**Question:** A person has received complete immunization against tetanus 10 years ago. Now he presents with a clean wound without any lacerations from an injury sustained 2.5 hours ago. He should now be given?

**Core Concept:** Tetanus is a neurotoxic disease caused by the bacteria Clostridium tetani. When a clean wound is contaminated with Clostridium tetani spores, they can germinate and produce toxins, leading to tetanus symptoms. Tetanus immunization provides immunity against tetanus toxins.

**Why the Correct Answer is Right:** The individual has received complete tetanus immunization 10 years ago, which induces an immune response against tetanus toxins. As a result, the body has developed immunity to tetanus toxins. When the wound is clean without any lacerations, there is a low likelihood of Clostridium tetani spores entering the body, but since the wound is contaminated with spores 2.5 hours ago, the toxin production is likely to have occurred. Therefore, the administration of tetanus toxoid (tetanus immunoglobulin) is necessary to neutralize the toxins before they cause clinical symptoms.

**Why Each Wrong Option is Incorrect:**

A. This option is incorrect because tetanus toxoid is not required for clean wounds without any history of tetanus vaccination. In this case, the individual has already received complete tetanus immunization, rendering this option irrelevant.

B. Although the wound has been contaminated, the toxin production might not have occurred yet due to the relatively short duration (2.5 hours) since wound contamination. The administration of tetanus toxoid is essential for toxin neutralization.

C. While the wound is contaminated, the toxin production can occur even after a clean wound due to the presence of tetanus toxin-producing bacteria. However, the main focus of this question is that the individual has received complete tetanus immunization, rendering this option incorrect.

D. This option is incorrect because tetanus toxoid is not a treatment for established tetanus. The individual has already received complete tetanus immunization, so this option is not relevant.

**Clinical Pearl:** Timely tetanus toxoid administration is crucial for neutralizing the tetanus toxin before it causes clinical symptoms. In this case, the individual has received complete tetanus immunization, making it essential to administer tetanus toxoid (tetanus immunoglobulin) within 48 hours of wound contamination to neutralize the toxin before it causes clinical symptoms. Failure to do so can lead to tetanus infection, which is characterized by muscle spasms, seizures, and severe respiratory distress.