**Core Concept**
A pseudo-aneurysm, also known as a false aneurysm, is a leakage of arterial blood from an artery into the surrounding tissue without fully disrupting the integrity of the arterial wall. This condition is often associated with trauma, infection, or iatrogenic causes.

**Why the Correct Answer is Right**
Pseudo-aneurysms in drug abusers are commonly seen in the context of intravenous (IV) drug use, particularly with the use of non-sterile needles or contaminated substances. When a needle pierces the arterial wall, it can cause a disruption in the blood vessel, leading to a leakage of blood into the surrounding tissue. This is known as a traumatic pseudo-aneurysm. The repeated use of non-sterile needles or equipment can increase the risk of infection, which can further compromise the integrity of the blood vessel and contribute to the formation of a pseudo-aneurysm.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is not relevant to the formation of pseudo-aneurysms in drug abusers.
* **Option B:** While infection can contribute to the formation of pseudo-aneurysms, it is not the primary cause in this context.
* **Option D:** This option is not related to the formation of pseudo-aneurysms in drug abusers.

**Clinical Pearl / High-Yield Fact**
Drug abusers should be counseled on the importance of using sterile needles and equipment to prevent the formation of pseudo-aneurysms and other infections.

**Correct Answer:** C