1. Case 1 Name: Gender: Female Age: 30 Yeas Marital State: Married + 2 Residence: Alexandria – Egypt Occupation: Housewife Special Habits: Nil (no smoking) Complaints:  Loss of weight  Irritable  Uncomfortable with summer weather Examination: Pulse: 130 Blood pressure: 155/95 Palm sweaty  Fine tremors of the fingers when her arms are stretched  No eye signs  Thyroid gland enlarged – No nodules History On contraceptive pills containing estrogen Investigations: Thyroid function tests Further investigations: Diagnosis: Treatment:

2. Clinical Biochemistry Lab Unit of Endocrinal Investigations Thyroid Function Tests Name of Patient : Case 1 DOB: 31/10/1983 Gender: Female Date of investigation:: 23/7/2012 Sample type: Blood Sample Number: 91024 Analysis Result Reference Range TSH 0.1 mIU/L 0.3 – 0.5 Free T4 20 pmol/L 10-27 Total T4 160 nmol/L 70-150 Free T3 20 pmol/L 3- 9 Total T3 6 nmol/L 1.2-2.8

3. Case 2 Gender: Male Age: 38 Yeas Marital State: Married + 3 Occupation: Engineer He came to the outpatient clinic for follow up of his treatment He was already diagnosed as Graves disease Started treatment 3 months ago Investigations: Thyroid function tests Comments: ?? Recommendations: ??

4. Clinical Biochemistry Lab Unit of Endocrinal Investigations Thyroid Function Tests Name of Patient : Case 2 DOB: 12/11/1975 Gender: Male Date of investigation:: 2/4/2013 Sample type: Blood Sample Number: 101123 Analysis Result Reference Range TSH less than 0.1 mIU/L 0.3 – 0.5 Free T4 5 pmol/L 10 - 27 Total T4 100 nmol/L 70-150 Free T3 2.9 pmol/L 3- 9 Total T3 0.9 nmol/L 1.2-2.8

5. Case 3 Name : Gender: Female Age: 26 Years Marital State: Single Occupation: Student Residence: Al-Wahat Al-Kharja- EGYPT Special Habits: Nil Complaints: Tired and feeling low all the time Gaining weight Discomfort in her neck Examination: Pulse: 55 BP: 108/65 Palm dry Thyroid examination: Goiter Investigations: Thyroid function tests Further investigations: ?? Diagnosis: ?? Treatment:?? Follow up:

6. Clinical Biochemistry Lab Unit of Endocrinal Investigations Thyroid Function Tests Name of Patient : Case 3 DOB: 12/11/1984 Gender: Female Date of investigation:: 24/9/2010 Sample type: Blood Sample Number: 80656 Analysis Result Reference Range TSH 48 mIU/L 0.3 – 0.5 Free T4 8 pmol/L 10 - 27 Total T4 56 nmol/L 70-150 Free T3 6 pmol/L 3- 9 Total T3 1.9 nmol/L 1.2-2.8

7. In individuals with iodide deficiency, what is the cause of the thyroid enlargement ?? (Goiter Formation)

8. Answer: Elevation of TSH is the mechanism for goiter formation Decreased thyroid hormone levels reduce feedback inhibition of TSH secretion by the pituitary. TSH secretion is increased. TSH acts as a growth factor for the thyroid gland increasing its mass Increase its capacity to synthesize thyroid hormones

9. Case 4: A 25-year old female asked her family doctor for a tretment her constant fatigue, lethargy & depression. She was small in stature & had previously been diagnosed with attention-deficit disorder.(recorded in her medical file). On physical examination She was found to have an enlarged thyroid gland (goiter). HOWEVER!! Blood tests revealed elevated levels of T3, T4 and TSH, yet she did not exhibit typical symptoms of hyperthyroidism. How can you explain this case???

10. WHAT DO YOU THINK???  Thyroid hormone overproduction because of a thyroid gland tumor ? Or  Hypersecretion of TSH because of a pituitary tumor? Or  Genetic alteration in the thyroid receptor reducing its ability to bind thyroid hormone? Or  Mutation in the TSH receptor in the thyroid gland reducing its ability to bind TSH ? Or  Iodide deficiency in the diet ?

11. Answer is C: The patient exhibits symptoms of hypothyroidism including goiter …etc, yet thyroid hormone levels are elevated. This pattern can only be explained by resistance of target cells to thyroid hormone, for example, a mutation of the receptor decreasing its binding affinity for hormone N.B. Iodide deficiency would lead to goiter but not increased hormone levels