Due to the lack or low level of which hormone does a young child suffer from cretinism?

ESIC Nursing Officer 2016 (shift-1)

Child Health Nursing (Pediatrics)

Easy

Appeared in: ESIC Nursing Officer 2016 (shift-1)

Explanation

Cretinism, now more commonly called congenital hypothyroidism, results from a deficiency of thyroid hormones during fetal life or infancy.
Tetraiodothyronine (T4 or thyroxine) is the primary thyroid hormone essential for normal brain development, myelination, and skeletal growth.
Its absence or low levels lead to severe, irreversible intellectual disability and stunted physical growth if not treated promptly after birth.

Option A: Calcitonin is produced by the thyroid gland but its primary function is to regulate calcium and phosphate metabolism. Its deficiency does not cause the developmental defects characteristic of cretinism.
Option C: Hydrocortisone (cortisol) is a glucocorticoid produced by the adrenal cortex. Its deficiency causes adrenal insufficiency (Addison's disease), which presents with symptoms like fatigue, weight loss, and low blood pressure.
Option D: Aldosterone is a mineralocorticoid produced by the adrenal cortex that regulates salt and water balance. Its deficiency leads to electrolyte disturbances like hyponatremia and hyperkalemia.

Visual 1: Diagram: The Hypothalamic-Pituitary-Thyroid (HPT) axis, showing how TRH from the hypothalamus stimulates TSH from the pituitary, which in turn stimulates the thyroid to produce T3 and T4.
Visual 2: Infographic: Comparison of an infant with signs of untreated congenital hypothyroidism (e.g., puffy face, macroglossia, umbilical hernia, dull expression) versus a healthy infant.
Visual 3: Flowchart: Newborn screening process, from heel-prick test to confirmatory diagnosis and initiation of treatment for congenital hypothyroidism.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Hormonal basis of Cretinism (Congenital Hypothyroidism) as background academic context rather than a clinical decision trigger.
Early detection through mandatory newborn screening (heel-prick test for TSH/T4) is one of the most successful public health interventions, as it allows for timely treatment that prevents the devastating and irreversible neurological damage of congenital hypothyroidism.
Nurses are pivotal in educating parents about the lifelong nature of hormone replacement therapy, the correct administration of levothyroxine (e.g., crushing the tablet, giving on an empty stomach), and the critical importance of adhering to regular follow-up appointments and blood tests.
What if? If a newborn screening shows a high TSH but a normal T4, this indicates subclinical hypothyroidism. While immediate treatment might not always be started, it requires close monitoring and follow-up as it can progress to overt hypothyroidism, still posing a risk to neurodevelopment.

How to Approach the Question

First, identify the key term in the question: 'cretinism'.
Recall or deduce that cretinism is the historical term for congenital hypothyroidism, a condition present from birth.
Connect the term 'hypothyroidism' to the thyroid gland and its primary hormones.
Evaluate the options provided. Tetraiodothyronine (T4) is a primary thyroid hormone. Calcitonin is also from the thyroid but has a different function (calcium regulation). Hydrocortisone and Aldosterone are from the adrenal glands, ruling them out.
Conclude that the lack of tetraiodothyronine, the main hormone for metabolic rate and development, is the cause of cretinism.

Concept Tested & Keywords

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