Introduction

• Mild elevation in thyroid stimulating hormone (TSH <10U/l), is commonly seen and in many cases will often improve without treatment.

                - This is particularly common in children and adolescents with a BMI in the overweight or obese range, and will improve with improvement in BMI

                - These children do not require referral, but should have repeat thyroid function tests in 3 months

• Children with mildly elevated TSH should have anti-thyroid peroxidase (anti-TPO) and anti-thyroglobulin antibodies checked

                - Mild elevation in these antibodies is common, and can occur following a viral infection

                - Very elevated anti-TPO antibodies suggests Hashimoto’s thyroiditis

                - Many cases of subacute thyroiditis or Hashimoto’s thyroiditis will resolve without treatment

• Those with positive anti-thyroid antibodies and normal or mildly elevated TSH do not require referral, but should be monitored with surveillance thyroid function tests in 3 months

When to refer

• If TSH >20U/l and/or fT4 below the normal lab reference range;
  • Please also phone to discuss with endocrinologist / fellow on call as treatment before endocrine OPD review likely warranted
• TSH between 10 and 20U/l (even if fT4 normal) on two occasions
  • Repeat test in ~6 weeks to ensure no significant change pre outpatient review (include anti-thyroid peroxidase (TPO) and anti-thyroglobulin antibodies on repeat test if not yet done)
  • For children <2 years of age, consider earlier retesting and discussion with endocrinology team as there is a lower threshold for earlier treatment

Please note: Children with possible central / pituitary cause for hypothyroidism may not be able to raise their TSH level and so an isolated low fT4 with ‘normal’ TSH in children with a relevant history (eg structural brain abnormality / lesion) is sufficient cause for concern.

Initial work up

• TSH and T4 (and previous thyroid function tests if available)
• Anti-thyroid peroxidase and anti-thyroglobulin antibodies (if done)
• Please note: routine ultrasound of children with hypothyroidism is not required

Referral information needed

• Clinical history / reason for testing
• Copies of reports of abnormal thyroid function tests and autoantibody testing as above
• Current height and weight (including date of assessment)
• Relevant family / personal history of thyroid disease or other autoimmunity

Contact information

• For clinical advice, the endocrinology fellow or endocrinologist on call can be contacted through the hospital switch board (03) 9345 5522
• Outpatient booking enquiry information (03) 9345 6180
  

Author

Guideline developed by RCH Endocrinology Department