Consider the following statements regarding 'Factitious Thyrotoxicosis': 1. Induced when patients consume excessive amounts of levothyroxine. 2. The exogenous levothyroxine suppresses secretion of pituitary TSH (thyroid-stimulating hormone). 3. Serum thyroglobulin level is elevated. 4. T4 : T3 ratio is high. Which of the statements given above are correct?
1, 2 and 4
Factitious thyrotoxicosis results from surreptitious excess levothyroxine ingestion (statement 1), which suppresses pituitary TSH via negative feedback (statement 2). Since it is exogenous hormone, endogenous thyroid production and thyroglobulin are suppressed, so serum thyroglobulin is characteristically LOW/undetectable (statement 3 is false), a key feature distinguishing it from thyroiditis. As levothyroxine is pure T4, the T4:T3 ratio is high (statement 4 true). Hence 1, 2 and 4 are correct.
Important Questions from Thyroid Disorders
- Pretibial myxedema is a clinical feature of:
- A 24 year female presented with generalized weakness. Her thyroid function test is as follows. Serum $T_3$ = Normal, $T_4$ = Normal, TSH = 10mU/L. What is the most likely diagnosis?
- A 30-year woman in first trimester of pregnancy has Graves' disease. The treatment of choice is:
- Which one of the following statements is NOT true regarding the thyroid function/disorder in pregnancy?
- A young lady presents in outdoor clinic with complaints of menstrual irregularity, weight gain, hair loss, tiredness and weakness. What will be the investigation of choice?
