Transient vs Permanent Congenital Hypothyroidism: Does Thyroid Volume Tell the Tale?

Area of Science:

• Pediatric Endocrinology
• Diagnostic Imaging
• Neonatal Screening

Background:

• Congenital hypothyroidism (CH) presents as transient or permanent forms.
• Distinguishing between these forms is crucial for appropriate management and prognosis.
• Thyroid volume assessment is a potential diagnostic tool.

Purpose of the Study:

• To evaluate the utility of ultrasound-measured thyroid volume in differentiating transient from permanent congenital hypothyroidism.
• To assess the predictive value of thyroid volume and thyroid-stimulating hormone (TSH) levels.

Main Methods:

• Retrospective analysis of patients with CH and eutopic thyroids (2005-2019).
• Permanent CH defined by persistent levothyroxine need post-age 3; transient CH by successful withdrawal.
• Statistical comparisons included Fisher's Exact tests, t-tests, ROC curve analysis, and classification trees.

Main Results:

• Significant differences in TSH levels and thyroid volume between transient (1.0 ± 0.5 mL) and permanent CH (2.3 ± 2.6 mL).
• Thyroid volumes ranged from 0.3 mL to 2.5 mL in transient CH.
• Combined TSH (≥200 mIU/L) and thyroid volume (≤0.6 mL or ≥2.5 mL) achieved 78.4% sensitivity and 85.7% specificity.

Conclusions:

• Thyroid volumes ≥2.5 mL or ≤0.36 mL were exclusively observed in permanent CH.
• Combining TSH levels and thyroid volume enhances diagnostic accuracy for CH forms.
• This approach may help avoid unnecessary levothyroxine withdrawal trials.