Thank you to Dr. Palevsky and Dr. Gluckman for helping us discuss a really interesting case of an 82 year old gentleman with persistent hypoxia who was ultimately found to have a new diagnosis of HIV presenting with PJP pneumonia.
We discussed techniques for performing a thorough pulmonary exam: (images: https://meded.ucsd.edu/clinicalmed/lung.htm)
Many of these exam maneuvers use principles of physics to help us determine if the lung tissue is aerated normally, or if there is a process compromising aeration and anatomy. Since sound waves are vibrations, they are transmitted differently through air and solid/liquid media. Thus processes causing consolidation of lung tissue, alveolar filling, or other anatomic/functional pathology will transmit sound waves differently – leading to different findings on egophony, whispered pectoriloquy, tactile fremitus, and percussion.
Our patient experienced respiratory distress and decompensation following an upper endoscopy procedure. We discussed that his clinical circumstances were concerning for aspiration – which can cause either a pneumonitis (transient inflammation without leading to infection) or a pneumonia (infection). Dr. Palevsky taught us that due to anatomy of the airways branching, aspiration does not always go to the lung bases, and it is important to listen in the central lung fields too.
After a course of treatment for aspiration pneumonia, our patient continued to be hypoxic and tachypneic, so additional workup was pursued and ultimately he was diagnosed with HIV/AIDS and PJP pneumonia. We learned from Dr. Gluckman that 6% of new HIV diagnoses are made in patients older than 80 years, so always think about sending an HIV test on all of your patients, regardless of their age!
PJP is currently classified as a fungus, which is normally cleared by host macrophages and CD4 cells coordinating an immune response – which is why patients with CD 4 < 200 (and other immunocompromised states) are at risk of this infection. Typical symptoms include progressive shortness of breath especially with exertion, fever, and tachypnea, although patients can be asymptomatic. Classic imaging shows bilateral diffuse patchy pulmonary infiltrates. A very elevated beta-D-glucan is supportive of this diagnosis, but the definitive diagnosis requires confirming the presence of PJP in the respiratory secretions or sputum. PJP does not grow in cultures, and obtaining samples can sometimes be difficult and require invasive techniques.
Treatment recommendations depend on severity of disease. Our patient progressed to respiratory failure requiring mechanical ventilation, so he definitely had severe disease! The recommended regimen in that case is high dose trimethoprim-sulfamethoxazole (weight-based) for 21 days, given IV until patient stabilizes. Patients with severe disease should also be treated with steroids. Finally, studies support early initiation of ART in patients presenting with PJP pneumonia.