Goitre And Nodules

Overview

Overview Goitre refers to an enlarged thyroid gland. Thyroid nodules are common in the general population, especially in women. Goitre results from follicular cell hyperplasia at one or multiple sites within the thyroid gland. Goitre can be classified based on morphology into diffuse or nodular.

Nodular thyroid denotes the presence of single or multiple palpable or nonpalpable nodules within the thyroid gland.

Prevalence rates range from 5 to 50%. Factors associated with increasing numbers and size of thyroid nodules include Graves disease and pregnancy. Low iodine intake is associated with an increased incidence of hyperfunctioning nodules (also called toxic adenomas). Thyroid nodules always raise the concern of cancer, although <5% are cancerous.

Definition
Goitre: Enlarged thyroid gland (Latin gutur meaning throat)
Thyroid Nodule: Cause of goitre. It is a discrete lesion distinct from the surrounding thyroid parenchyma. Most nodules are benign and only 5% to 12% of the nodules detected on ultrasonography are malignant. Most thyroid nodules, including thyroid cancers, are asymptomatic.

Classification

Thyroid Nodule based on Morphology
Diffuse	Nodular
Pregnancy	Multinodular goitre
Graves Disease	Adenoma
Hashimoto's Disease	Carcinoma
Drug induced (lithium, amiodarone)
Iodine Deficiency

Thyroid Nodule based on Thyroid function status
Toxic	Non-toxic (simple)
Graves Disease	Pregnancy
Thyroiditis	Drug induced (lithium, amiodarone)
Multinodular goitre	Iodine Deficiency

Risk Factors

Risk Factors raising suspicion of thyroid malignancy

Age (<20 or >60)

Rapidly enlarging nodule

Localised symptoms including dysphagia, stridor or hoarseness

Previous exposure to radiation

Family History

Familial polyposis coli

Lymphadenopathy

Hashimoto disease

Signs and Symptoms

Asymptomatic
Often noticed by patients as a lump or protrusion in the lower anterior neck
Dysphagia or a choking sensation (Large nodules)
Cough (Large nodules)

Clinical Examination Nodules may be:

single or multiple
hard or soft
tender or nontender.

Remember Thyroid lump with normal TFT is thyroid malignancy until proven otherwise

Malignancy

Firm or hard non-tender nodule
fixation to adjacent tissue
Pemberton's sign

Side note Pemberton's sign is facial erythema and jugular venous distension upon raising the arms. It is a sign of superior venacaval obstruction caused by a substernal mass.

Differential Diagnosis

AETIOLOGY OF GOITRE
Diffuse	Nodular
Pregnancy	Multinodular goitre
Graves Disease	Adenoma
Hashimoto's Disease	Carcinoma
Subacute thyroiditis (de Quervain's)
Drug induced (lithium, amiodarone)
Endemic (iodine deficiency)

Differential Diagnosis of Neck Swelling
Congenital conditions	Thyroglossal tract abnormalities Brachial cyct
Tumours	Thyroid Salivary glands Carotid body (Chemodectoma) Sarcoma Lipoma
Lymph nodes	Primary Malignancy (Lymphoma, leukemia) Secondary Malignancy (oesophagus, mouth, nasopharynx) Inflammatory Conditions (tonsilitis, mononucleosis, HIV)
Diverticulae	Oesophagus

Investigations

The primary goal when evaluating a thyroid nodule is to determine whether it is malignant.

First line Investigations

TSH levels
Thyroid ultrasonography

If ↓TSH

Radionuclide scintigraphy with technetium 99m or iodine 123
- Hyperfunctioning nodules (toxic adenoma) OR
- Entire thyroid gland is overactive (toxic multinodular goiter) OR
- Hypofunctioning nodule (most likely cancer)

If TSH normal or ↑TSH

Fine Needle Aspiration Ultrasound Guided - one of four results:
- Malignant
- Suspicious
- Benign nodule
- Indeterminate or nondiagnostic

Remember Fine Needle Aspiration is for diagnosing malignancy

Aetiology

AETIOLOGY OF GOITRE
Diffuse	Nodular
Physiological (Pregnancy)	Multinodular giotre
Graves Disease	Adenoma
Hashimoto's Disease	Carcinoma
Subacute thyroiditis (de Quervain's)
Drug induced (lithium, amiodarone)
Endemic (iodine deficiency)

Remember Thyroid Carcinomas are mainly follicular or papillary (most common). Medullary cancers are rare.

Management

Non-toxic goitre

Observation
Iodine supplement

Toxic Goitre (overactive thyroid or nodule)

Antithyroid drugs
Radioiodine
Surgery

Malignant/suspicious thyroid or nodule

Surgery - partial or total thyroidectomy +/- lymph node involvement
- Check thyroidglobulin levels (should be low) following thyroidectomy
- Consider suppressing TSH

Indication for thyroid surgery

Troubling compressive symptoms

Fail to respond to medical therapy

Suspicious thyroid nodule

Malignant thyroid nodule

Cosmetic