Case Presentation: A 37-year-old female with no significant past medical history presented to emergency room with complaint of palpitation, diarrhea, and heat intolerance. She was five months postpartum. She also complained of unintentional weight loss of 20lb after delivery. She denied fever, chest pain, abdominal pain, or sick contact. General examination including thyroid gland was unremarkable. Thyroid function test showed TSH < 0.005 mIU/ml (Normal 0.5-5) and free T4- 3.33 ng/dl (Normal: 0.8-1.8). Differentials including grave’s disease, Hashimoto thyroiditis and postpartum thyroiditis were considered. She was admitted under observation. She was not started on anti-thyroid mediation at that time, and she was discharged home and recommendation to follow with PCP. Repeat TSH in six-week showed TSH 0.011 mIU/ml and free T4 0.97 ng/dl. Her symptoms were improved. TSH after next 6-week showed normal TSH and free T4. Two months after the last visit she complained of irregular menstrual cycles, weight gain, cold intolerance, and constipation. She denied fever, sick contact, or new medication. Examination was unremarkable. Urine pregnancy test was negative. Thyroid function test showed TSH 8.2 mIU/ml and free T4 0.84 ng/dl. It was thought to be hypothyroid stage of postpartum thyroiditis and she was counselled and sent without medication. After six weeks her symptoms resolved and TSH was 2.5 mIU/ml and free T4 1.17 ng/dl. She followed to the clinic after a year, and she never experienced those symptoms.

Discussion: Postpartum thyroiditis is painless thyroiditis that occurs within a year after delivery. The clinical course consists of thyrotoxic phase, followed by hypothyroid phase and recovery phase. Some patients may develop persistent hypothyroid state and require long term medical therapy. It is believed to be autoimmune in nature associated with presence of antibodies to thyroid peroxidase (TPO) and is characterized by lymphocytic infiltration of the thyroid gland. This should be distinguished from Grave’s disease and Hashimoto thyroiditis. Thyroid blood flow with ultrasound and measurement of anti-TSH receptor antibody is helpful in differentiating it from Grave’s disease. Anti-thyroid medications are not effective, but beta blockers like propranolol can be administered for adrenergic symptoms in the thyrotoxic phase. Levothyroxine is recommended for symptomatic hypothyroid phase. Monitoring thyroid function test is recommended in next pregnancy, delivery and postpartum.

Conclusions: Postpartum thyroiditis can occur within a year of delivery, miscarriage, or medical abortion. It has thyrotoxic, hypothyroid and recovery phase. Antithyroid medication should be avoided in the hyperthyroid phase, beta blockers can treat adrenergic symptoms. In the hypothyroid phase treatment is only necessary if patient has signs and symptoms of hypothyroidism or permanent hypothyroidism. Thyroid function should be closely monitored in next pregnancy, delivery and postpartum.