Examkin

Soru

Zorluk: KolayPediatric Endocrine Disorders

A 12-year-old girl is brought to the clinic by her parents due to fatigue, poor school performance, and constipation over the past 6 months. Her parents also note that she frequently complains of feeling cold, even in warm weather. Growth chart review shows her height has dropped from the 50th percentile two years ago to the 15th percentile currently, while her weight has increased from the 50th to the 75th percentile. Physical examination reveals dry skin, a diffusely enlarged and non-tender thyroid gland (goiter), and delayed relaxation of the deep tendon reflexes. Laboratory studies show a low serum free T4 level and a markedly elevated TSH level. Which of the following is the most likely underlying mechanism of this patient's condition?

  1. Cell-mediated autoimmune destruction of the thyroid glandCevap
  2. B
    Inadequate secretion of thyrotropin from the anterior pituitary gland
  3. C
    Antibody-mediated stimulation of thyrotropin receptors
  4. D
    Normal physiologic variation in growth and pubertal timing
  5. E
    Peripheral tissue resistance to circulating thyroid hormone

Cevap

Cell-mediated autoimmune destruction of the thyroid gland
The patient's clinical presentation (fatigue, cold intolerance, constipation, declining linear growth velocity, and a goiter) is classic for hypothyroidism. The laboratory findings of a low free T4 and a markedly elevated TSH confirm primary hypothyroidism (failure at the level of the thyroid gland). In iodine-sufficient regions, the most common cause of acquired primary hypothyroidism and goiter in children and adolescents is Hashimoto thyroiditis (chronic lymphocytic thyroiditis). The underlying mechanism is cell-mediated autoimmune destruction of the thyroid gland, often accompanied by anti-thyroid peroxidase (anti-TPO) and anti-thyroglobulin antibodies.

Adım Adım Çözüm

1
Identify the clinical syndrome from the history and physical examination.
The patient has fatigue, cold intolerance, constipation, poor linear growth, weight gain, a goiter, and delayed reflex relaxation, which collectively point to hypothyroidism.
Recognizing the constellation of hypothyroid symptoms is the first step in localizing the endocrine dysfunction.
2
Interpret the laboratory findings to determine the etiology.
A low free T4 with a markedly elevated TSH indicates primary hypothyroidism.
The elevated TSH demonstrates that the anterior pituitary is responding appropriately to a lack of thyroid hormone by increasing TSH secretion, meaning the defect lies within the thyroid gland itself.
3
Correlate the primary hypothyroidism with the most common cause in a pediatric patient.
The most common cause of acquired primary hypothyroidism and goiter in children and adolescents in iodine-sufficient regions is Hashimoto thyroiditis, an autoimmune disease.
Understanding disease epidemiology and pathophysiology leads directly to the mechanism of autoimmune destruction.

Anahtar Kavram

Hashimoto thyroiditis is the most common cause of acquired primary hypothyroidism in children, characterized by autoimmune destruction of the thyroid gland, low free T4, and an elevated TSH.
Bu soruyu puanla

Konular

Pediatric Endocrine Disorders

Bu konudan daha fazla soru