Werner & Ingbar's The Thyroid: A Fundamental & Clinical Text, 9th Edition

18.Physical Examination of the Thyroid Gland

James V. Hennessey

Traditionally, clinicians have correlated characteristic physical findings with historical clues to synthesize a diagnosis. Advancements in diagnostic techniques seem to have relegated physical examination of the thyroid to a less important role, leading some to conclude that examination of the thyroid may be a lost or unlearned art for many physicians (1). Consensus guidelines, however, continue to emphasize the importance of thyroid physical findings detected during clinical assessment (2,3). Techniques of examination and the physical findings described are taught as expert opinion and, in some cases, as a consensus of broad agreement.

Evaluation of the patient with potential thyroid disease begins with the interview. Hoarseness of the patient's voice may be a sign of recurrent laryngeal nerve compression, associated with large benign goiters (4) or malignant thyroid lesions, and necessitate laryngoscope confirmation (5). Significant thyroidal displacement of the trachea may cause an inspiratory stridor requiring emergent intervention.

Inspection of the neck begins with a survey to assess for scars, asymmetry, or masses. The survey is likely best accomplished from a vantage point in front and off to the side of the patient (4,5). A scar indicating past thyroid surgery points to potential thyroid disease in patients with nonspecific symptoms (5,6,7). Erythema overlying a tender swelling is seen in acute suppurative thyroiditis (4), an infected thyroglossal duct (8), and branchial cleft cysts (9).

The patient extends the neck to lift the thyroid and stretch the overlying skin. The head is tilted back a moderate degree to relax the sternocleidomastoid (SCM) muscles (5,10). The examiner identifies the thyroid and cricoid cartilages (Fig. 1A). Light from the side and slightly above enhances a shadowed border of these features at rest and during swallowing. Normally, the extended neck from the cricoid to the sternal notch will form a straight line. Viewed from the side, anterior bowing suggests the presence of a goiter (11,12,13).

FIGURE 18.1. A: Landmarks in the physical exam of the thyroid. B: Examination of the thyroid facing the patient, with the fingers of the right hand on the left lobe of the thyroid. C: Examination of the thyroid from behind the patient.Here, fingers of each hand palpate both thyroid lobes simultaneously. D: Examination of the neck for the presence of lymphadenopathy along the left sternocleidomastoid muscle.

Facing the patient, the trachea is inspected for deviation from midline. As the thyroid is fixed to the pretracheal fascia, the gland will rise with the trachea upon swallowing (1,5). During the normal swallowing act, both the thyroid and the trachea move upward some 1.5 to 3.5 cm and hesitate momentarily before returning to their resting position (14). A neck mass is likely not thyroidal if it does not move upon swallowing, does not hesitate along with the thyroid and trachea before returning to its original position, or is noted to move in an asynchronous manner in relation to the thyroid and trachea (11). Thyroid movement upon swallowing may be lost if a goiter is so large that it occupies extensive space in the neck, or if an invasive carcinoma, lymphoma, or Riedel's thyroiditis has caused fixation to the surrounding tissues (5,15).

Pseudogoiter refers to apparent thyroidal enlargement when no true goiter is present. Thin patients may appear to have a prominent-appearing thyroid, especially when the gland is located higher in the neck, overlying the thyroid cartilage. These glands are actually of normal size by palpation (16). The presence of other cervical masses such as adipose tissue—either diffusely distributed or as a lipoma (17)—cervical lymphadenopathy, branchial cleft cysts, or pharyngeal diverticula (11) may simulate the appearance of a goiter. Finally, the illusion of a goiter may be seen when patients with long, curved necks have exaggerated cervical spine lordosis (Modigliani syndrome; named for the painter whose subjects demonstrated similar neck anatomy) (18).

A visible midline mass superior to the isthmus may represent a thyroglossal duct cyst, which may present at any age as a tense, nontender, round mass at or just below the level of the hyoid bone, and accounts for three quarters of congenital neck masses (19). These structures, which may, rarely, harbor a papillary thyroid cancer (19), can undergo acute hemorrhage or become infected and tender. Despite their cystic nature, these cysts usually do not transilluminate (11). Unique to the thyroglossal duct cyst is movement upward as the tongue is extended. Cystic structures located laterally, near the anterior border of the SCM muscles at the level of the hyoid bone (junction of upper one third and lower two thirds of the SCM muscles) likely represent branchial cleft cysts and account for one quarter of the congenital neck masses (9). Branchial cleft cysts are usually unilateral, slow growing, often fluctuant masses that occur during the second and third decades of life and remain motionless during swallowing. Occasionally these cysts may become abscessed and eventually rupture (9).

 

Occlusion of the thoracic outlet by a large retrosternal goiter may occur when the arms are extended over the head. The “Pemberton's sign” results in the obstruction of venous return from the head and neck region, results in visible venous distension over the neck, plethoric changes in the color of the facial skin, and may be associated with difficulty breathing and/or rarely syncope (5,7).

There is no consensus as to the optimal position of the examiner to the patient when palpating the thyroid (1,5,7,20). Most agree that with practice and patience the normal thyroid gland can be readily palpated, and the ability to feel thyroid tissue does not automatically signify enlargement of the thyroid (1,3,5,10). The patient may be seated with the head tilted slightly posteriorly but avoiding extreme stretching to relieve tension on the overlying tissues. Bed-bound patients may be examined by the positioning of a pillow across the scapulae, allowing a backward head tilt and easier palpation of the thyroid in the supine position (1).

The author of this section in the previous edition favors thyroid palpation while facing the patient (1). The examiner identifies the cricoid cartilage and seeks the isthmus of the thyroid directly below this landmark (Fig. 1A). The presence of kyphosis and emphysema in the elderly may result in the cricoid being displaced behind the sternum, making thyroid palpation in such individuals extremely difficult (1). Palpation of the isthmus with the thumb is accomplished by moving the thumb over the isthmus and with the thumb stationary during swallowing. As outlined in the previous edition, the examiner approaches the patient from the right to examine the left lobe and from the left to examine the right lobe. From the right, the left lobe is palpated with two or three fingers of the right hand lateral to the trachea and medial to the SCM muscles, with the thumb placed right of the trachea (1) (Fig. 1B). Palpation starts above the expected location of the thyroid and moves downward in a circular, rubbing motion, applying gentle (but adequate) pressure as the lobe is examined. The fingers are kept stationary at various levels of interest, and the patient swallows, sliding the thyroid beneath the fingers. An alternative to examining from alternate sides of the patient is accomplished, i.e., from the right by using the right thumb to palpate the right lobe and the fingers to examine the left lobe, as described earlier.

Others recommend palpation with the examiner positioned behind the seated or standing patient (4,6,10,20). The examiner places the fingers of both hands on the patient's neck with the index fingers initially localizing the cricoid cartilage, then moving just below to palpate the isthmus. The head is tilted posteriorly enough to relieve tension of the overlying structures and allow the SCM muscles to displace somewhat laterally. With the tips of two or three fingers overlying the thyroid lobes (Fig. 1C), the examiner may slide the fingers over the thyroid, applying sufficient pressure to feel beneath the overlying structures and outlining the borders of both lobes. With the finger tips then stationary over the thyroid (Fig. 1C), the patient swallows, moving the thyroid under the examiner's fingers.

If nodules are appreciated, the upper and lower borders may be trapped between two examining fingers so as to allow a gross determination of size in the caudo-cranial as well as lateral-medial dimension. A simple pocket ruler is used by many clinicians for this initial measurement. Alternatively the overlying skin may be marked and measured, or tape may be applied to the skin over the nodule, marked to outline the nodule, and adhered to a note in the patient's record to document size.

The normal isthmus has a felt-like consistency and is several millimeters in thickness (1). Extending from the isthmus upward and either left or right of midline, a pyramidal lobe may be palpable. The pyramidal lobe, a vestige of the embryonic thyroglossal duct, is present in up to 80% of thyroids examined at surgery (21). A pyramidal lobe may be palpated in the presence of generalized thyroid enlargement, as seen in Hashimoto's thyroiditis or Graves' disease (21), and may be mistaken for an isthmus nodule or a pretracheal, “delphian” lymph node (5).

During palpation of the thyroid, a vascular thrill may be appreciated, suggesting significantly increased thyroidal blood flow (10,22). Auscultation of the thyroid is important when examining the thyrotoxic patient with goiter. Blood flow is enhanced in the hyperthyroid gland (i.e., Graves' disease), and pulsating murmurs (bruit) may be heard (4,5,6,11). Examination of the thyroid lobes should give the examiner a sense of the size, texture, consistency, and presence of nodules or tenderness. The right lobe may be somewhat larger than the left, and each is expected to be about 4 to 5 cm less in length and 2 to 3 cm in width (4). A thyroid that is both visibly enlarged with the head in the normal position and confirmed by an estimate of increased thyroid size by palpation is highly likely to correlate with increased gland volume on ultrasound and is designated a goiter. Each lobe is estimated to be about the size of the distal phalanx of the individual's thumb (5,6). Estimates of normal adult thyroid volume (weight) in iodine-replete areas of the world range from 10 to 20 g (10,20,23,24) and varies directly by body size, sex, and, to a lesser degree, age (23). The average-sized woman has a thyroid of about 15 g; if the estimate of diffusely hypertrophied lobes, when compared to the patient's thumb, is two or three times normal size, the estimated weight is 30 to 45 g. Correlation with objective methods of thyroid volume measurement have shown this method to be imprecise. Smaller goiters may go undetected, and the size of larger goiters tend to be underestimated (25,26,27). Another method of documenting diffuse thyroidal enlargement is the use of a tape measure to document neck circumference. The tape is positioned at specific landmarks that can be duplicated for serial measurements (10). If the lower borders of the gland cannot be discerned, the goiter may extend retrosternally, and the full extent of the enlargement may be underestimated by the examiner.

The consistency of the normal thyroid tissue is described as rubbery (5). A patient with Graves' disease has a thyroid that feels softer than normal (5), often described as spongy and malleable, similar to the feel of uncooked sirloin steak (10). A spectrum of increasing firmness of the thyroid tissue has been described from the Graves' gland, to colloid goiter and early Hashimoto's thyroiditis. Adenomatous and multinodular goiters are said to be even firmer than those described earlier, and late Hashimoto's glands with extensive fibrosis tend to be very firm (5). Infiltrating primary malignancies and thyroid lymphomas have been described as “stony” hard (15). Fibrotic glands affected by Reidel's thyroiditis have been said to have a woody consisttency (5).

The size, location, and consistency of nodular lesions palpated in the course of the thyroid exam should be noted. When an apparent solitary nodule is palpated, multiple occult nodules are likely to be present in about half of patients (11). Correlation of physical findings and high-resolution ultrasound document show that only about 6% of nodules < 0.5 cm in diameter are palpable; as size increases, more are palpable, but only about one half of the nodules > 2 cm are reliably detected by experienced examiners (28).

Pure cysts are more likely transilluminated by the beam of a penlight pressed against the side of the nodule when compared to absent transmission observed by the unaffected contralateral lobe (10). Readily palpable enlargement of a single (usually right) thyroid lobe and absence of the contralateral (left) lobe is characteristic of the rarely seen (0.05% prevalence) hemiagenesis of a thyroid lobe (29). Fluctuant nodules may be appreciated in acute suppurative thyroiditis (4), inflamed thyroglossal duct cysts (8), and infected branchial cleft cysts (9).

Pain in the thyroid may indicate the presence of thyroiditis. Subacute granulomatous (de Quervain's) thyroiditis (SAT) is usually associated with diffusely distributed severe pain potentially making palpation problematic. Rarely, this diffuse form of thyroidal pain has been observed in Hashimoto's thyroiditis. The pain associated with SAT may occasionally be localized to an isolated area of the gland (4) and then differentiated from other conditions such as acute hemorrhage within a nodule (4), the occasional case of painful malignant thyroid disease, and acute suppurative thyroiditis (10).

Examination requires a careful determination of the presence or absence of enlarged cervical lymph nodes (2,4,7) (Fig. 1D). A palpable node in the central cricoid area anterior to the cricothyroid ligament and just above the isthmus is termed a delphian node and may be the earliest sign of metastatic papillary cancer. The delphian node is not specific to thyroid cancer, as it may also be enlarged in patients with laryngeal cancer (11), subacute granulomatous thyroiditis (4), Graves' disease, and, rarely, in individuals with Hashimoto's thyroiditis (5,10). A differential approach to evaluating the presence of malignancy in palpable thyroid nodules and goiters is outlined in the Table 8.1. Table 8.2 correlates the clinical context and characteristics of palpable thyroid nodules and goiters with differential diagnosis.

TABLE 18.1. CLINICAL FINDINGS AND ASSOCIATION OF MALIGNANCY IN THYROID NODULES


Finding

Favors Benign

Favors Malignant (L.R.)


Pain, tenderness

X

Soft, smooth, mobile

X

Change in nodule size

Firm, hard, irregular nodule

X

Multinodular goiter

?

?

  Dominant nodule

X

Vocal cord paralysis with

Goiter

X (45.2)

  Nodule

X (12.0)

Fixed to surroundings—

Goiter

X (9.7)

  Nodule

X (7.2)

Cervical lymph nodes with

Goiter

X (13.4)

  Nodule

X (7.4)


X, finding when present favors either benign or malignant diagnosis; ↓, decrease in nodule size; ↑, increase in nodule size; L.R., likelihood ratio of malignancy being present;?, data inconsistent. From Boyle JA, Greig WR, Franklin DA, et al. Construction of a model for computer-assisted diagnosis: application to the problem of non-toxic goiter. QJM1966;35:565–588; Hamming JF, Goslings BM, van Steenis GJ, et al. The value of fine needle aspiration biopsy in patients with nodular thyroid disease divided into groups of suspicious of malignant neoplasms on clinical grounds. Arch Intern Med 1990;150:113–116; Belfiore A, La Rosa GL, La Porta GA, et al. Cancer risk in patients with cold thyroid nodules: relevance of iodine intake, sex, age, and multinodularity. Am J Med 1992;93:363–369; Singer P, Cooper DS, Daniels GH, et al. Treatment guidelines for patients with thyroid nodules and well differentiated thyroid cancer. Arch Intern Med 1996;156:2165–2172; Feld S, Garcia M, Baskin HJ, et al. AACE clinical practice guidelines for the diagnosis and management of thyroid nodules. Endocrine Practice 1996;2:80–84; McGee S. The thyroid and its disorders. In: Fathman L, ed. Evidence-based physical diagnosis. Philadelphia: WB Saunders, 2001:271–303; and Blum M, Hussain MA. Evidence and thoughts about thyroid nodules that grow after they have been identified as benign by aspiration cytology. Thyroid 2003;13:637–641, with permission.

TABLE 18.2. CORRELATION OF CLINICAL STATUS WITH PHYSICAL FINDINGS SUGGESTS DIFFERENTIAL DIAGNOSIS


Clinical

Thyroid Palpation

Differential Diagnosis


Euthyroid

Normal size, no nodules

Thyroid disease unlikelya

Diffuse enlargement

Nontoxic goiter, Graves' disease, Hashimoto's thyroiditis, iodine deficiency, silent and postpartum thyroiditis

Nodule

Benign adenoma, thyroid cyst, thyroid carcinoma

Right lobe enlarged

Hemiagenesis of left lobe

Sudden painful enlargement

Hemorrhage; benign, carcinoma, subacute thyroiditis (focal)

Midline mass

Moves with tongue extension

Thyroglossal duct cyst

Moves with thyroid

Pyramidal lobe

Thyrotoxic

No palpable thyroid

Exogenous thyroid ingestion, ectopic thyroid hormone production

Diffuse enlargement (+/- pyramidal lobe)

Graves' disease, nonautoimmune hyperthyroidism, silent and postpartum thyroiditis

Nodular bilateral enlargement

Toxic multinodular goiter

Nodule

Toxic nodule, Graves' with cold nodule, toxic nodular goiter with dominant cold nodule

Hypothyroid

No palpable thyroid

Atrophic thyroiditis, secondary hypothyroidism, S/P 131-I Rx for Graves' disease, S/P thyroidectomy

Diffuse enlargement (+/- pyramidal lobe)

Hashimoto's thyroiditis, iodine deficiency, iodine organification defect, silent and postpartum thyroiditis

Nodule

Thyroid carcinoma, Hashimoto's thyroiditis, thyroid cyst


S/P, status post; Rx, treatment.

aDoes not rule out the presence of small nodules or nonhomogenous tissue consistency.

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30. Boyle JA, Greig WR, Franklin DA, et al. Construction of a model for computer-assisted diagnosis: application to the problem of non-toxic goiter. QJM 1966;35:565–588.

31. Hamming JF, Goslings BM, van Steenis GJ, et al. The value of fine needle aspiration biopsy in patients with nodular thyroid disease divided into groups of suspicious of malignant neoplasms on clinical grounds. Arch Intern Med 1990;150:113–116.

32. Belfiore A, La Rosa GL, La Porta GA, et al. Cancer risk in patients with cold thyroid nodules: relevance of iodine intake, sex, age, and multinodularity. Am J Med 1992;93:363–369.

33. Blum M, Hussain MA. Evidence and thoughts about thyroid nodules that grow after they have been identified as benign by aspiration cytology. Thyroid 2003;13:637–641.