Question 1

Q: A 30-year-old man develops an increase in shoe size with coarse facies and large hands. IGF1 is elevated. What is the investigation of choice?

Failure to suppress GH by OGTT. ***Failure to suppress GH by OGTT*** - This is the **gold standard dynamic test** for confirming acromegaly, as it proves autonomous and unregulated **Growth Hormone (GH)** secretion [1]. - In healthy individuals, glucose load suppresses GH levels (typically to <1 ng/mL), but this suppression fails in patients with GH-secreting tumors [1]. *IGF-1 levels* - While highly sensitive for screening and monitoring, elevated **Insulin-like Growth Factor 1 (IGF-1)** levels alone are not definitive for diagnosis [2]. - IGF-1 levels must be confirmed with a dynamic test because they can be influenced by other factors like malnutrition or chronic liver failure [2]. *Failure to suppress IGF-1 by OGTT* - The definitive OGTT suppression test measures the suppression of **GH**, not IGF-1; IGF-1 reflects integrated GH production [1]. - While IGF-1 levels are used for diagnosis and monitoring, measuring its failure to suppress during OGTT is not the primary definition of diagnostic test failure. *GH levels* - A single random measurement of **Growth Hormone (GH)** is unreliable for diagnosis because GH is secreted in a highly pulsatile manner [1]. - Dynamic testing, such as the **Oral Glucose Tolerance Test (OGTT)**, is mandatory to confirm the pathological non-suppressibility of GH [1].

Question

A 30-year-old man develops an increase in shoe size with coarse facies and large hands. IGF1 is elevated. What is the investigation of choice?

Accepted Answer

Failure to suppress GH by OGTT

Answer

Failure to suppress IGF-1 by OGTT

Answer

GH levels

Answer

IGF-1 levels

NEET-PG 2025 — Internal Medicine