**Core Concept**
Paraesophageal hiatus hernia, also known as type III hiatal hernia, is a type of hernia where the stomach bulges up into the chest cavity through an opening in the diaphragm. This type of hernia is often associated with complications such as gastric volvulus and incarceration, which can lead to severe symptoms and potentially life-threatening conditions.

**Why the Correct Answer is Right**
The correct answer states that surgery is indicated in all symptomatic cases of paraesophageal hiatus hernia. This is because paraesophageal hernias are at a higher risk of complications due to the stomach's ability to twist or become trapped in the chest cavity. The risk of complications is much higher in symptomatic cases, making surgical intervention the preferred treatment approach. The surgical repair of paraesophageal hernias typically involves a laparoscopic approach to reduce the risk of complications and promote faster recovery.

**Why Each Wrong Option is Incorrect**
**Option B:** While paraesophageal hernias are indeed more complicated due to their higher risk of complications, this option does not directly address the indication for surgery. The correct answer specifically states that surgery is indicated in symptomatic cases, making option B an incomplete explanation.

**Option C:** Paraesophageal hernias are not the most common type of hiatus hernia. The most common type is the sliding hiatus hernia, which occurs when the upper part of the stomach slides up into the chest cavity through the esophageal hiatus.

**Option D:** Hiatus hernias are not common in infants. They are more commonly seen in adults, particularly those over the age of 50.

**Clinical Pearl / High-Yield Fact**
A key point to remember is that paraesophageal hernias often present with severe symptoms such as chest pain, difficulty swallowing, and vomiting, and may require emergency surgical intervention if complications arise. Prompt recognition and treatment of paraesophageal hernias are essential to prevent long-term complications and improve patient outcomes.

**✓ Correct Answer: A. Surgery indicated in all symptomatic cases of paraesophageal**