Subacute Thyroiditis



Subacute thyroiditis refers to inflammation of the thyroid gland which devlops over a period of weeks.



Symptoms occur in two phases:



Symptoms of hyperthyroidism:


1. Pain in the thyroid area, at times pain also radiates to the ear.


2. Restlessness


3. Palpitations


4. Insomnia


5. Excessive perspiration


6. Intolerance to heat


7. Excessive weight loss




A few weeks later, these symptoms subside on their own and symptoms of hypothyroidism develop, which include:


1. Fatigue, sluggishness


2. Weight gain


3. Intolerance to cold


4. Depressed mood


5. Excessive weight gain



Cause of Subacute Thyroiditis



The cause of subacute thyroiditis is an inflammation of the thyroid gland which destroys the architecture of the thyroid gland.


Normally the thyroid gland stores a large amount of thyroid hormones to be released in small quantities over a period of time.


With the destruction of the gland caused by the storm of the subacute thyroiditis, the large quantities of the stored thyroid hormones gets released into the blood circulation. This causes the phase of hyperthyroidism.


The thyroid hormones remain in circulation for a few weeks (6-12 weeks) and so does the phase of hyperthyroidism.


After the storm clears up, the thyroid gland start to repair itself but it takes a while.


During this period, there is shortage of thyroid hormones, which gives rise to the phase of hypothyroidism.


This phase typically last a few weeks (6-12 weeks) and so does the phase of hypothyroidism.


Eventually, in most cases the thyroid gland restores back to normal, although some patients may become hypothyroid permanently.




Diagnosis of Subacute Thyroiditis



Diagnosis of subacute thyroiditis is a tricky one. Patients usually consult their family physician who often do not think about the possibility of subacute thyroiditis.


Patient get placed on a variety of medicines to control their symptoms which do not get better and they feel quite frustrated.


It takes an endocrinologist to diagnose subacute thyroiditis.



Tests include:


1. TSH, Free T4, FreeT3


2. Thyroid Antibodies


3. A thyroid scan using I-123


The I-123 thyroid scan is the most useful tool in deciding whether hyperthyroidism is due to subacute thyroiditis or Graves' disease.


However, the I-123 thyroid scan should not be done if a patient is pregnant or breast-feeding.




Treatment of Subacute Thyroiditis



In the majority of cases, subacute thyroiditis is a self-limiting disease. Therefore, no specific treatment is required. However, close monitoring is essential.


Symptoms of hyperthyroidism can be managed with a BetaBlocker such as atenolol or propranolol.


If pain in the thyroid area is intolerable, a short course of oral steroids such as Prednisone is quite helpful.


Symptoms of hypothyroidism may requires a short course of thyroid hormone replacement with T4 and T3.


Patient education and close monitoring of the thyroid functions are the most important component of the treatment.




This article was written by Sarfraz Zaidi, MD, FACE. Dr. Zaidi specializes in Diabetes, photoEndocrinology and Metabolism.



Dr. Zaidi is a former assistant Clinical Professor of Medicine at UCLA and Director of the Jamila Diabetes and Endocrine Medical Center in Thousand Oaks, California.



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