7.1 DEFINITION OF GOITRE STAGES

Definition of Goitre

A normal thyroid gland should have the minimal size compatible with euthyroidism under conditions of normal iodine intake (100 to 150 mcg/day). This gland would be non-palpable or barely palpable. For practical purposes, the definition of goitre of Perez et al., (1960) is recommended: "A thyroid gland whose lateral lobes have a volume greater than the terminal phalanges of the thumbs of the person examined will be considered goitrous".

Estimation of Thyroid Size

A slight modification of the system of Perez et al. (1960) is recommended.

Stage 0. No goitre.

Stage 1a. Goitre detectable.

Stage 1b. Goitre palpable and visible only when the neck is fully extended. This stage also includes nodular glands, even if not goitrous; see Section C below.

Stage 2. Goitre visible with the neck in normal position; palpation is not needed for diagnosis.

Stage 3. Very large goitre that can be recognized at a considerable distance.

In case of doubt between any two of these stages, the lower should be recorded.

Measurement of thyroid surfaces by the procedure of MacLennan and Gaitan (1974) is particularly recommended for standardization of technique among different examiners and for comparison of surveys in different areas and at different times.

The total goitre rate is the prevalence of stage 1+2+3; the visible goitre rate is the prevalence of stages 2+3.

This classification is appropriate to field surveys for public health purposes. For clinical purposes, more precise information can be obtained by other techniques including scintigraphy and sonography.

Estimation of the Consistency of the Thyroid by Palpation

The diffuse or nodular consistency of the thyroid should be recorded, for nodules usually occur in areas where marked iodine deficiency has been long-standing. This estimation should be independent of that for the size of the thyroid, with the following exception: when one or more nodules are found in a non-goitrous gland, it will be recorded as Stage 1b since nodularity implies marked modifications in the structure of the gland.