Management of a 9-Year-Old with Hypothyroidism on Levothyroxine with TSH 2.2
Current Thyroid Status Assessment
The TSH of 2.2 mIU/L indicates adequate thyroid hormone replacement, and no dose adjustment is needed. 1, 2
- This TSH value falls well within the normal reference range of 0.45-4.5 mIU/L for pediatric patients 1
- The target for pediatric hypothyroidism treatment is to normalize serum TSH levels, which has been achieved 3
- In pediatric patients, the general aim of therapy is to normalize the serum TSH level, and this patient has met that goal 3
Critical Monitoring Considerations for This Pediatric Patient
Continue current levothyroxine dose and monitor TSH every 3-12 months following dosage stabilization. 3
Pediatric-Specific Monitoring Protocol
- Monitor TSH and total or free-T4 every 3 to 12 months following dosage stabilization until growth is completed 3
- Perform routine clinical examination, including assessment of development, mental and physical growth, and bone maturation at regular intervals 3
- Poor compliance or abnormal values may necessitate more frequent monitoring 3
Special Considerations for ADHD Comorbidity
The presence of ADHD does not change thyroid management when TSH is adequately controlled. 4, 5
- Maternal hypothyroidism is associated with increased ADHD risk in offspring, but this association is not mitigated by levothyroxine treatment and is unexplained by thyroid hormone levels 4
- In children with ADHD who do not have resistance to thyroid hormone (RTH), thyroid hormone treatment has no effect on ADHD symptoms or may be detrimental 5
- Supraphysiological doses of thyroid hormone are not beneficial for ADHD symptoms in children without RTH and may worsen impulsivity 5
Critical Pitfalls to Avoid
Do not increase levothyroxine dose to achieve a lower TSH, as this risks iatrogenic hyperthyroidism. 1, 6
- Overtreatment in pediatric patients with congenital hypothyroidism is associated with attention problems and ADHD-like symptoms 6
- Early overtreatment (particularly in the first 1-3 months postnatally) is associated with permanent ADHD symptoms at ages 6 and 11 years 6
- Overtreatment increases risk for craniosynostosis and acceleration of bone age in pediatric patients 3
- Approximately 14-21% of treated patients develop subclinical hyperthyroidism, which carries significant risks 1
Do not attribute behavioral symptoms to thyroid dysfunction when TSH is normal. 4, 5
- The conduct disorder and ADHD symptoms are unlikely to be related to thyroid status when TSH is adequately controlled 4
- Thyroid hormone treatment does not improve ADHD symptoms in children with normal thyroid function 5
Ongoing Management Algorithm
When to Continue Current Dose
- TSH remains 0.5-4.5 mIU/L 1, 3
- Normal growth and development continue 3
- No symptoms of hypo- or hyperthyroidism 3
When to Adjust Dose
- TSH rises above 4.5 mIU/L on repeat testing: increase levothyroxine by 12.5-25 mcg 1
- TSH falls below 0.45 mIU/L: decrease levothyroxine by 12.5-25 mcg 1
- Failure of serum T4 to increase into upper half of normal range within 2 weeks of treatment initiation 3
- Failure of serum TSH to decrease below 20 IU/L within 4 weeks of treatment initiation 3
Red Flags Requiring Immediate Reassessment
- Development of symptoms suggesting overtreatment: hyperactivity, irritability, sleep disturbances, tremors 3, 6
- Growth acceleration or bone age advancement 3
- Cardiovascular symptoms: rapid heartbeat, chest pain 3
Special Pediatric Considerations
Assess compliance before making any dose changes. 3, 7
- Poor compliance is the most common cause of TSH elevation in treated patients 7
- Instruct parents to administer levothyroxine as a single dose on an empty stomach, one-half to one hour before breakfast with a full glass of water 3
- Avoid administration within 4 hours of iron, calcium supplements, or antacids 3
Monitor for developmental milestones and educational performance. 3, 6