Most fatal complication of measles is
**Core Concept**
Measles is a highly contagious viral infection caused by the measles virus, leading to a systemic inflammatory response and potential complications. The disease primarily affects children and adolescents, with the most severe complications arising from secondary bacterial infections and immunological disturbances.
**Why the Correct Answer is Right**
The most fatal complication of measles is subacute sclerosing panencephalitis (SSPE), a rare but devastating neurological disorder that occurs due to persistent measles virus infection in the central nervous system. SSPE is characterized by a gradual degeneration of brain tissue, leading to severe neurological symptoms, including seizures, muscle weakness, and cognitive decline. This condition typically develops 7-10 years after the initial measles infection, indicating a prolonged viral replication and immune evasion.
**Why Each Wrong Option is Incorrect**
* **Option A:** Measles pneumonia is a significant complication of measles, particularly in immunocompromised individuals and those with pre-existing respiratory conditions. However, it is not the most fatal complication.
* **Option B:** Encephalitis is a rare but serious complication of measles, occurring in approximately 1 in 1000 cases. While it can be fatal, it is not as common or severe as SSPE.
* **Option C:** Blindness and deafness can occur as complications of measles, especially in cases of severe measles pneumonia or SSPE. However, they are not the most fatal complications.
**Clinical Pearl / High-Yield Fact**
The measles virus can remain dormant in the central nervous system for years before causing SSPE, highlighting the importance of measles vaccination in preventing this devastating complication.
**Correct Answer: C. Encephalitis**