Some of the causes of limb weakness in middle-aged and elderly people are as follows: 1. Brain stem infarction, brain stem infarction will lead to acute limb weakness, which may be accompanied by facial paralysis, consciousness disorder and cone beam sign. These patients mostly have hypertension, diabetes mellitus and other underlying diseases, which are easier to recognize.2. Hypokalemia, hypokalemia is also a common cause of acute weakness of limbs in middle-aged and elderly people. Most of these patients have a history of hyperthyroidism, which can cause recurrent weakness.3. Acute Guillain-Barre Syndrome, which is a demyelinating lesion, is more common in the middle-aged and elderly population. Patients have a history of diarrhea and colds before the onset of the disease.4, spinal cord lesions, such as spinal cord trauma, degeneration, tumors and other spinal cord diseases, can cause middle-aged and elderly people to have weakness in the limbs, and there are paraplegic planes and sensory planes.5, fever, infectious diseases, such as pneumonia, colds and so on, can cause middle-aged and elderly people to have weakness in the limbs, body aches and pains.