**Question:** Severe wasting is -

A. Decreased muscle mass
B. Increased muscle mass
C. Impaired glucose tolerance
D. Altered skin pigmentation

**Core Concept:** Wasting refers to a decrease in body mass, particularly muscle mass, due to various underlying pathophysiological processes. Severe wasting presents as a critical condition, often related to malnutrition, disease, or injury.

**Why the Correct Answer is Right:** Option A, "Decreased muscle mass," is the correct answer because severe wasting is characterized by a marked reduction in the overall body weight, particularly affecting skeletal muscles. This can be caused by various factors like malnutrition, disease, trauma, or chronic illness leading to muscle catabolism and loss.

**Why Each Wrong Option is Incorrect:**

Option B, "Increased muscle mass," is incorrect because it contradicts the definition of wasting. While some conditions can lead to muscle hypertrophy (enlargement), severe wasting refers to a generalized loss of body mass, not an increase.

Option C, "Impaired glucose tolerance," is incorrect because impaired glucose tolerance is a condition of impaired ability to utilize glucose, often seen in diabetes or obesity, but it is not directly related to severe wasting.

Option D, "Altered skin pigmentation," is incorrect as it is unrelated to the primary definition of wasting, which pertains to body mass loss, specifically muscle mass. Altered skin pigmentation is usually associated with conditions like vitiligo or melanoderma, not wasting.

**Clinical Pearl:** Severe wasting, when unaddressed, can lead to life-threatening consequences such as malnutrition, muscle weakness, and organ dysfunction. Prompt diagnosis and treatment of the underlying cause are essential for recovery and prevention of long-term complications.

**Correct Answer:** Severe wasting is characterized by a marked reduction in muscle mass, which can be caused by various factors like malnutrition, disease, trauma, or chronic illness leading to muscle catabolism and loss.