Endocrine and metabolic · Easy
This case is fictional and exists for study. It describes no real patient.
34 years · female
A 34-year-old woman presents to her general practitioner with a 2-month history of progressive fatigue, a 5 kg unintentional weight loss despite an increased appetite, heat intolerance, and frequent loose bowel movements. She also reports feeling constantly anxious and experiencing heart palpitations. She takes no regular medications and has no past medical history. On examination, she exhibits a fine postural tremor of her hands, warm moist skin, and a diffusely enlarged, non-tender thyroid gland with an audible bruit. Ophthalmic examination demonstrates mild lid lag and lid retraction without proptosis or eye pain.
Vital signs
- HR
- 108 bpm
- BP
- 132/82 mmHg
- RR
- 16/min
- Temp
- 37.1 °C
- SpO₂
- 98%
Examination findings
- Diffuse, smooth, non-tender thyroid enlargement with an audible thyroid bruit
- Fine postural tremor of outstretched hands and warm, moist skin
- Lid lag and lid retraction present
Investigations
| Serum TSH | < 0.01 mU/L | reference: 0.40 - 4.00 |
| Free T4 | 38.5 pmol/L | reference: 9.0 - 23.0 |
| Free T3 | 12.4 pmol/L | reference: 3.1 - 6.8 |
Question 1 of 3
Based on the clinical presentation and laboratory results, what is the most likely diagnosis?
Graves' disease is the most common cause of hyperthyroidism in young females. It presents with features of thyrotoxicosis, suppressed TSH, elevated free T4/T3, and characteristic examination findings such as a diffuse non-tender goitre with a thyroid bruit and eye signs (lid lag/retraction). Subacute thyroiditis typically features a painful, tender thyroid gland following a viral illness. Toxic multinodular goitre affects older adults and shows irregular thyroid nodules on examination. Hashimoto's thyroiditis causes hypothyroidism, though a transient early hyperthyroid phase (hashitoxicosis) can occur, it lacks a thyroid bruit and eye signs.
Teaching point: A diffuse non-tender goitre with an audible thyroid bruit and eye signs in a young hyperthyroid patient is characteristic of Graves' disease.
Question 2 of 3
Which of the following is the most appropriate next step for immediate relief of this patient's adrenergic symptoms?
Non-selective beta-blockers such as propranolol provide rapid control of adrenergic symptoms (palpitations, tremor, anxiety, and tachycardia) in thyrotoxic patients while definitive therapy takes effect. Levothyroxine is used to treat hypothyroidism. Radioactive iodine ablation and thyroidectomy are definitive second-line management options and do not offer immediate symptom relief.
Teaching point: Propranolol is the standard initial therapy for rapid control of adrenergic symptoms in patients with hyperthyroidism.
Question 3 of 3
Which antithyroid medication is the first-line choice for definitive medical management to reduce thyroid hormone synthesis in this patient?
Carbimazole is the first-line antithyroid drug recommended in the UK for non-pregnant adult patients with Graves' disease. Propylthiouracil is reserved for the first trimester of pregnancy or cases of carbimazole intolerance due to its risk of severe hepatotoxicity. Amiodarone is an antiarrhythmic that can induce thyroid dysfunction. Prednisolone is indicated for severe subacute thyroiditis or thyroid storm, not routine primary medical therapy for Graves' disease.
Teaching point: Carbimazole is the first-line disease-modifying medical treatment for non-pregnant patients with Graves' disease.
Key learning points
- Graves' disease presents with biochemical hyperthyroidism (suppressed TSH, raised T4/T3) and characteristic signs such as a diffuse goitre with a bruit and thyroid eye disease.
- Beta-blockers like propranolol should be started promptly to manage sympathetic symptoms like tachycardia and tremors.
- Carbimazole is the preferred first-line antithyroid drug for controlling hormone production in non-pregnant individuals.
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