Respiratory system infections in HIV is seen with: September 2005
**Core Concept**
The question is testing the association between HIV infection and opportunistic infections in the respiratory system. HIV-infected individuals are prone to various infections due to compromised immune function, particularly those caused by opportunistic pathogens.
**Why the Correct Answer is Right**
In HIV-infected individuals, the compromised immune system increases the susceptibility to opportunistic infections, including those affecting the respiratory system. Pneumocystis jirovecii pneumonia (PCP) is a classic example of such an opportunistic infection, caused by the fungus Pneumocystis jirovecii. This infection is characterized by the inhalation of the spores, which then colonize the alveoli, leading to inflammation and damage to the lung tissue. The pathogenesis of PCP involves the replication of the organism within the lung tissue, leading to the release of inflammatory mediators and the recruitment of immune cells, resulting in symptoms such as cough, dyspnea, and hypoxemia.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not specify a particular opportunistic infection commonly seen in HIV-infected individuals.
**Option B:** This option is incorrect because it is not a specific opportunistic infection associated with HIV.
**Option C:** This option is incorrect because it is not a common respiratory infection in HIV-infected individuals.
**Clinical Pearl / High-Yield Fact**
PCP is a classic example of an opportunistic infection in HIV-infected individuals and is often seen in those with a CD4 count below 200 cells/mm3. Early diagnosis and treatment are critical to prevent complications and mortality.
**Correct Answer: C. Pneumocystis jirovecii pneumonia (PCP)**