Disorders Of The Thyroid Gland Flashcards
What is a symmetrical enlargement of the thyroid called
Goitre
Name of an asymmetrical enlargement because of focal pathology in an otherwise normal lobe
Solitary nodule
What is characteristic of the neck swelling caused by thyroid enlargement
Occurs in the lower midline of the neck and moves readily on swallowing
Causes of midline enlargement of the neck
- thyroid enlargement
- submental lymphadenopathy
- thyroglossal duct
Causes of lateral neck swelling
- cervical lymphadenopathy (most common)
- salivary gland enlargement
- branchial cyst
- cystic hygroma
- pharyngeal pouch
- carotid body tumour
Causes of a goitre
- physiological: puberty (both sexes), pregnancy and lactation
- simple, non nodular goitre: iodine deficiency (endemic and sporadic)
- multinodular goitre
- thyroiditis: autoimmune, hashimotos, de quervain thyroiditis, riedel thyroiditis
- thyroid carcinoma
Causes of a multinodular goitre
- genetic: familial goitre, Pendred Syndrome
- Goitrogens: anti- thyroid drugs, PAS, sulphonylureas, iodine containing medications, cobalt
When should multinodular goitre be investigated
When malignancy has to be excluded as in the case of a single nodule or when the gland has compressive complications
Diagnosis of thyroiditis
The diagnosis may be made with aspiration cytology or at surgery. In autoimmune thyroiditis and occasionally in other forms, antibodies may be elevated
Causes of solitary thyroid nodule
- hyperplastic/ adenomatous nodule
- simple cyst
- follicular adenoma
- thyroid carcinoma
Investigation of nodular thyromegaly
- ultrasonography
- aspiration cytology
- radio- isotope scanning
- Ct scan
- blood tests: thyroid function, tumour markers (calcitonin), serum thyroid antibodies
Features of malignancy of solitary nodule on ultrasound
Hypoechogenicity of the nodule, marked increase in vascularity, local lymphadenopathy, microcalcifications
Bethesda classification of reporting thyroid cytopathology
1- non diagnostic 2- beneign 3- indeterminate 4- suspicious for follicular neoplasm 5- suspicious for malignancy 6- malignant
Indications for surgery of solitary nodules
- solid nodule as shown on u/s
- cold area on isotope scanning
- cytology which is malignant, suspicious or indeterminate
- cyst which refills after aspiration
Management after a suspicious nodule and containing lobe are removed for histological analysis
- report of beneign disease: no action
- report indicates malignancy: total thyroidectomy is performed for all types of thyroid cancer except small <1 cm, unifocal papillary ca
Features suggestive of malignancy in thyroid mass
- asymmetrical goiter or solitary nodule in children or men
- rapid onset
- progressive increase in size
- pain
- local invasion
- lymphadenopathy
- hoarseness
What are the types of thyroid carcinoma
- well differentiated
- medullary
- anaplastic
- lymphoma
- other
Types of well differentiated carcinomas
They can be classified histological to as papillary, follicular or mixed
Management of well differentiated thyroid carcinomas
Management is surgical complemented by radioactive iodine doses and endocrine therapy (thyroxin). The usual operation is a total thyroidectomy, although a lobectomy may be sufficient in some patients. Lymphadenectomy for patients with lymph node involvement
Adverse prognostic indices of thyroid carcinoma
- older patients
- males
- undifferentiated lesions
- spread to lymph nodes
- distant metastes
Where is medullary carcinoma thought to be derived from
Calcitonin producing C cells
Components of the MEN2 syndrome
Phaeochromocytoma
Hyperparathyroidism
neurofibromatosis
Medullary carcinoma
Treatment of medullary carcinoma
Total thyroidectomy with nodal dissection
Causes of thyrotoxicosis
- Graves’ disease
- toxic multinodular goitre (Plummer’s disease)
- toxic solitary nodule
- Excess TSH (pituitary, paraneoplastic)
- Excess T4 (iatrogenic, paraneoplastic)
- Excess iodine (Jod basedow)
- Transient during thyroiditis/ irradiation
