**Question:** Major symptoms of hypernatremia are

A. Dry mouth
B. Fatigue
C. Confusion
D. Delirium

**Core Concept:**
Hypernatremia is a condition characterized by abnormally high sodium levels in the blood, typically due to excessive intake of sodium or inadequate intake of water. Symptoms may arise as a result of the disruption of osmoregulation and the subsequent effects on the brain and overall body functions.

**Why the Correct Answer is Right:**
Major symptoms of hypernatremia include Dry Mouth (Option D), Fatigue, Confusion, and Delirium. These symptoms are related to the consequences of increased sodium levels in the blood on osmoregulation, cellular volume, and brain functions.

1. Dry Mouth (Option D): Hypernatremia can lead to a reduced production of saliva due to osmotic effects on the salivary glands, leading to a dry mouth.
2. Fatigue (Option B): Increased extracellular sodium concentrations can negatively impact cellular energy production by impairing the Krebs cycle and decreasing adenosine triphosphate (ATP) production. This results in fatigue.
3. Confusion (Option C): Hypernatremia can cause brain swelling, impaired neuronal function, and ultimately lead to confusion due to the disruption of osmoregulation and cellular volume.
4. Delirium (Option D): Severe hypernatremia can cause more severe brain swelling, leading to altered mental status and delirium.

**Why Each Wrong Option is Incorrect:**
A. Fatigue is not listed as a major symptom of hypernatremia but rather a result of cellular energy production impairment (Option B).
5. Delirium is not listed as the first symptom but rather a severe form of confusion or altered mental status (Option D).
6. Confusion is less severe than delirium and is not listed as the primary symptom (Option C).

**Clinical Pearl:**
Hypernatremia should be considered when evaluating patients with symptoms like fatigue, confusion, or delirium, and appropriate interventions may be necessary to correct the electrolyte imbalance and mitigate its consequences.