Subacute thyroiditis is mostly caused by viral infection and is characterized by fever, painful and enlarged thyroid gland with systemic inflammatory reaction. In mild cases, anti-inflammatory and analgesic treatment can be given to reduce the inflammatory response and relieve pain. Glucocorticoids can rapidly relieve pain, reduce thyrotoxic symptoms and shorten the course of the disease. Let’s start with the characteristics of subacute thyroiditis: hypothermia; sudden onset of neck (thyroid pain): sudden, wandering and radioactive; sudden enlargement of the thyroid gland with significant pressure pain; significant increase in blood sedimentation; thyroid ultrasound: enlarged thyroid gland with hypoechoic nodules; increased or normal T3T4, significant decrease in iodine uptake by the thyroid gland, separation phenomenon; glucocorticoid therapy: significant effect, dramatic effect with Immediate effect, fever and pain are relieved immediately after taking the medication, generally within 2 to 3 days thyroid pain disappears and the thyroid gland shrinks. The following is a detailed description of subacute thyroiditis (Subacutethyroiditis) Subacute thyroiditis is the abbreviation for subacute thyroiditis, which is mostly seen in adults between 30 and 50 years of age, with a higher incidence in women than in men. The disease is mostly caused by viral infection of the thyroid gland and is characterized by transient painful and destructive thyroid tissue damage with a systemic inflammatory response. Clinical manifestations: The onset of the disease often occurs 1-3 weeks after viral infection, with varying forms and degrees of disease onset. 1, upper respiratory tract infection prodromal symptoms: muscle pain, fatigue, lethargy, sore throat, etc., body temperature increases to varying degrees, peaking 3-4 days after the onset of the disease. It may be accompanied by enlarged lymph nodes in the neck. 2. Characteristic pain in the thyroid area: occurs gradually or suddenly, with varying degrees. It often radiates to the ipsilateral ear, throat, mandibular angle, chin, occiput and chest and back. A small number of patients have hoarseness and difficulty swallowing. 3. Enlarged thyroid gland: diffuse or asymmetric mild or moderate enlargement, mostly with nodules, hard texture, obvious tenderness, no tremor or murmur. Goiter often involves one lobe first and then extends to the other lobe. 4. Clinical manifestations associated with changes in thyroid function: (1) thyrotoxic phase: about 50%-75% of patients have weight loss, fear of heat, tachycardia, etc. at the beginning of the disease, which lasts about 3-8 weeks; (2) hypothyroid phase: about 25% of patients enter the hypothyroid phase before the synthesis of thyroid hormones is restored, with edema, fear of cold, constipation and other symptoms; (3) hypothyroid phase: about 25% of patients enter the hypofunction phase before the synthesis of thyroid hormones is restored. (3) thyroid function recovery stage: most patients recover normal function for a short period of time (weeks to months), and only a few become permanently hypothyroid. The whole course of the disease lasts about 6-12 months. Some cases have recurrent exacerbations that last from a few months to 2 years. About 2-4% of cases are recurrent, and very few are recurrent. Laboratory tests 1, erythrocyte sedimentation rate (ESR): early in the course of the disease increased, > 50mm/h is favorable support for the disease, ESR does not increase can not exclude the disease. 2. Thyrotoxic phase: A bidirectional separation phenomenon presenting elevated serum T4 and T3 concentrations and reduced iodine uptake by the thyroid gland (often less than 2%). As the destruction of thyroid follicular epithelial cells worsens, transient hypothyroidism occurs, T4 and T3 concentrations decrease, and thyrotropin (TSH) levels increase. When the inflammation subsides and the thyroid follicular epithelium is restored, thyroid hormone levels and thyroid iodine uptake rate gradually return to normal. FNAC is not a routine test for the diagnosis of this disease. 4. thyroid nuclear scan: no uptake or low uptake of the thyroid gland in the early stage is helpful for diagnosis. The diagnosis is based on acute onset, fever and other systemic symptoms, painful, enlarged and hard thyroid gland, combined with a significantly increased ESR and a bidirectional separation of elevated serum thyroid hormone concentration and reduced iodine uptake by the thyroid gland. Differential diagnosis 1. Upper respiratory tract infection: the presence of fever, anterior neck pain and sore throat is easily misdiagnosed as epiglottitis or pharyngitis and treated with antibiotics. Therefore, patients with fever with cervicopharyngeal pain should consider the possibility of subxiphoiditis and undergo thyroid-related tests. 2. Hemorrhagic nodular goiter: sudden bleeding may be accompanied by thyroid pain and fluctuating sensation at the site of bleeding; however, there are no systemic symptoms and ESR is not elevated; thyroid ultrasonography is helpful for diagnosis. 3. Hashimoto’s thyroiditis: a few may have thyroid pain and tenderness, ESR may be mildly elevated during the active phase, and transient thyrotoxicosis and reduced iodine uptake may occur; however, there are no systemic symptoms, and serum TgAb and TPOAb titers are elevated. 4. Painless thyroiditis: This disease is a variant of Hashimoto’s thyroiditis, a type of autoimmune thyroiditis. There is goiter and the clinical presentation goes through 3 stages of thyrotoxicosis, hypothyroidism and recovery of thyroid function, similar to subacute thyroiditis. Differentiation point: this disease has no systemic symptoms, no thyroid pain, ESR is not increased, FNAC examination is feasible to differentiate if necessary, focal lymphocytic infiltration is seen in this disease. 5, hyperthyroidism (hyperthyroidism): iodine-induced hyperthyroidism or hyperthyroidism in which the rate of iodine uptake is suppressed by exogenous iodide, with elevated serum T4 and T3, but reduced 131I uptake, needs to be differentiated from subacute thyroiditis. The distinction can be made based on the duration of the disease, systemic symptoms, thyroid pain, T3/T4 ratio in hyperthyroidism and ESR. Treatment Subacute thyroiditis is a self-limiting disease that eventually resolves on its own. In mild cases, anti-inflammatory and analgesic agents such as acetylsalicylic acid, indomethacin and cyclooxygenase-2 inhibitors can be given to reduce the inflammatory response and relieve pain. Glucocorticoids can rapidly relieve pain, reduce the symptoms of thyrotoxicosis and shorten the course of the disease. The 2008 Chinese guidelines for the management of subacute thyroiditis recommend initial prednisone 20-40 mg/day, maintained for 1-2 weeks, and slowly reduced for a total duration of not less than 6-8 weeks. For the indication of discontinuation of hormone therapy, it is recommended that glucocorticoids should be discontinued only after the iodine uptake rate returns to normal or the blood sedimentation returns to normal. Excessive dose reduction and premature discontinuation may lead to recurrence of the disease and should be avoided. In case of recurrence during discontinuation or dose reduction, glucocorticoids can still be used. Of course, hormones have their own adverse effects and contraindications. Therefore, it is necessary to prevent their side effects during application, such as using antacid preparations to protect the stomach and adding calcium tablets and vitamin D to prevent osteoporosis. If you are allergic to glucocorticoids, have a history of severe psychiatric illness, epilepsy, active peptic ulcer, post-operative gastrointestinal anastomosis, fracture, trauma repair period, herpes simplex or ulcerative keratoconjunctivitis, severe hypertension, severe diabetes, uncontrolled infection (such as chickenpox, fungal, tuberculosis infection), early pregnancy and puerperium, common psoriasis, etc., use with caution or prohibit while actively treating the original disease Hormones. Viral infection is the main cause of subacute thyroiditis, and it is still clinically controversial whether to use antiviral drugs for treatment. The entire course of subacute thyroiditis treatment is about 6-12 months, and usually after 6-12 months, thyroid function returns to normal in 95% of patients, hypothyroidism occurs in 5% of patients, and recurrence can occur in 2% of patients. After treatment of subacute thyroiditis, those with hypothyroidism should take additional thyroid tablets to eliminate symptoms as appropriate.