9/12/2013

9/12/2013

Answers:

When the thyroid gland enlarges due to illness, it most often extends in what direction?
A) Superior and Anteriorly 
B) Inferior and Anteriorly
C) Superior and Posteriorly 
D) Inferior and Posteriorly 
E) Laterally

Superior extension is blocked by the sternothyroid muscle.

What is are the two major roles of thyroid peroxidase in the production of thyroid hormone?

TPO is a catalyst for both the oxidation of iodide and iodination of tyrosyl residues in thyroglobulin as well as the linking of pairs of iodotyrosine molecules within thyroglobulin to form T4 and T3.

MC Questions:

The half life of T4 is --- whereas the halflife of T3 is ---.
A) 7hrs, 7dys 
B) 7dys,24hrs 
C) 24hrs, 12hrs 
D) 1 wk, 3 dys 
E) 12 hrs, 2 hrs

Free Response Question:
Name two common drugs that limit T4-->T3 conversion.

Quick Facts:
Thyroid Nodules
-High res US show nodules in 19-67% of general population i.e. incidentalomas.
-5-15% of nodules are malignant.
Clinical Findings
-incidental nodules >1cm should be investigated.
-palpable has same malignancy as nonpalpable.
-investigate <1cm if:    
-suspicious US findings    
-adult younger than 30    
-older than 60    
-hx of head/neck irradiation    
-hx of thyroid cancer (cowden’s syndrome)         
-multiple hamartomas        
-increased risk of cancer