Hyperthyroidism in Children: IAP Guidelines
Hyperthyroidism: Production and secretion of excess amounts of thyroid hormone from the thyroid gland.
Thyrotoxicosis: The hypermetabolic clinical syndrome which occurs when there are elevated serum levels of T3 and/or T4.
The Indian Academy of Pediatrics (IAP) has released Standard Treatment Guidelines 2022 for Hyperthyroidism in Children. The lead author for these guidelines Hyperthyroidism in Children is Dr. Riaz I along with co-author Dr. Bhanu K Bhakhri and Dr. Shalmi Mehta. The guidelines come Under the Auspices of the IAP Action Plan 2022, and the members of the IAP Standard Treatment Guidelines Committee include Chairperson Remesh Kumar R, IAP Coordinator Vineet Saxena, National Coordinators SS Kamath, Vinod H Ratageri, Member Secretaries Krishna Mohan R, Vishnu Mohan PT and Members Santanu Deb, Surender Singh Bisht, Prashant Kariya, Narmada Ashok, Pawan Kalyan.
Following are the major recommendations of guidelines:
Epidemiology:
Hyperthyroidism accounts for 10–15% of thyroid disorders in children.
Age at presentation—it is less common in children <5 years. Peak incidence is at 10–15 years.
It is more common in girls.
Etiology:
Source:Indian Academy of Pediatric Guidelines
Graves' disease accounts for >95% cases of hyperthyroidism.
It is an autoimmune condition and is caused by a complex interaction of genetic, environmental, and immune factors.
Thyrotropin receptor antibodies (TRAb) stimulate thyroid-stimulating hormone (TSH) receptor and increased thyroid hormone production and release.
A family history of autoimmune thyroid disease may be present.
Clinical Features:
The most common clinical features of hyperthyroidism among children are:
Weight loss
Palpitations
Anterior neck swelling
While older children also commonly present with sleep disturbance, poor scholastic performance, and easy fatigability. Increased stool frequency may be seen commonly in younger children.
Other symptoms are excessive sweating, tremors, hair loss, and headache. The features of ophthalmopathy like lid retraction, scleral injection, and proptosis are reportedly less commonly noticed among children.
To establish hyperthyroidism—mechanism.
Source:Indian Academy of Pediatric Guidelines
Investigations:
TSH Suppressed
FT4/FT3 Raised
To find out the causes of hyperthyroidism
Thyrotropin receptor antibody:
It usually raised in Graves' disease.
It also helps in predicting the risk of relapse after stopping antithyroid drugs.
• Technitium-99m scan for thyroid gland: It shows increased uptake in Graves' disease. This can help differentiate between Graves' disease and Hashimoto's thyroiditis (in early stages, due to release of preformed thyroid hormones, there could be hyperthyroidism; however, there is decreased uptake on the thyroid scan)
Ultrasonography:
Usually diffuse enlargement of the gland is visible
Increased vascularity
Helps in ruling out solitary nodule/multinodular goiter.
Other investigations:
Complete blood count (CBC)
Liver function test (to be done before starting antithyroid drugs)
Fine-needle aspiration cytology (FNAC): This is required only if malignancy is suspected during the evaluation of diffuse goiter or thyroid nodules.
Treatment:
The initial goal of therapy is the control of symptoms and normalization of biochemical parameters.
Definitive therapy is considered among children who fail to produce early and long-standing remission.
Source:Indian Academy of Pediatric Guidelines
The preferred initial therapy for children with variety of etiological causes is antithyroid drugs (ATDs).
Methimazole (MMI) 0.1–1 mg/kg/d or carbimazole 0.5–0.7 mg/kg/d is preferred over propylthiouracil (PTU) among children.
The dose of ATD is titrated with the goal to achieve free T4 and T3 estimation within normal range. Addition of beta-blockers like propranolol, 1–2 mg/kg/d helps in early control of symptoms and their dose can be titrated based upon the reported symptoms.
If remission is not achieved, ATD can be safely continued over 1–2 years of duration after which the definitive therapy, either in form of radioiodine ablation (RIA) or surgery, should be considered. Surgery and RIA are preferred over ATD among hyperthyroid children with toxic nodule or multinodular goiter.
Monitoring and Follow-up:
Free T4 and T3 should be estimated every 4–6 weeks for the initial titration of ATD doses.
Once the euthyroidism is achieved, 3 monthly monitoring is optimal.
The baseline CBCs and liver functions should be checked before the initiation of ATD.
Children should be clinically monitored for potential adverse effects of ATD which are urticarial rash, agranulocytosis, hepatic dysfunction, arthralgia, and other vasculitis associated symptoms which may warrant repeat laboratory testing.
If surgery is chosen as definitive therapy, the calcium and parathyroid hormone (PTH) levels should be closely monitored during and after the perioperative period for timely supplementation with calcium and calcitriol.
After RIA or thyroidectomy, the thyroid status should be monitored with free T4 and TSH levels for guiding the replacement doses.
Outcome:
Some children with milder presentation of Hashitoxicosis show good symptom control over short therapy with only beta-blockers medications. Others may require few months of ATD before achieving complete remission which is usually permanent.
Almost one-third children with Graves' disease achieve complete remission after initial ATD trial and there is a considerable risk of relapse once the ATD is stopped. Hence, families should be provided the options for definitive therapy early in the course of disease.
After RIA or thyroidectomy, children need lifelong hormonal replacement for hypothyroidism.
Reference:
The guidelines can be accessed on the official site of IAP: https://iapindia.org/standard-treatment-guidelines/
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