Coordination and control – the endocrine system

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Question 5
Hard

Doctors can diagnose subclinical hypothyroidism by measuring the level of Thyroid Stimulating Hormone (TSH) in a patient's blood.

  • If the TSH level is strictly above 4.5 mU/L4.5\text{ mU/L}4.5 mU/L, this suggests the patient may have hypothyroidism.
  • A patient has her TSH levels monitored monthly over a six-month period as shown in the table below:
MonthTSH level (mU/L\text{mU/L}mU/L)
July4.8
August4.2
September4.5
October5.1
November4.4
December5.3
a.

Calculate the percentage of the monthly readings that are strictly above the threshold of 4.5 mU/L4.5\text{ mU/L}4.5 mU/L.

[2]
b.

Suggest two further steps or laboratory investigations the doctor should take to confirm whether the patient has permanent hypothyroidism.

[2]
c.

The doctor discusses a treatment option called levothyroxine (thyroid hormone replacement) with the patient, providing her with the following information:

Information about Levothyroxine treatment:

  • Benefits: Relieves symptoms such as fatigue, weight gain, and cold intolerance. Reduces the risk of developing high cholesterol.
  • Risks/Considerations:
    • Can cause bone thinning (osteoporosis) if the dose is too high, especially in postmenopausal women.
    • Increases the risk of an irregular heart rate (atrial fibrillation) in patients over the age of 65.
    • Requires life-long periodic blood tests to monitor thyroid levels and adjust doses.

The patient is a 68-year-old female with mild fatigue who has a strong family history of osteoporosis.

Discuss the factors this specific patient should consider when making her decision about whether to start levothyroxine treatment.

[4]

Coordination and control – the endocrine system Questions

  1. GCSE
  2. /Biology
  3. /Coordination and control – the endocrine system