Hashimoto’s thyroiditis is the leading cause of hypothyroidism in children and adolescents, characterized by chronic lymphocytic infiltration of the thyroid gland, which results in progressive thyroid dysfunction ¹. In iodine-deficient regions, it is also the most common cause of acquired hypothyroidism and goitre in this population ². Globally, however, iodine deficiency remains the primary cause of hypothyroidism ³. Clinical presentation can vary, including asymptomatic goitre, typical hypothyroid symptoms, and less commonly, signs of hyperthyroidism 2. The pathophysiology involves the production of antithyroid antibodies that target thyroid tissue, leading to fibrosis. Diagnosing HT can be delayed as the clinical course progresses slowly. Typical laboratory findings include low free thyroxine (FT4), elevated thyroid-stimulating hormone (TSH), and high levels of antithyroid peroxidase (TPO) antibodies. In some cases, hyperthyroid-like symptoms and lab results may appear early due to intermittent thyroid cell death. The first-line treatment is oral levothyroxine sodium ³. Untreated hypothyroidism carries risks such as hypertension, cardiovascular disease, heart failure, hypercholesterolemia, and, in pregnant women, increased risk of birth defects. Myxedema, a rare but potentially life-threatening complication, can also occur ⁴. This case report highlights the importance of a multidisciplinary approach in the early diagnosis and management of paediatric Hashimoto’s thyroiditis.

In children and teenagers, the most frequent cause of autoimmune thyroid disease is Hashimoto's thyroiditis (HT). T cells react with thyroid antigens and secrete inflammatory cytokines, which are crucial in the pathophysiology of illness. Thyroid peroxidase, thyroglobulin, and the TSH receptor blocking antibodies are present in patients with HT thyroiditis. Thyroid follicular cell destruction brought on by T cells is the primary cause of these autoantibodies. It causes persistent inflammation by attacking the thyroid gland with the body's immune system. ⁵ In this case, the patient displayed symptoms like fever, cough, cold, vomiting, and headache that are frequently linked to viral infections. Ergul AB, Dursun et al says that measuring antithyroid antibodies ideally, TPO Ab will confirm that hypothyroidism is caused by HT. ⁶ The thyroid gland exhibits typical ultrasonography abnormalities in the HT patient, including scattered hypo and hyperechogenicity. Our patient was diagnosed with hypothyroidism (HT) due to greater titers of antithyroid antibodies and with bilateral cervical lymphadenitis was verified by a neck ultrasonography. ⁷

The first instance of this type was reported by Papi and Ezzat ⁸. The patient was a male 59-year-old who had symptoms compatible with SAT. Three months after presenting with high titers of antithyroid antibodies, which suggested an autoimmune thyroid illness, the patient became obviously hypothyroid. Similarly, Minciullo et al ⁹ reported a case of a young female with ultrasonographic characteristics and an HLA genotype favouring Hashimoto thyroiditis who acquired hypothyroidism years later. The main theory in each of these situations was that an infection that served as a trigger created autoimmunity toward the thyroid gland, which in turn caused autoimmune thyroid disease ⁹ Our patient experienced a fever, cough, cold and swelling of neck. Lymphadenopathy was present to the patient one month ago. These features made to diagnose autoimmune thyroiditis. Benvenga et al.'s sufficient evidence on the homologies between bacteria and thyroid antigens support the idea that autoimmune thyroid disorders can be brought on by viral or bacterial infections ¹⁰. It has also been established that a number of susceptibility genes for autoimmune thyroid illness have a role in the main pathways that underlie this organ-specific autoimmunity ¹⁰. The goal of the treatment plan was to reduce symptoms and employ thyroxine replacement therapy to treat the underlying thyroid problem. The patient showed stability in vital signs and no acute distress, indicating a good response to the medication. Timely diagnosis and treatment with levothyroxine are critical in preventing developmental delays, growth retardation, and other metabolic disturbances associated with hypothyroidism ¹¹. Early intervention ensures better cognitive outcomes and normal growth trajectories.

This case highlights the need to consider Hashimoto’s thyroiditis in paediatric patients who present with non-specific symptoms and normal developmental milestones. Timely and accurate management of Hashimoto’s thyroiditis through early diagnosis is crucial to ensuring optimal growth and development in children while preventing long-term complications. Future guidelines, especially in regions with a high prevalence of autoimmune thyroid disorders, should recommend routine thyroid function screening for children displaying vague symptoms such as fatigue, neck swelling, or unexplained weight changes. Ongoing monitoring of thyroid function is also vital to adjust treatment dosages as required. Additionally, further research is needed to explore the role of infections as potential triggers for autoimmune thyroiditis and to better understand the genetic and environmental factors influencing the development of HT in young populations. Insights into these factors could lead to earlier detection and more effective prevention strategies, ultimately improving patient outcomes.