Postpartum Thyroiditis

1. See also
   1. Hypothyroidism
   2. Hyperthyroidism
   3. Hashimoto's Thyroiditis
   4. Painless Thyroiditis
2. Definition
   1. Painless Thyroiditis following pregnancy
3. Epidemiology
   1. Occurs in 5-10% of postpartum patients
4. Pathophysiology
   1. Painless Thyroiditis
   2. Similar pathophysiology to Hashimoto's Thyroiditis
   3. Associated with HLA-DRB, HLA-DR4 and HLA-DR5
5. Risk Factors
   1. Antithyroid Peroxidase Antibody positive (25% risk)
      1. Associated with Thyroiditis risk, even if euthyroid
      2. Predicts recurrent Thyroiditis in future pregnancies
   2. Type I Diabetes Mellitus
   3. Postpartum Depression
   4. Family History of autoimmune Thyroiditis
6. Types: Postpartum Thyroiditis
   1. Hypothyroidism (40%)
      1. Occurs within one year of delivery (mean: 6 months)
   2. Hyperthyroidism (30%)
      1. Occurs within 10 months of delivery (mean: 3 months)
      2. Resolves spontaneously within 2-3 months of onset
      3. Asymptomatic in one third of patients
   3. Initial Hyperthyroidism, then Hypothyroidism (25%)
      1. Hyperthyroidism phase: 2-4 months postpartum
      2. Hypothyroidism phase: 4-8 months postpartum
7. Complications: Persistent Hypothyroidism (30-50%)
   1. Hypothyroidism persists or recurs within 9 years
   2. Risk factors for longterm hypothyrodism
      1. Initial Hypothyroidism at onset of thyoriditis
      2. Antithyroid Microsomal Antibody at high titer
      3. ThyroidUltrasound with hypoechogenic pattern
8. Differential Diagnosis
   1. See Painless Thyroiditis
   2. Hashimoto's Thyroiditis
   3. Grave's Disease (very important to differentiate)
9. Labs
   1. Antithyroid Peroxidase Antibody positive (80%)
      1. Similar to Hashimoto's Thyroiditis
   2. Erythrocyte Sedimentation Rate (ESR) normal
      1. Contrast to Hashimoto's Thyroiditis
   3. Thyroid stimulating Antibody negative
      1. Contrast with Grave's Disease
10. Imaging
    1. Radioiodine Uptake
       1. Suppressed uptake (Contrast with Grave's Disease)
       2. Do not perform if Breast Feeding
    2. ThyroidUltrasound with doppler
       1. No increased blood flow (Contrast with Grave's)
11. Management
    1. Hyperthyroidism
       1. Beta Blockers if symptomatic (caution in Lactation)
       2. No effect with Propylthiouracil or Methimazole
       3. Follow TSH and T4 Free
          1. Anticipate resolution within 2-3 months
          2. May be followed by Hypothyroidism (see types above)
    2. Hypothyroidism
       1. Levothyroxine for symptomatic Hypothyroidism
       2. Follow TSH
          1. Anticipate Thyroid normalizing by 6-9 months in 80%
12. Prevention
    1. Screen pregnant women with risk factors (see above)
13. References
    1. Bindra (2006) Am Fam Physician 73(10):1769-76
    2. Stagnaro-Green (2002) J Clin Endocrinol Metab 87:4042-7