Special Thyroid Gland Disorders: Thyroiditis, Solitary thyroid Nodule And Tumours Of The Thyroid

Acute suppurative thyroiditis may be caused by bacteria. It is rare.

Subacute Nonsuppurative thyroiditis (SAT, or De Quervain’s syndrome): This condition probably results from viral infection or autoimmune disorders. Females are affected. The thyroid is enlarged, painful and tender. Sometimes, signs of mild hyperthyroidism may be evident. Average course of the illness is 2-4 months. The condition responds promptly to corticosteroids.

Chronic Lymphocytic thyroiditis (Hashimoto’s disease- Autoimmune thyroiditis): There is a close relation between Grave’s disease and Hashimoto’s disease which is an autoimmune disorder. The peak incidence occurs in the fourth and fifth decades of life. Females are affected more commonly than males. The thyroid is infiltrated with lymphocytes. Large hyperplastic lymph follicles with germinal centers are present. The follicles contain very little colloid. Varying degrees of fibrosis may be present. The thyroid is diffusely enlarged, lobulated, firm or hard in consistency and painless. Although rarely toxic, diffuse goiter may coexist with Hashimoto’s disease (Hashitoxicosis). More commonly, it is associated with hypothyroidism. Most characteristic laboratory feature is the presence of high titers of circulating antibodies. Lower titers of the antibodies may be seen in relatives of the patient. Other autoimmune diseases like Sjogren’s syndrome, pernicious anemia, Grave’s disease, myasthenia gravis and rheumatoid arthritis may be associated. Erythrocyte sedimentation rate is markedly elevated and serum gammaglobulin is high.

Course: The condition may persist as such for many years. As a sequel hypothyroidism may develop in many cases.

Treatment: Present day therapy is to give long term suppressive medication with T₄ in a dose of 0.2 to 0.3mg daily. This leads to rapid resolution of the goiter.

This is a common clinical problem which demands clinical examination and investigation for diagnosis.

1. Rapidly enlarging tumour suggest either hemorrhage into the nodule or malignancy.
2. Consistency- hard solitary nodule is suggestive of malignancy.
3. T3 and T4 estimation-malignant nodules are functionally less active than benign nodules.
4. Scintiscan helps in assessing the function of the nodule. Cold and normally functioning nodules show a relatively high incidence of malignancy. As a general rule, hyperfunctioning nodules do not become malignant.
5. Ultrasonography is an easily available noninvasive method to differentiate solid from cystic lesions. Cold solid nodules show a high rate of malignancy.
6. In order to detect whether a hyper-functioning nodule is autonomous or not, scinti-scanning is repeated after a course of oral T3 for 5 days. In the case of autonomous nodules, the iodine uptake is not suppressed.

Treatment: The management of a solitary nodule is still a matter of controversy. Early surgery is recommended for solitary cold nodules and hard rapidly growing nodules. Lymph node enlargement of recent onset calls for early surgery. In the other cases, the patient is followed up. For normally functioning and non-autonomous nodules, a course of thyroid hormone (0.3mg/day) is given. Thyroid hormone is of no use in the treatment of autonomous hyperfunctioning nodules. Such nodules can be irradiated with I¹³¹ given after a course of T³ for 5 days. T₃ suppresses iodine uptake by the normal tissue and thus I¹³¹ gets concentrated only in the autonomous nodule.

Thyroid may be the seat of benign or malignant neoplasms. Most of the malignant tumours are primary, rarely metastases from the kidneys, breasts and lungs may occur. Benign tumours are adenomas. Carcinomas are rare. They may be differentiated or undifferentiated. Irradiation to the tonsils, thymus, lungs or cervical lymph nodes during childhood may predispose to carcinoma of thyroid after a latent period of 10-20 years. Rarely thyroid may be the seat of lymphoma or sarcoma.

Medullary carcinoma of thyroid: Around 10-15% of malignant lesions of the thyroid are medullary carcinomas. The disease may be familial and relatives of patients may show elevation of serum calcitonin levels, if they are harbouring latent tumours. Medullary carcinoma arises from ‘C’ cells or parafollicular cells. Metastasis is common. Elevation of serum calcitonin level is diagnostic in the presence of a palpable thyroid nodule.

Medullary carcinoma may coexist with other endocrine tumours (multiple endocrine adenomatosis) such as bilateral pheochromocytoma and hyperparathyroidism. Since the tumour secretes prostaglandins and 5-hydroxy tryptamine, flushing and diarrhea are prominent features. Treatment consists of surgical removal of the carcinoma. Medullary carcinoma does not respond to I¹³¹ therapy.

Thyroiditis, solitary thyroid Nodule and tumours of the thyroid either do not frequently occur or occur due to rare causes and for this reason are special thyroid gland disorders. Their recent occurrences give concern to health workers and the world of medicine and hence are becoming of huge clinical relevance in our battle to combat illnesses.