Question

A known case of AIDS with productive cough and fever was found to have consolidation in the right infrascapular area. X-Ray chest showed right lower lobe consolidation with CD4 count of 55 per microlitre. What is the most common cause of this?

• A. Staphylococcus aureus
• B. Streptococcus pneumoniae
• C. Mycoplasma
• D. Pneumocystis jirovecii

Answer 1

The Correct Option is B

The presented case involves a patient with AIDS exhibiting a productive cough, fever, and right lower lobe consolidation with a low CD4 count of 55 per microliter. In individuals with AIDS, particularly those with a CD4 count below 200 cells/µL, the immune system is significantly compromised, making them susceptible to various infections. The details provided in this case point towards bacterial pneumonia as a likely cause of the symptoms noted.

Reasoning:

• When assessing the common causes of pneumonia in patients with advanced HIV (CD4 count below 200 cells/µL), Streptococcus pneumoniae is a frequent pathogen due to the immunocompromised state that impairs the body's ability to fight off infections effectively.
• Streptococcus pneumoniae is known for causing typical pneumonia, which matches the described symptoms of productive cough and lobar consolidation seen in this patient.

Conclusion: While other pathogens such as Pneumocystis jirovecii can also cause pneumonia, they typically present with a non-productive cough and interstitial, rather than lobar, infiltrates. The classic bacterial presentation in this case aligns with Streptococcus pneumoniae.

Therefore, the most common cause of the symptoms and findings in this HIV-positive patient is Streptococcus pneumoniae.