Clinical Presentation and Diagnosis

Goiter is classified according to the size of the thyroid gland on inspection and palpation, and the following grading system was proposed by WHO in I96032: Stage 0: no goiter

Stage la: goiter detectable only by palpation and not visible even when the neck is fully extended Stabe lb: goiter palpable but visible only when the neck is fully extended Stage II: goiter visible with the neck in the normal position; palpation is not needed for diagnosis

FIGURE 3-2. Classification of goiter size. 1, Stage la: goiter palpable but not visible. 2, Stage lb: goiter visible when neck extended. 3, Stage II: goiter visible in normal neck extension. 4, Stage III: goiter visible at a distance. (From Perez C, Scrimshaw NS, Munoz JA. Technique of endemic goitre surveys. In: Endemic Goiter, Monograph Series No. 44. Geneva, Switzerland, World Health Organization, 1960, p 369.)

FIGURE 3-2. Classification of goiter size. 1, Stage la: goiter palpable but not visible. 2, Stage lb: goiter visible when neck extended. 3, Stage II: goiter visible in normal neck extension. 4, Stage III: goiter visible at a distance. (From Perez C, Scrimshaw NS, Munoz JA. Technique of endemic goitre surveys. In: Endemic Goiter, Monograph Series No. 44. Geneva, Switzerland, World Health Organization, 1960, p 369.)

Stage III: very large goiter that can be recognized at a considerable distance (Fig. 3-2)

Because of observer variation in the measurement of goiter by inspection and palpation, the WHO/UNICEF/ ICCIDD Consultation on IDD indicators in November 1992 recommended a simplified classification of goiter by combining the previous stages la and lb into a single grade (grade 1) and combining stages II and III into grade 2.3 The sum of grades 1 and 2 is taken as the total goiter rate. The simplicity of this assessment allows for easy training of field staff in public health surveys.

• Grade 0: no palpable or visible goiter

• Grade 1: a mass in the neck that is consistent with an enlarged thyroid that is palpable but not visible when the neck is in the neutral position; it also moves upward in the neck as the subject swallows

• Grade 2: a swelling in the neck that is visible when the neck is in a neutral position and is consistent with an enlarged thyroid when the neck is palpated

In areas of mild endemicity where the goiter rate is low and goiters are generally small (i.e., grade 1 or bordering on either grade 0 or 2), interobserver variations can be as high as 40%. Ultrasonography is therefore recommended by WHO as a safe, noninvasive method for providing a more precise and objective measurement of thyroid volume than inspection and palpation.33

The most common form of goiter in children is a diffuse thyroid enlargement. Nodularity may occur at a young age, and the finding of a small, solitary, palpable nodule in adolescence is common. Some diffuse goiters persist into adulthood, or the main bulk of the goiter may be replaced by multiple nodules that form a multinodular goiter, simulating a bag of marbles on palpation.

Functionally, the individual often remains clinically euthyroid despite biochemical evidence of hypothyroidism, with low or normal serum T4 concentrations and minimally elevated serum TSH levels. Scintigraphy of the thyroid in endemic areas may show marked heterogeneity in the uptake of radioiodine and formation of hot or cold nodules. Autonomous function of the nodules leads to failure of 131I or 123I suppression with T3 and absence of TSH response to TRH. Hyperthyroidism in older patients with endemic goiter may be precipitated by iodination and cause Jodbasedow hyperthyroidism.34

Endemic cretinism is a sequela of severe iodine deficiency in which intrauterine growth is affected by deficiencies of maternal T4 and dietary iodine. The infant is born with mental retardation and either (1) a predominantly neurologic syndrome of hearing and speech defects and varying degrees of characteristic stance and gait disorders or (2) predominant hypothyroidism and stunted growth. These changes are preventable with iodine prophylaxis but are not curable once they have occurred.

Mechanical problems often arise in patients with huge goiters that cause tracheal deviation and compression. Large, substernal, or retrosternal goiter can cause venous congestion and the development of collateral venous circulation on the chest wall (Fig. 3-3). Surgical treatment is indicated in such patients.

The presence of hard nodules suggests possible malignant disease, although an increase in the number of thyroid cancers in endemic goiter remains controversial.35-36

FIGURE 3-3. Large goiter with thoracic inlet obstruction. (From De Smet MP. Pathological anatomy of endemic goiter. In: Endemic Goiter, Monograph Series No. 44. Geneva, Switzerland, World Health Organization, 1960, p 338.)

Follicular and anaplastic carcinoma are more common in areas of endemic goiter. The diagnosis is often delayed in such patients because goiters are so common in iodine-deficient areas. Fine-needle aspiration biopsy helps select patients for thyroidectomy.37

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