A patient presents with excessive thirst, frequent urination, and fatigue. Laboratory results reveal low levels of antidiuretic hormone. Which endocrine gland is most likely malfunctioning in this scenario?

1. A

   Pineal gland

2. B

   Adrenal cortex

3. C

   Anterior pituitary gland

4. D

   Posterior pituitary gland

Appeared in: RRB Nsg. Superintendent-2026 (Shift -2nd)

Explanation

• The posterior pituitary gland is responsible for storing and releasing antidiuretic hormone (ADH) into the bloodstream.
• A deficiency of ADH, as indicated by the lab results, points directly to a dysfunction in the gland that releases it.
• This deficiency causes Diabetes Insipidus, a condition whose hallmark symptoms are excessive urination (polyuria) and excessive thirst (polydipsia), matching the patient's presentation.
• The fatigue is a secondary symptom resulting from dehydration and disruption of sleep due to frequent urination.

Why Other Options Were Wrong

• Option A: The pineal gland's primary function is the secretion of melatonin, which regulates circadian rhythms (sleep-wake cycles). It has no role in regulating water balance or ADH.
• Option B: The adrenal cortex produces corticosteroids (like cortisol) and mineralocorticoids (like aldosterone). Aldosterone affects sodium and water retention, but it is distinct from ADH and is not the primary hormone for water reabsorption indicated here.
• Option C: The anterior pituitary gland produces a different set of hormones (e.g., GH, TSH, ACTH, prolactin). It does not store or release ADH. While the hypothalamus controls the anterior pituitary, the specific hormone in question (ADH) is handled by the posterior lobe.

Related Visual

• Visual 1: Diagram: An illustration of the hypothalamus and pituitary gland, showing ADH being produced in the hypothalamus and stored/released from the posterior pituitary. This visual would clarify the anatomical and functional relationship.
• Visual 2: Flowchart: A flowchart depicting the pathophysiology of Diabetes Insipidus, starting from 'Low ADH release' and leading to 'Polyuria,' 'Dehydration,' and 'Polydipsia'.

Clinical Relevance

• Nursing practice connection: Use the key finding related to Endocrine Gland Function and Hormonal Imbalance to guide bedside assessment, documentation, and the next nursing action.
• Nurses play a critical role in managing patients with Diabetes Insipidus by meticulously monitoring fluid intake and output, checking daily weights to assess fluid status, and administering hormone replacement therapy like desmopressin.
• Patient safety is paramount. A patient with central Diabetes Insipidus who is unable to drink (e.g., post-surgery, unconscious) is at high risk for life-threatening dehydration and hypernatremia if their fluid losses are not replaced.
• What if? If the patient's lab results showed HIGH levels of ADH along with hyponatremia (low sodium), the malfunctioning gland would still be the posterior pituitary (or an ectopic source), but the condition would be Syndrome of Inappropriate ADH (SIADH), the opposite of Diabetes Insipidus.

How to Approach the Question

• First, identify the key information in the stem: the patient's symptoms (excessive thirst, frequent urination, fatigue) and the crucial lab finding (low levels of antidiuretic hormone).
• Recall the function of antidiuretic hormone (ADH). Its name 'anti-diuretic' means it works against diuresis (urination) by promoting water reabsorption in the kidneys.
• Connect the hormone to its gland. Remember that ADH is produced in the hypothalamus but is stored and released by the posterior pituitary gland.
• Analyze the options. Evaluate each endocrine gland based on the hormones it secretes.
• Eliminate the pineal gland (melatonin), adrenal cortex (corticosteroids, aldosterone), and anterior pituitary (GH, TSH, etc.) as they are not directly involved in ADH release.
• Conclude that a low level of ADH causing symptoms of water loss points to a malfunction of the posterior pituitary gland.

Concept Tested & Keywords

• Concept Tested: Endocrine Gland Function and Hormonal Imbalance
• Stem keywords: excessive thirst, frequent urination, fatigue, low levels of antidiuretic hormone
• Lead-in keywords: most likely malfunctioning
• Clinical cues: The combination of polyuria, polydipsia, and low ADH is the classic triad for Diabetes Insipidus.

Question ID

QIl7rJ3RwVKRUyMKnM4tjQ

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