Subacute thyroiditis, also known as viral thyroiditis, DeQuervain’s thyroiditis, granulomatous thyroiditis or giant cell thyroiditis, was first reported by DeQuervain in 1904. The disease is clinically complex, can be misdiagnosed and underdiagnosed, and is prone to recurrence, leading to a decline in health, but most patients can be cured. The disease can be characterized by seasonal or viral epidemics with population onset.
I. Clinical manifestations.
It is mostly seen in middle-aged women. The onset of the disease is seasonal, with winter and spring being the most frequent periods for influenza. In a typical patient with “subarachnoiditis”, the entire course of the disease usually goes through three stages: “hyperthyroidism”, “hypothyroidism” and “recovery”. “The three phases are
1. Hyperthyroidism
The onset of hyperthyroidism is sudden, with fever, fear of cold, chills, fatigue and loss of appetite. The most characteristic manifestation is pain and pressure in the thyroid area, often radiating to the submandibular area, behind the ear or the neck, etc. The pain is aggravated when chewing and swallowing; the extent of thyroid lesions varies, starting with one lobe and later expanding or shifting to another lobe, or always limited to one lobe. The lesion is enlarged, hard and painful. When the lesion is extensive, it may be accompanied by the common manifestations of hyperthyroidism in addition to the general manifestations of infection.
2. Hypothyroidism
As the thyroid hormones stored in the thyroid follicles are gradually depleted, and the damaged thyroid tissue has not yet recovered its ability to synthesize and secrete thyroid hormones, the blood thyroid hormone level decreases, resulting in hypothyroidism.
3.Recovery period
The symptoms gradually improve and the goiter or nodules gradually disappear. If treatment is timely, most patients can recover completely, but very few can become permanently hypothyroid.
In mild or atypical cases, the thyroid gland is only slightly enlarged, the pain and pressure are mild, there is no fever, the systemic symptoms are mild, and there may not be clinical manifestations of hyperthyroidism or hypothyroidism. The duration of the disease varies, ranging from a few weeks to more than half a year, usually about 2 to 3 months, hence the name subacute thyroiditis. After remission of the disease, it may still recur.
II. Diagnosis.
Patients with fever and short-term enlargement of the thyroid gland with single or multiple nodules that are firm to touch and significantly painful to pressure can be clinically diagnosed initially as having this disease. Laboratory tests: early increased blood sedimentation, normal or slightly high blood white blood cell count; increased blood T3 and T4, decreased blood TSH; measured iodine uptake rate may drop to less than 5%-10%. This feature is important for the diagnosis of the disease. Blood thyroid immunoglobulin may also be elevated initially, and its return to normal is later than that of thyroid hormone. Ultrasonography is better for diagnosing and assessing whether it is active. Ultrasound images often show hypodense lesions at the site of pressure pain. Cytocentesis or tissue biopsy can confirm the presence of megakaryocytes.
III. Treatment.
Treatment of this disease consists of two main aspects: reduction of local pain symptoms and treatment for abnormal thyroid function.
1. Local pain relief treatment.
In mild cases, only non-steroidal anti-inflammatory drugs are needed; for severe patients with severe pain, high fever and ineffective treatment with non-steroidal anti-inflammatory drugs, glucocorticoid therapy can be given.
2.Treatment for different stages of thyroid function status.
Usually, non-specific drugs are used, such as oral propranolol tablets (Takeaway tablets). The “hyperthyroid phase” or “hypothyroid phase” of the disease is usually temporary. For the rare patients who develop permanent hypothyroidism, long-term replacement therapy is required.
Prognosis and prevention.
The disease is self-limiting, except for a very small number of patients (less than 10%) who eventually develop permanent hypothyroidism, the majority of patients can recover on their own, so the prognosis is good, but easy to relapse.
The majority of patients can recover on their own, so the prognosis is good, but it is easy to recur. Strengthen exercise, enhance physical fitness, improve the body’s immunity, avoid cold and flu, and vaccination against influenza can effectively prevent “subarachnoiditis”.