Thyroid  

 

Up

Breast

Thyroid

Gallbladder

Vascular

Painful Anus

Hernia

Approach to the Patient with a Thyroid Nodule

General

Goiter

Nodules of the thyroid are quite common in the United States.  It is estimated that between 4-10% of the population will have a palpable nodule at some point in their lives and the risk appears to be greater in women than in men.  Although nodular disease is common, malignant disease is rather uncommon (about 12,000 new cases per year or roughly 5% of nodules).

A goiter is simply an enlargement of the thyroid gland and may be diffuse or nodular.  The presence of a goiter does not necessarily suggest a diagnosis, as many diseases of the thyroid may be associated with a goiter.  For example, a goiter may be present in both hyper- and hypothyroidism.  Worldwide, the most common cause of goiter is iodine deficiency.  This has been largely eliminated in the United States by the supplementation of iodine in table salt.  The majority of goiters are benign and like their nodular counterparts, they are more common in women than in men (about 4:1). 

Before discussing the different diseases of the thyroid and the different causes for goiter or a thyroid nodule, it is important to review the anatomy of the thyroid as well as the physiology of thyroid hormone synthesis.  The anatomy of the thyroid will understate important surgical considerations and an understanding of thyroid hormone synthesis is important in appreciating how disease manifests itself when normal physiology goes awry.

Thyroid Anatomy     Thyroid Hormone Synthesis

Clinical Approach

In addition to a thorough history and physical for a patient presenting with complaints that arise suspicion of a thyroid disorder, and good examination of the thyroid gland is always in order.  The gland itself is usually easier to feel in a long slender neck than in a short, stocky person.  The following steps outline a typical thyroid exam.

bullet

The thyroid exam begins with inspection of the neck and trachea, looking for any deviation from midline.  Masses in the neck may push the trachea to one side or the other.  Inspection also involves looking for the thyroid gland and noting whether it is visible and symmetrical.  Having the patient tilt their head slightly back and using tangential lighting is often helpful.

bullet

Inspection is followed by palpation of the patients' neck.  From a position behind the patient, the fingers of both hands should be used to identify the cricoid cartilage and then moving downward two or three tracheal rings at a time, palpating for the isthmus.

bullet

After the isthmus, the fingers should be moved laterally from the midline to feel for the lobes of the thyroid.  Having the patient swallow may allow for glandular tissue to be felt rising and lowering under the examiner's fingers.

bullet

The size, symmetry, ad position of the lobes, as well as the presence of any nodules or goiter should be noted.  The normal gland (and isthmus) are often not palpable unless pathology exists.

Clinical Approach to the Thyroid

In addition, if the thyroid gland is enlarged, the lateral lobes can be auscultated with a stethoscope in order to detect bruits, which may be due to compression of thyroid vessels by a goiter or nodule.

Thyroid Disease

Thyroid disease can be categorized into benign conditions of the thyroid and malignant ones, and rarely there can be progression of one to the other.  The most commonly benign conditions affecting the thyroid gland are those which cause hyper- and hypothyroidism.  Malignancy of the thyroid is usually of the carcinoma variety. 

Factors which favor benign disease over malignancy include a family history of autoimmune disease (i.e. Hashimoto's) or benign thyroid nodule or goiter, the presence of hormonal dysfunction (hyper- or hypothyroidism), pain or tenderness associated with the nodule, and a soft, smooth, and mobile nodule.

Factors which favor malignant disease include age younger than 20 years or older than 70 years, male sex, history of neck irradiation, firm, hard, or immobile nodules, cervical lymphadenopathy, and associated dysphagia or dysphonia.

The three subcategories are presented below.

Hyperthyroidism     Hypothyroidism     Thyroid Cancer

Diagnostic Evaluation

A number of diagnostic modalities exist for the work-up of a thyroid nodule, goiter, or symptoms of thyroid disease.  They range from the most non-invasive (ultrasound) to the most invasive (biopsy).  Initial work-up typically involves blood tests, and the favored initial step in the work-up of a thyroid anomaly is a sensitive Thyroid Stimulating Hormone (TSH) assay.  A link to each of the commonly used investigations  is presented here.

Lab Tests     Ultrasound     Biopsy     Thyroid Scan

Treatment

The treatment of thyroid disorders depends on the type and extent of disease present.  For example, hypothyroidism and some forms of hyperthyroidism can be managed medically.  Other times, surgical intervention is necessary, particularly in the case of malignancy.  As this tutorial deals with the surgical aspect of dealing with thyroid disease, the surgical management will be presented comprehensively.  Medical management will be briefly mentioned under the specific disease entities where such therapy is warranted.

In addition, the staging system for thyroid malignancies will be outlined as staging is important in guiding treatment decisions (i.e. surgery vs. chemotherapy) and predicting prognosis.  Thyroid cancer is somewhat unique in that a number of different systems have been developed to determine staging. Most of them focus on weighing such factors as a patient's age, the size of a cancer at the time of diagnosis, whether the cancer has spread to invade other structures in the neck, and whether the cancer has metastasized to other sites in the body.   Fortunately, if caught early, thyroid cancer is very treatable and survival rates are close to 100%.

Staging     Surgical Treatment