Thyroid Flashcards
Goiter
Chronic enlargement of the thyroid gland not due to neoplasm
- Endemic goiter
- Areas where > 5% of children 6-12 years of age have goiter
- Common in China and central Africa
- Sporadic goiter
- Areas where < 5% of children 6-12 years of age have goiter
- Multinodular goiter in sporatic areas often denotes the presence of multiple nodules rather than gross gland enlargement
- Familial
Etiology of Goiter
Hashimoto’s thyroiditis
- Early stages only, late stages show atrophic changes
- May present with hypo, hyper, or euthyroid states
Graves’ disease
- Due to chronic stimulation of TSH receptor
Diet
- Brassica (cabbage, turnips, cauliflower, broccoli)
- Cassava
Chronic Iodine excess
-Iodine excess leads to increased colloid formation and can prevent hormone release
-If a patient does not develop iodine leak, excess iodine can lead to goiter
Medications
- Lithium prevents release of hormone, causes goiter in 6% of chronic users
Neoplasm
Pathogenesis of Goiter
- Iodine deficient areas
- Heterogeneous response to TSH
- Chronic stimulation leads to multiple nodules
- Iodine replete areas
- Thyroid follicles are heterogeneous in their growth and activity potential
- Autopsy series show MNG >30%.
- Thyroid function evaluation
- TSH, T4, T3
- Overt hyperthyroidism (TSH low, T3/T4 high)
- Subclinical hyperthyroidism (TSH low, T3/T4 normal)
Determination of thyroid state is key in determining treatment
Investigations of Goiter
- Isotope scan
- Ultrasound
Hyperthyroidism
excess thyroid hormones from overactivity of the thyroid gland
Causes of hyperthyroidism
- Graves’ disease
- Toxic adenoma ‘hot nodule’
- Toxic multinodular Goiter
Surgical Treatment
- Subtotal Thyroidectomy, Total Thyroidectomy
- Hemi Thyroidectomy with contra-lateral subtotal
- ATD and RAI Rx are very efficacious and easy – so
Surgical treatment is reserved for MNG with
- Severe hyperthyroidism in children
- Pregnant women who can’t tolerate ATD
- Large goiters with severe Ophthalmopathy
- Large MNGs with pressure symptoms
- Who require quick normalization of thyroid function
Preoperative Preparation
ATD to reduce hyper function before surgery
- βeta blockers to titrate pulse rate to 80/min
- SSKI 1 to 2 drops bid for 14 days
- This will reduce thyroid blood flow and there by reduce per operative bleeding
Be careful of recurrent laryngeal nerve damage
Hypoparathyroidism is a complications
Thyroid Cancers
Papillary 80% Follicular 11% Hürthle 3% Medullary 4% Anaplastic 2%
Thyroid Cancer- Diagnosis
- Cytology
- Scans
- Technetium
- Radioiodine
- Sestamibi
- MR/CT/PET
- Ultrasound
- Frozen Sections
- Fixed Sections
Thyroid Cancer - Surgery
Standard:
- total thyroidectomy (TT) with central lymph-node dissection (identification of recurrent laryngeal nerves and parathyroid glands)
Exeption: I. unifocal PTC (pT1a, no lymph nodes)
II. solitary, „minimal invasive” EFC, young pt. (<40 years)
Extended:
- TT with modified radical neck dissection (MRND) (lateral or mediastinal lymph-node dissection)
Completion:
- Inadequate primary surgical procedures (preferably within 8 days)
Surgery of the Parathyroids
Indications:
- Hypercalcaemia in all patients below 50 years.
- Hypercalcaemia greater than 3.00 mmol/l in all age groups.
- Symptomatic hypercalcaemia in all age groups.
- Deterioration in renal function.
- Progressive reduction in bone density.
- Excessive excretion of calcium in the urine.
- Any suggestion of malignant parathyroid disease
Abnormalities of Parathyroids
- Asymptomatic primary hyperparathyroism
- Symptomatic primary hyperparathyroism
- Solitary adenoma 80-85 %
- Multiplex adenoma 2-3%
- Hyperplasia 12-15%
- Cancer 1-3%
- MEN I. and II.
- Secondary / tertiary hyperparathyroism
Types of operations of Parathyroid
Adenoma exstirpation
- Subtotal parathyroidectomy
- Totalis parathyroidectomy + autoTX
- Minimal invasive parathyroidectomy
- Radioguided parathyroidectomy
Surgery of the Adrenal Glands
Diseases:
- Primary Hyperaldosteronism
- Hypertension with or without hypokalemia
- Elevated aldosterone secretion and suppressed plasma renin activation
- Metabolic alkalosis, relative hypernatremia
- Weakness, polyuria, paresthesia, tetany, cramps due to hypokalemia
- Hyperadrenocortism (Cushing’s Disease and Cushing Syndrome)
- Facial plethora (moon face), dorsocervical fat pad (buffalo hump), supraclavicular fat pad, truncal obesity, easy bruising
- Purple striae, acne, hirtuism, impotence or amenorrhea, muscle weakness and psychosis
- Hypertension and hyperglycemia
- Pheochromocytoma
- Episodic headache, excessive sweating, palpitations, visual blurring, hypertension, postural tachycardia and hypotension
- elevated urine catecholamines or their metabolites, hypermetabolism, hyperglycemia
