The main causes of convulsions are the following: i. Intracranial infections, such as viral meningitis, bacterial meningitis or tuberculous meningitis can cause secondary seizures, which manifest as limb twitching. Second, acute cerebrovascular disease, if there is lobar infarction or lobar hemorrhage, may also cause limb convulsions or persistent status epilepticus. Third, some patients with respiratory alkalosis during hyperventilation or hysterical seizures may also have limb twitching. Fourth, some patients with ischemic-hypoxic encephalopathy caused by sleeping pills or carbon monoxide poisoning may also cause cortical function impairment and limb convulsions. Fifth, if the patient has reduced blood calcium, hypocalcemia can also cause limb convulsions. Sixth, primary epilepsy.