WBR0246

Author	PageAuthor::Vendhan Ramanujam
Exam Type	ExamType::USMLE Step 2 CK
Main Category	MainCategory::Internal medicine
Sub Category	SubCategory::Endocrine
Prompt	[[Prompt::A 30 year old male presents with fatigue, decreased appetite, weight gain, constipation and cold intolerance. He recalls no event of stress. He does not take any medications. He is a non-smoker and a non alcoholic. His pulse is 48/min and blood pressure is 146/90 mmHg. Physical examination reveals cold extremities, pale skin, coarse hair and brittle nails. There is delayed relaxation of deep tendon reflexes. The thyroid gland is normal on palpitation. Laboratory studies reveal increased serum free T3 and T4 but normal serum TSH level. Which is the most likely diagnosis?]]
Answer A	AnswerA::Subclinical hypothyroidism
Answer A Explanation	AnswerAExp::'''Incorrect'''-Mildly elevated serum TSH levels and normal circulating thyroid hormone levels characterize subclinical hypothyroidism. Patients do not have clinical features of hypothyroidism.
Answer B	AnswerB::Primary hypothyroidism
Answer B Explanation	AnswerBExp::'''Incorrect'''-Low circulating levels of thyroid hormones with TSH levels more than 10 IU/L characterizes primary hypothyroidism.
Answer C	AnswerC::Central hypothyroidism
Answer C Explanation	AnswerCExp::'''Incorrect'''-Secondary and tertiary are central hypothyroidism. Low circulating thyroid hormone levels with low or inappropriate normal TSH levels characterize them.
Answer D	AnswerD::Sick euthyroid syndrome
Answer D Explanation	[[AnswerDExp::Incorrect-In sick euthyroid syndrome, the abnormality pattern is usually a low total or free T3 level with normal T4 and TSH levels, due to decrease in the peripheral conversion of T4 to T3 following a severe illness.]]
Answer E	AnswerE::Generalized resistance to thyroid hormones
Answer E Explanation	[[AnswerEExp::Correct-Besides primary, secondary and tertiary hypothyroidism, rarely generalized resistance to thyroid hormones may cause hypothyroidism. Generalized resistance to thyroid hormones results from a receptor defect in the peripheral tissues. They usually present at an early age with growth and mental retardation, however patients with milder defects can present later in life. Elevated circulating thyroid hormone levels with normal or elevated TSH levels are characteristic. They present with hypothyroidism despite having elevated thyroid hormone levels.]]
Right Answer	RightAnswer::E
Explanation	[[Explanation::Besides primary, secondary and tertiary hypothyroidism, rarely generalized resistance to thyroid hormones may cause hypothyroidism. Generalized resistance to thyroid hormones results from a receptor defect in the peripheral tissues. They usually present at an early age with growth and mental retardation, however patients with milder defects can present later in life. Elevated circulating thyroid hormone levels with normal or elevated TSH levels are characteristic. They present with hypothyroidism despite having elevated thyroid hormone levels. Educational Objective: Elevated circulating thyroid hormone levels with normal or elevated TSH levels with features of hypothyroidism can happen in generalized resistance to thyroid hormones. Educational Objective: References: ]]
Approved	Approved::Yes
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