Goiter is caused by deficiency of?

Appeared in: IGNOU Post B. SC. Nursing entrance -2021

Explanation

Goiter is an enlargement of the thyroid gland, located in the neck.
Iodine is an essential micronutrient required for the synthesis of thyroid hormones, namely thyroxine (T4) and triiodothyronine (T3).
A deficiency in dietary iodine leads to decreased production of thyroid hormones.
In response, the pituitary gland increases the secretion of Thyroid-Stimulating Hormone (TSH).
Prolonged stimulation by TSH causes the thyroid gland to enlarge (hypertrophy and hyperplasia) in an attempt to increase its capacity to trap iodine, resulting in a goiter.

Option A: Iron deficiency is the primary cause of iron-deficiency anemia, which affects the production of hemoglobin in red blood cells. It does not directly cause goiter.
Option C: Calcium is vital for bone health, nerve transmission, and muscle contraction. Its deficiency leads to conditions like osteoporosis, rickets, and tetany, not goiter.
Option D: Sodium is a key electrolyte for maintaining fluid balance and nerve function. Deficiency (hyponatremia) can cause muscle cramps, nausea, and confusion, but it is not related to thyroid enlargement.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Nutritional Deficiencies and Endocrine Disorders as background academic context rather than a clinical decision trigger.
Nurses play a key role in identifying populations at risk for iodine deficiency, especially in endemic regions, and educating them about using iodized salt.
Assessment for goiter is a simple physical examination skill (palpation of the neck) that can be a first step in diagnosing thyroid disorders.
Patient education is crucial. For a patient diagnosed with iodine deficiency goiter, the nurse should explain the importance of dietary changes and adherence to supplementation if prescribed.

How to Approach the Question

First, identify the key terms in the question: 'Goiter' and 'deficiency'.
Recall the basic anatomy and physiology of the endocrine system. 'Goiter' refers to the enlargement of the thyroid gland.
Think about the primary function of the thyroid gland, which is to produce thyroid hormones.
Access your knowledge about the essential nutrients required for hormone synthesis. Remember that iodine is the fundamental building block for thyroid hormones (T3 and T4).
Connect the dots: A deficiency of the building block (iodine) would impair production, leading the gland to enlarge (goiter) as it tries to compensate.
Evaluate the other options to confirm your answer. Iron is for hemoglobin, calcium for bones, and sodium for fluid balance. None are the primary cause of goiter.

Concept Tested & Keywords

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E6 Medicine Davidson Principles Practice 24e p. 667-669

E6 Parks TextBook of Preventive & Social Medicine part 2 — Subpart A (pp 1-232 of 464) p. 158-160

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