Acute meningitis in adolescents and young adults is caused by –
**Core Concept**
Acute meningitis is an inflammation of the protective membranes covering the brain and spinal cord, known as the meninges. The most common causes of acute meningitis are bacterial, viral, or fungal infections. In adolescents and young adults, the epidemiology of meningitis is closely related to the immune status and exposure to specific pathogens.
**Why the Correct Answer is Right**
The correct answer is related to the common pathogens responsible for acute meningitis in this age group. In adolescents and young adults, **Neisseria meningitidis** (meningococcus) is a leading cause of bacterial meningitis, particularly in outbreaks or epidemics. This bacterium can cause severe, life-threatening illness.
**Why Each Wrong Option is Incorrect**
**Option A:** This choice is incorrect because, although it may be a cause of meningitis in other age groups or contexts, it is not the most common cause in adolescents and young adults.
**Option B:** Similarly, this option is incorrect as it does not represent the primary pathogen responsible for acute meningitis in the specified demographic.
**Option C:** This choice is also incorrect for the same reason, not being the predominant cause of meningitis in adolescents and young adults.
**Option D:** This is incorrect as, while it may cause meningitis, it is not the most common cause in this particular age group.
**Clinical Pearl / High-Yield Fact**
A key point to remember is that **Neisseria meningitidis** infections can lead to outbreaks, especially in crowded settings like college campuses or military barracks, highlighting the importance of vaccination against this pathogen.
**Correct Answer:** D. Neisseria meningitidis.