Thyroid nodules are abnormal growth in the thyroid gland. They can be solid or fluid-filled lumps. The abnormal growth of fibroid tissues form nodules in the thyroid gland. The nodules may be benign or malignant. But, more than 96% of the nodules are noncarcinogenic. Description The Thyroid gland is situated at the base of the neck below the "Adam's apple". It is butterfly shaped and located in front of the neck. The two thyroid lobes on either side of the wind pipe is connected by a tissue called 'isthmus' which covers the wind pipe from the front side. It can develop on any part of the gland. Abnormal growth of the thyroid gland or excess growth of tissues leads to the formation of lumps. Mostly, these lumps are fluid filled and benign. When the nodule becomes large enough to compress the wind pipe, the person may feel difficulty in swallowing. Five percent of the nodules are cancerous or may lead to cancer. Causes The various causes are:

• Deficiency of iodine
• Thyroxin suppression due to physical agents
• Chronic thyroditis, which occurs due to hypothyroidism

Men are more likely to be affected by carcinogenic thyroid nodules. Continuous exposure of radiation to the head or neck causes this condition. Types There are seven types of nodules, which are listed below: Colloid nodules or Follicular adenoma They are the overgrowth of the thyroid gland, which are noncancerous. Only a single lobe is formed in such cases and it does not exceed beyond the thyroid gland. Hence, it is harmless. Thyroid cysts These nodules are of 1-1.5 cm in diameter and are filled with fluid. Sometimes they are malignant and also filled with solid substances. Inflammatory nodules They occur as a result of thyroiditis, i.e., chronic inflammation of the thyroid gland. One of its type is subacute thyroiditis, which causes severe pain in the neck region. Thyroid cancer They are malignant, very large, and hard lobes which causes discomfort in the neck region. Follicular adenoma They arise from follicular epithelium and are usually single and well-encapsulated lesions. They are also the most common type of nodules. Multinodular goiter It grows from an existing simple goiter. It contains multiple nodes and each node may be benign or malignant. Toxic multinodular goiter-Plummer's disease In this case, the thyroid gland secretes thyroxin without the influence of thyroid stimulating hormone (TSH). High levels of thyroxin in the blood results in a high metabolism rate. Symptoms The normal symptoms are:

• Pain in the neck region.
• Difficulty in swallowing.
• Sudden weight loss.
• Irregular heartbeat.
• Hoarseness i.e., difficulty in speaking.
• Enlargement of lymph nodes in the neck region.

Effects Though the nodule is benign, it creates critical complications. Some of them are:

• Heart problems which include rapid heart rate, irregular heartbeats, and the weakness of the heart muscles which leads to insufficient pumping of blood to various parts of the body.
• Osteoporosis, which includes weakened and brittle bones due to lack of sufficient amount of calcium in the body. This is due to the improper secretion of calcitonin by the thyroid gland.
• Thyrotoxis, which is a life-threatening condition.

Treatment The common treatment options are:

• Using radioactive iodine, which will reduce the size of the goiter, but, the radiation-induced therapy may result in side effects. Pregnant women should avoid this treatment.
• In cases where the nodule compresses the wind pipe, doctors prescribe a drug called Levothyroxine, which is used for immediate suppression of the production of thyroxin. This is called thyroid hormone suppression therapy.
• In alcohol ablation, ethanol is used to compress the nodules and reduces the excess secretion of thyroxin hormone.

When the nodules are cancerous, surgery is the only remedy. Disclaimer: This Buzzle article is for informative purposes only, and should not be used as a replacement for expert medical advice.