhea, some may be drug-induced, such as the application of corticosteroids, etc., common tetraplegia, early limb proximal obvious, can be extended to the distal, often no sensory impairment, cranial nerve is rarely damaged; check the electrocardiogram can be seen obvious u wave, blood test blood potassium below normal can confirm the diagnosis, oral potassium supplementation can be corrected in a short period of time, low potassium, improve the symptoms. Oral potassium supplementation can correct hypokalemia and improve the symptoms in a short period of time, but the effect of potassium supplementation in chronic hypokalemic paralysis is not obvious. Many patients can be combined with increased creatine kinase, some classes up to 1000 to 2000. Myelitis: more fever, bilateral lower limbs or quadriplegia symmetrical paralysis, sensory impairment, with sensory impairment plane, accompanied by urinary and fecal retention, early spinal shock phenomenon, that is, the limbs show soft palsy, hypotonia soft, 15-20 days later transformed into rigid palsy, that is, increased muscle tone hard, positive bilateral pathological signs, spinal cord MRI shows obvious signs of spinal cord damage. Myotonic dystrophy: It is a hereditary disease with muscle atrophy and weakness, which can be divided into several types. There may be an increase in creatine kinase. General treatment is ineffective and insulin glucose therapy may improve the symptoms. EMG nerve conduction velocity is not altered, and there is no clear change in low frequency repetitive electrical stimulation. Blood potassium is normal. Polymyositis: there may be myalgia and muscle weakness, no numbness, squeezing pain in muscles, no change in EMG nerve conduction velocity, no clear change in low frequency repetitive electrical stimulation, normal blood potassium. The muscle enzyme spectrum is significantly increased, the application of corticosteroid treatment can quickly relieve the symptoms, viral myositis improves faster. Mitochondrial myopathy: for energy even metabolic abnormalities disease, there is obvious fatigue can not be tolerated, commonly known as no inch strength or say four or two strength are not, than the severe muscle weakness is also obvious intolerance of fatigue, there can be muscle enzyme spectrum increased, lactate metabolism abnormal, muscle biopsy can confirm the diagnosis, but sometimes more difficult. Mitochondrial myoencephalopathy may have seizures and mental retardation. Brain MRI may show scattered abnormal signals in the gray matter of the cortex. Cervical spine injury may have a history of trauma or progressive discomfort, which can be clarified by examination of cervical MRI. Abnormal thyroid function may also present with weakness or poor force in the extremities, which may manifest as muscle weakness or hypokalemic paralysis, etc. Relevant examinations should be performed. If a similar situation occurs, you should go to the neurology department of a hospital with the condition to have a systematic examination and related tests to clarify the diagnosis and choose an effective treatment plan. Only if the diagnosis is clear can the treatment be targeted and the symptoms can be effectively improved to achieve the purpose of cure. But some are not incurable.