Tabes dorsalis is seen in which stage of syphilis –
**Core Concept**
Tabes dorsalis is a complication of **syphilis**, specifically affecting the **dorsal columns** of the spinal cord. It is characterized by **neurological deficits**, including loss of proprioception and vibration sense. This condition is a result of **tertiary syphilis**.
**Why the Correct Answer is Right**
Tabes dorsalis occurs in the tertiary stage of syphilis, which can manifest decades after the initial infection. During this stage, the **spirochaete Treponema pallidum** causes **inflammatory damage** to the dorsal columns, leading to the characteristic symptoms. The **delayed onset** and **progressive nature** of tabes dorsalis are hallmarks of tertiary syphilis.
**Why Each Wrong Option is Incorrect**
**Option A:** Primary syphilis is the initial stage, characterized by a **chancre** at the site of infection, and does not involve neurological complications like tabes dorsalis.
**Option B:** Secondary syphilis involves **systemic symptoms** and **rash**, but does not typically involve the central nervous system to the extent of causing tabes dorsalis.
**Option D:** There is no "quaternary" stage of syphilis recognized in medical literature.
**Clinical Pearl / High-Yield Fact**
Tabes dorsalis is a classic example of a **late manifestation** of syphilis, emphasizing the importance of **long-term follow-up** and **screening** for syphilis in high-risk populations.
**Correct Answer:** D is not provided, the stages provided are primary, secondary, latent, and tertiary, so the correct stage is tertiary, assuming D is the correct stage which would be tertiary in a standard classification. **Correct Answer: D. Tertiary**