Increased glucose tolerance is seen in ?

RRB Nsg. Superintendent-21 July 2019 (Shift-2nd)

Biochemistry & Nutrition

Hard

Appeared in: RRB Nsg. Superintendent-21 July 2019 (Shift-2nd)

Explanation

Increased glucose tolerance is a physiological state where blood glucose is cleared from the blood more rapidly, or rises less than normal, after a glucose challenge. This is often seen as a 'flattened' curve on an Oral Glucose Tolerance Test (OGTT).
Hyperinsulinism involves excessive insulin, which directly drives glucose into cells and suppresses liver glucose production, thus rapidly lowering blood glucose.
Hypopituitarism leads to a deficiency of counter-regulatory hormones like Growth Hormone (GH) and cortisol. The absence of these hormones, which normally oppose insulin, results in increased insulin sensitivity and enhanced glucose clearance.
Hypothyroidism slows the metabolic rate, which includes reducing the speed of glucose absorption from the gut. This blunts the post-meal spike in blood glucose, contributing to a flatter tolerance curve.
Since all three conditions—Hyperinsulinism, Hypopituitarism, and Hypothyroidism—can cause increased glucose tolerance through different mechanisms, the most comprehensive and correct answer is 'All of the above'.

Option A: This option is correct, but it is incomplete. Hypopituitarism is only one of the conditions listed that can cause increased glucose tolerance.
Option B: This option is correct, but it is incomplete. Hyperinsulinism is a primary cause, but the other listed endocrine disorders also lead to this state.
Option C: This option is correct, but it is incomplete. While hypothyroidism contributes to increased glucose tolerance, it is not the only cause among the choices.

Visual 1: Diagram: Oral Glucose Tolerance Test (OGTT) curves. This visual should compare a normal glucose response curve with the significantly flattened curve seen in increased glucose tolerance and the high, prolonged curve seen in diabetes mellitus (decreased tolerance).

Clinical Relevance

Nursing practice connection: Knowing Endocrine causes of increased glucose tolerance and risk of hypoglycemia helps nurses interpret findings accurately and avoid errors in routine assessment, medication administration, and patient teaching.
The primary clinical relevance for nurses is the significant risk of hypoglycemia in patients with these conditions. Recognizing the underlying cause helps in anticipating and managing low blood sugar episodes.
Nurses should educate these patients on the signs and symptoms of hypoglycemia (e.g., shakiness, sweating, confusion, irritability) and the importance of carrying a rapid source of sugar.
What if? If a patient with known hypopituitarism undergoes surgery or develops an infection, the nurse must be extremely vigilant. The body's inability to mount a normal cortisol stress response dramatically increases the risk of severe hypoglycemia and adrenal crisis, which is a medical emergency.

How to Approach the Question

First, define the key term 'increased glucose tolerance'. This is the opposite of what is seen in pre-diabetes or diabetes; it means the body is overly efficient at clearing glucose from the blood, leading to lower-than-normal blood sugar levels after a glucose load.
Next, evaluate each option by considering its primary hormonal effect on blood glucose regulation.
Consider Hypopituitarism: A lack of pituitary hormones like GH and ACTH (which stimulates cortisol) removes the natural opposition to insulin, making insulin more effective and increasing glucose tolerance.
Consider Hyperinsulinism: An excess of insulin will directly and powerfully drive glucose out of the blood, which is the definition of increased glucose tolerance.
Consider Hypothyroidism: A slow metabolism can lead to slower absorption of glucose from the gut, blunting the blood sugar spike and thus flattening the glucose curve.
Recognize that all three options are valid causes. When multiple options are correct, and an 'All of the above' choice is available, it is the most complete and correct answer.

Concept Tested & Keywords

Concept Tested: Endocrine causes of increased glucose tolerance and risk of hypoglycemia.
Stem keywords: Increased glucose tolerance
Lead-in keywords: seen in
Negative lead-in flag: false

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