ERS Case 2: Hyperthyroidism

Question 1

Explain the structure, embryology and anatomy of thyroid and parathyroid gland

Answer 1

See lecture

Question 2

Mechanism of thyroid hormone biosynthesis, control of secretion and physiological effects of hormone excess and deficiency

Answer 2

See lecture

• **Excess:
• Weight loss
• Appetite increase
• Hyperactive
• Diarrhoea
• Heat intolerance
• Tachycardia
• Warm and sweaty
• Fine hand tremor
• Oligomenorrhoea
• **Deficiency:
• Weight gain
• Appetite decrease
• Slowdown of mental
• Constipation
• Cold intolerance
• Bradycardia
• Dry + Myxedema
• Ankle jerk relaxation slow
• Menorrhagia

Question 3

Pathology and Immunological factors involved in thyroid disorder

Answer 3

See lecture

Graves’

1. Thyroid stimulating Ig
2. Thyroid growth stimulating Ig
3. TSH-binding inhibiting Ig

Pathology

• ↑ size in gland uniformly —> Homogenous enlarged thyroid / Diffuse parenchymatous hyperplasia
• ↑ number of follicles
• ↑ vascularity

Question 4

Pharmacological agents in treatment of thyroid disorders

Answer 4

See lecture

Question 5

Understanding of clinical, biochemical and radiological investigation of thyroid axis

Answer 5

Clinical:

• Diffuse goitre with **thrill + **bruit
• Hyperthyroidism symptoms
• Exophthalmos

Biochemical:
- T3, T4, TSH
- Thyroid AutoAb
—> Thyroid stimulating Ig, Thyroid growth stimulating Ig, TSH-binding inhibiting Ig
—> Anti-Thyroglobulin
—> Anti-Thyroid microsomal Ab

Radiological:

• Ultrasound
• Radioiodine scan / Tc-99m scintigraphy

Question 6

Importance of selecting appropriate treatment for individual patients

Answer 6

1. Age
2. Compliance
3. Size of goitre
4. Presence of thyrotoxic eye problem
5. Recurrence

Question 7

Cost-effectiveness of individual treatment option

Answer 7

1. Favourable patient factors
Anti-thyroid drugs:
- ***Pregnancy, lactation
- children, adolescents
- moderate-severe active ophthalmopathy
- not able to follow radiation safety precautions
RAI:
- high risk of relapse
- ***Recurrent Graves’
Surgery:
- ***Compressive symptoms

2. Advantages
   Anti-thyroid drugs: **non-invasive, cheap
   RAI: **cost effective, few SE, out-patient therapy
   Surgery: ***rapid and effective
3. Disadvantages
   Anti-thyroid drugs: **low rate of remission, SE: fever, rash, arthralgia, agranulocytosis
   RAI: radiation exposure, risk of exacerbation of ophthalmopathy, **need to delay pregnancy and avoid breastfeeding
   Surgery: high cost, painful, scar, need hospitalisation, ***surgical complications: Recurrent laryngeal nerve damage, Hypoparathyroidism

Question 8

Examine patient with thyroid disorder

Answer 8

Sit up with neck slightly extended

Inspection:
- ask patient to swallow and observe for enlarged thyroid gland that moves ***up during swallowing

Palpation:

• ask for pain before palpation
• both hands while asking patient to swallow again
• size, shape, mobility, consistency, tenderness, thrills of nodules, symmetry
• any cervical lymphadenopathy

Auscultation:

• hold breath
• auscultate for bruit —> indicate ↑ vascularity

Others:
Other signs of hyperthyroidism

Question 9

Interpret laboratory results

Answer 9

Biochemical:

• ↑ T3, T4
• ↓ TSH
• Thyroid stimulating Ig, Thyroid growth stimulating Ig, TSH-binding inhibiting Ig

Radiological
- Diffuse uptake of iodine