If hyperthyroidism is not treated in time, it is easy to cause various complications. Complications caused by hyperthyroidism mainly include hyperthyroidism heart disease, hyperthyroidism ophthalmopathy, hyperthyroidism myopathy, hyperthyroidism periodic paralysis, etc. In severe cases, it can lead to hyperthyroidism crisis, which can be life-threatening if not resuscitated. The seriousness of the disease can lead to hyperthyroidism crisis, often life-threatening when the rescue is not enough. 1, hyperthyroidism heart disease hyperthyroidism heart disease refers to hyperthyroidism patients appear arrhythmia, or heart enlargement, or heart failure, with a long history of failure to good control of people and the elderly hyperthyroidism is common. In addition to the typical clinical manifestations of hyperthyroidism, this disease is often characterized by palpitations, dyspnea, precordial pain, premature beats or paroxysmal atrial fibrillation, and even persistent atrial fibrillation. Treatment is mainly to control the hyperthyroidism, if there is heart failure, arrhythmia can be symptomatic treatment, hyperthyroidism control can generally be completely normal. 2, hyperthyroidism protruding eyes Hyperthyroidism protruding eyes can occur at the same time with hyperthyroidism, can also appear in hyperthyroidism before or after the improvement. The severity of ophthalmopathy and hyperthyroidism are not parallel in most cases, and some patients with hyperthyroidism are not obvious, but their ophthalmopathy is very serious. It can be categorized as non-infiltrative or infiltrative proptosis. The former manifests as widening of the eyelid, eyelid retraction, gaze, reduced blinking and mild proptosis; the latter may manifest as excessive tearing, photophobia, ocular pain, stinging, foreign body sensation, inability to close the eyes, conjunctival edema and congestion, orbital edema, limited eye movement, double vision, visual field defect, visual acuity loss, and even blindness. No special treatment is needed for benign proptosis, only hyperthyroidism can be treated. In infiltrative cases, adrenal glucocorticosteroids can be used along with antithyroid medications, and in a few cases, ocular radiation therapy or ocular surgery is needed. Regardless of which treatment is used, it is very important to take good care of the eyes during the treatment period. Eye care includes elevating the bed during sleep, wearing sunglasses when going out in order to avoid light and dust, taking eye drops, applying eye ointment, or wearing eye masks. 3, chronic hyperthyroidism myopathy This disease is more common, can occur in 80% of patients with hyperthyroidism, slow onset. Patients often complain of difficulties in squatting, standing up, going upstairs and combing their hair. Treatment is mainly for hyperthyroidism, and there is no special treatment except symptomatic treatment. Generally, it can be alleviated with the alleviation of hyperthyroidism. 4.Hyperthyroidism combined with periodic paralysis This disease mostly occurs in male young adults, seizures are often accompanied by low blood potassium, high-carbohydrate diet can be induced by this disease, often in the middle of the night seizures. The main manifestation is episodic flaccid paralysis of the limbs and trunk, with paralysis of the lower limbs being more common. In severe cases, there may be paralysis of the respiratory muscles, accompanied by loss of tendon reflexes, and the episodes may last for several hours to days, with a great deal of variability in the frequency of the episodes. The frequency of seizures varies widely from one individual to another. The disease may be related to the transfer of potassium from cells to cells. The main treatment is potassium supplementation. For patients with no previous history of hyperthyroidism, if paralysis caused by low potassium occurs, it is necessary to clarify whether hyperthyroidism exists. 5, hyperthyroidism crisis, hyperthyroidism crisis is common in the hyperthyroidism of long-term uncontrolled people, to the elderly is more common. It is often associated with infection, mental trauma, surgery, childbirth, overwork, and sudden drug withdrawal. The main manifestations are high or ultra-high fever (often higher than 40℃), rapid pulse rate (often higher than 160 times/min), irritability, nausea, vomiting, diarrhea, sweating, excitement and trembling, and even hazy consciousness and coma. This disease can be life-threatening and has a high mortality rate, so prevention should be the mainstay, and once detected, it should be actively treated. The principle of treatment is to inhibit the production and secretion of thyroid hormone with medication, reduce the response of the brain and surrounding tissues to thyroid hormone and general symptomatic treatment. In addition, the complications of hyperthyroidism include acute hyperthyroid myopathy, hyperthyroid hypertension, hyperthyroid psychosis, anterior tibial mucous edema and so on, all of which are rare, and if they occur, they need to go to the hospital in time.