Thyroid Disease
Dr John McDermott
Consultant Endocrinologist
Connolly Hospital Blanchardstown
Hermitage Medical Clinic
Royal College of Surgeons in Ireland
Thyroid Hormones
• Thyroid gland manufactures and releases
thyroid hormones
• Thyroid hormones are iodine containing
amino acids
• 3, 5, 3’ triiodothyronine = T3
• 3, 5, 3’,5’ tetraiodothyronine = T4
Thyroid Hormones
• ‘Maintain the level of metabolism in the
tissues that is optimal for their normal
function’
• Small amounts secreted continuously
Thyroid Hormones
• Deficiency or excess of thyroid hormones:
 wide and varied symptoms and physical
signs involving any organ system
Thyroid Case
• 33 year old woman
• Gaining weight
• Tired – busy job and 2 young children
• Rows over thermostat
Thyroid Case
• T4: 6
(normal 9 – 22)
• TSH: 36
(normal 0.4 – 4)
• Diagnosis: Hypothyroidism
Other symptoms of hypothyroidism
• Constipation
• Heavy periods
• Cold dry skin, dry hair, hair loss
• Muscle pains/stiffness
Hypothyroidism
• Joseph Fourier, a French mathematician
• ‘began to suffer from a strange disease, whose
main effect was to render him extremely sensitive
to cold….caused him to wrap up in many layers of
heavy clothing, and live in a highly heated room
from which he seldom ventured forth, even in
summer heatwaves’.
Paul Strathern, Napoleon in Egypt
Treatment of Hypothyroidism
• Thyroid hormone, T4 (Eltroxin)
• Aim to abolish symptoms
• Aim to achieve a high normal T4 and lownormal TSH
• NB Pregnancy issues
Thyroid Case [2]
• 26 year old woman
• Noticed prominence of right eye x 3 weeks
• Increased appetite – but weight decreasing
• Difficulty getting out of the bath
On Examination
• Pulse 120 regular
• Tremulous, sweaty hands
• Enlarged, rubbery thyroid
Thyroid Case [2]
• T4: 37
(normal 8 – 22)
• TSH < 0.01
(normal 0.4 – 4)
• Anti-TSH receptor antibodies ++
• Diagnosis: Graves Disease causing
hyperthyroidism, ophthalmopathy
Graves Disease
• Autoimmune condition
• Antibodies against TSH receptor – stimulate
excess thyroid hormone
• Antibodies attack back of eye - proptosis
Treatment of Hyperthyroidism
• Antithyroid drugs:
Carbimazole (Neomercazole)
Propylthiouracil (PTU)
• Radioactive Iodine
• Surgery - thyroidectomy
Radioactive Iodine
• Commonly prescribed treatment for
hyperthyroidism
• Orally-administered I131
• Concentrated in thyroid gland, radiation
destroys thyroid tissue
Radioactive Iodine
• Precautions after dose
• Long-term hypothyroidism
Surgery
• ‘Subtotal’ thyroidectomy
• Hypothyroidism
• Potential other complications
Diseases of the Thyroid
Disorders of function:
• Hyperthyroidism
• Hypothyroidism
Disorders of structure:
• Goitre
• Thyroid nodules/cancer
Goitre
• Enlarged thyroid
• Symptoms: Cosmetic concerns, obstructive
symptoms
• Toxic Multinodular Goitre: hyperthyroidism
Thyroid nodules
• 5% of population have palpable thyroid
nodules
• 30-40% of popn have non-palpable nodules
detectable on ultrasound
• Thyroid cancer in 8% of palpable thyroid
nodules
• Differentiated cancers: slow growing, good
prognosis
Thyroid nodules
• Risk stratify: risk factors, u/s characteristics,
hot or cold
• Fine needle aspiration
• Observation, surgery
Summary
• Thyroid disease common but treatable, wide
and varied complaints
• Disorders of function: Hypo/Hyper,
diagnosis TFTs
• Disorders of structure: Goitre, nodules