Hypothyroidism

Question 1

Discuss the Hypothalamic-pituitary-thyroid?

Answer 1

Hypothalamus → THR ⇒ pituitary → TSH ⇒ Thyroid → T3,4

negative feedback on all the above

Question 2

What is the Difference between T3, T4 and synthesis?

Answer 2

• lodide ions enters the thyroid follicular cell by active pumping.
• lodide is converted to iodine by Thyroid peroxidase
• Iodine combines with tyrosine forming: monoiodotyrisine (MIT) and diodotyrosine (DIT).
• MIT + DIT = T3 (triiodotyrosine).
• DIT + DIT = T4 (tetraiodotyrosine).

Question 3

A 65-year-old woman presents with long standing goitre, she also describes general malaise and chronic fatigue.

What kind of anemia can the patient develop as a result of hypothyroidism?

Answer 3

1. Normocytic: decreased erythropoietin
2. Macrocytic: associated autoimmune disease affecting parietal cells → lack of absorption of vitamin B12

Question 4

A 65-year-old woman presents with long standing goitre, she also describes general malaise and chronic fatigue.

What are the most important clinical signs that would show in this patient?

Answer 4

1. Metabolic: Bradycardia, Cold, weight gain
2. Mental: depression, Memory problems
3. Abdominal: Constipation, irregular heavy menstruation
4. Other: weakness, myxoedema accumulation of polysaccharides in skin & CT

Question 5

Discuss the different possible aetiologies of hypothyroidism?

Answer 5

• Primary
  
  1. Genetic, Congenital
  2. Idiopathic, Iatrogenic (thyroidectomy , drugs carbimazole)
  3. Autoimmune Hashimoto’s, Transient Thyroiditis (De Quervain’s thyroiditis)
  4. Iodine deficiency, Infiltrative (amyloidosis, sarcoidosis)
• Secondary
  
  • Pituitary → TSH deficiency
  • Hypothalamic

Question 6

A 65-year-old woman presents with long standing goitre, she also describes general malaise and chronic fatigue.

what are the risks associated with having surgery in this patient?

Answer 6

1. Pre-operative: Anemia, Arrythmia
2. Intra-operative: Low heart rate, blood pressure, and temperature.
3. Post-operative: Delayed recovery, myxedema coma (impairment of multiple organ systems), and delayed wound healing.

Involve anaesthetist and endocrinologist

Question 7

what are the complications of thyroidectomy?

Answer 7

1. Pain
2. Infection
3. Bleeding: haematoma requiring emergent release of sutures
4. Scar: keloid
5. Nerve damage: RLN, ELN (loss of high pitched voice)
6. Parathyroid insufficiency : hypocalcaemia
7. Thyroid insufficiency

Question 8

How could you increase the compliance of this patient to their thyroid medicaitons?

Answer 8

1. Simplify regimen
2. Explain consequences of missing
3. FU: GP/ family
4. Address reasons for potential non-compliance