The thyroid gland is located in the neck below the thyroid cartilage. It produces the hormones thyroxine and triiodothyronine which are regulated by TSH from the pituitary gland. Hyperthyroidism is more common in women and can cause weight loss, palpitations, tremors and eye symptoms. Hypothyroidism causes tiredness, weight gain, depression and myxedema. Thyroid cancer types include papillary, follicular, anaplastic and medullary carcinomas. The parathyroid glands are usually four in number and located near the thyroid. They secrete parathyroid hormone which raises blood calcium levels by stimulating bone resorption and kidney reabsorption of

1. Thyroid and Parathyroid
Julie Cornish
General Surgical SpR

3. Location of Thyroid Gland
•Located just below thyroid cartilage
• Isthmus is midway between apex of thyroid cartilage (“Adams
apple”) and suprasternal notch

6. origin of the thyroid gland?
• originates from the floor of the pharynx
• outpouching which grows downward in front of
trachea (Thyroglossal duct)
• bifurcates and forms a series of cellular cords
which in turn form follicles and the lateral lobe
• remnants of the thyroglossal duct can be seen in
the adult as cysts (mucus-filled, lined with
squamous epithelium) or in the pyramidal lobe

7. Thyroid
development

9. function of thyroid gland
• hormone production
– Thyroxine (T4)
– Tri-iodothyronine (T3)
• produced in lumen of thyroid follicle
• synthesis and release – controlled by TSH
• TSH released from ant. pituitary
• controlled by TRH from hypothalamus

11. hyperthyroidism
• incidence = 20/1000 females
• 5 x less common in men
• causes
– Graves disease
– multinodular goitre
– thyroiditis
– iodide induced
– TSH induced

13. clinical features
• goitre
• D+V
• weight loss
• palpitations / AF / sinus tachycardia
• tremor
• proximal myopathy
• pretibial myxoedema
• eye signs – lid lag, exomphalos

14. classification -hypothyroidism
• Goitrous
– Hashimotos thyroiditis
– Drug induced (lithium, iodine)
– Iodide deficiency
– Dyshormonogenesis - rare
• Post ablative
• Transient (e.g. post subtotal thyroidectomy)
• Subclinical
• Congenital

16. clinical features
• tiredness
• weight gain
• cold intolerance
• goitre
• hoarseness
• depression
• alopecia
• myxoedema

17. classification - thyroid cancer
• <1% of all malignancies
• Follicular cells
– Papillary carcinoma (70%)
– Follicular carcinoma (10%)
– Anaplastic carcinoma (undifferentiated) (5%)
• Parafollicular C cells
– Medullary carcinoma (5-10%)
• Lymphocytes
– Lymphoma (5-10%)

18. investigation
• FNA
• USS +/- guided biopsy
• CT
• Radio-isotope imaging
• Larygoscopy

19. Mx thyroid nodule disease
• Indications for surgery
– cytological features of follicular lesion/medullary
Ca/ papillary Ca
– clinical suspicion of malignancy (despite –ve bx)
– pressure symptoms/ tracheal compression
– thyroid toxicity
–  size goitre
– patient preference

20. Mx of Graves Disease
• MDT
• treatment options
– anti-thyroid drugs (carbimazole)
– beta blockers
– radioactive iodine ablation
– surgery
• indications for surgery
– when other treatments failed
– patient preference
– pregnancy / planning pregnancy

21. Surgical Access
• Supine patient, neck extended
• Transverse incision (2 finger breadths above clavicle)
• Deepen incision through platysma
• Down to lateral border of sternomastoid
• Identify anterior jugular veins
• Incise along midline raphe between strap muscles
• Create tissue plane between strap muscles and
thyroid

24. total thyroidectomy
• aim to preserve at least 1 parathyroid gland
• if in doubt – remove a damaged gland, mince
it and implant pieces into sternomastoid
/forearm muscle
• but not in malignant disease
• following implantation – function takes 3
months to recover

25. Postop Mx
• Serum calcium to be checked
• Hypocalcaemia
– Trousseau’s sign
– Chvostek’s sign
• Mx of hypocalcaemia

26. complications of thyroidectomy
• recurrent laryngeal nerve damage
– national incidence 5%
• Hoarseness (if > 2-3 days =external laryngeal nerve damage)
• postoperative haemorrhage
• keloid scar
• thyroid crisis
• temporary/permanent hypoparathyroidism
– 30% transient hypocalcaemia
• Tracheomalacia - rare

27. Parathyroid gland
• At least 4 glands in the region of the thyroid
gland
• 3 cell types
– adipose cells
– chief cells
– oxyphil cells
• Parathyroid hormone (PTH)
– peptide that raises serum calcium
– produced by Chief cells

30. Regulation of blood levels of calcium
• Thyroid C cells or parafollicular cells
• lie outside follicles either in clusters, or singly
• produce the peptide hormone, calcitonin
• protein synthesizing organelles prominent
• Calcitonin
– inhibits calcium resorption from bones
– lowers blood calcium
– regulated by calcium levels
– high calcium will stimulate its release

31. Parafollicular or C cells
C Cells labeled immunocytochemically for calcitonin
Thyroid follicle
C-Cells

32. Parathyroid hormone functions
• stimulates osteoclasts
• resorption of bone
• stimulates kidney proximal tubule
• reabsorption of calcium
• promotes absorption of calcium from the
small intestine
• raises calcium levels; regulated by calcium
itself

33. Regulation and feedback
Calcium levels
Calcium levels
Parathyroid hormone levels
Parathyroid hormone levels

34. parathyroidectomy
• primary hyperparathyroidism
– PTH secreted from parathyroid adenoma (90%)
– Multiple adenomata (4%)
– Nodular hyperplasia (5%)
– carcinoma (1%)
• clinical features:
– anorexia, wt loss, N+V, constipation, weakness
• Ix:
– serum Ca 2+
, PTH 
– USS/ CT scan + radio-isotope injection to isolate gland