9/13/2013

9/13/2013

Answers:

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

The half life of T3 is 24hrs, the half life of T4 is 7dys. This is why patients on L-thyroxine can be dosed daily and that skipping a few days of therapy if the patient cannot take PO is not life threatening.

Name two common drugs that limit T4-->T3 conversion.

Medications that inhibit T4-->T3 conversion include amiodarone, glucocorticoids, propylthiouracil, propranolol, and iodine.

MC Questions:

A patient with a high TSH, low T4 and normal T3 likely has ---? A patient with low TSH, low T4 and low T3 likely has---?
A) Subclinical hypothyroidism, Central hypothyroidism 
B) Primary Hypothyroidism; Central hypothyroidism 
C) Subclinical hypothyroidism; Primary hypothyroidism 
D) T3 toxicosis, drug induced hypothyroidism 
E) Hyperthyroidism; Sick Euthyroid

Free Response Question:
What is the rate of "incidentalomas" found on high resolution thyroid ultrasounds in the general population?

Quick Facts:
Thyroid Physical Exam
-3 maneuvers to examine thyroid    
-pt should slightly flex neck to relax SCM    
-observe thyroid while pt swallows    
-palpate from behind while pt swallows