AANP Family Nurse Practitioner (FNP) Certification ExamAssessmentEasy
A 45-year-old female presents with a 3-month history of fatigue, weight gain, cold intolerance, and constipation. Her TSH is 8.2 mIU/L (normal range 0.4-4.0 mIU/L) and free T4 is 0.7 ng/dL (normal range 0.8-1.8 ng/dL). What is the most likely diagnosis?
- AHyperthyroidism
- BSecondary hypothyroidism
- CPrimary hypothyroidism
- DSubclinical hypothyroidism
Show answer & explanationAnswer & explanation
Correct answer: C. Primary hypothyroidism
Primary hypothyroidism is characterized by an elevated TSH and a low free T4, indicating that the thyroid gland itself is failing to produce enough thyroid hormone despite adequate stimulation from the pituitary.
Why the other options are wrong
- A. Hyperthyroidism would present with low TSH and high free T4.
- B. Secondary hypothyroidism would present with a low or normal TSH and a low free T4, due to pituitary dysfunction.
- D. Subclinical hypothyroidism would show an elevated TSH but a normal free T4.
Primary Hypothyroidism
A condition where the thyroid gland fails to produce sufficient thyroid hormones, leading to an elevated TSH and low free T4 levels.
- High TSH, low Free T4.
- Common symptoms: fatigue, weight gain, cold intolerance, constipation.
- Most common cause is Hashimoto's thyroiditis.
Memory trick: TSH and T4: The Thyroid's Dance Partners