5 Discussion:
Pneumocystis, a group of microorganisms causing pneumonia, has
traditionally been classified as a fungus due to its similarities to
other fungi [6]. However, it is important to note that recent
research has revealed that its classification is still a topic of debate
in the scientific community [6]. Furthermore, the inability to
cultivate Pneumocystis in laboratory conditions poses an additional
barrier to studying and understanding this microorganism [6].
Patients with pneumocystis pneumonia (PCP) commonly present with a
variety of symptoms, including low-grade fever, productive cough, and
shortness of breath. In fact, studies have shown that approximately
80-100% of PCP patients experience low-grade fever, while 95% present
with both productive cough and shortness of breath. These symptoms are
often nonspecific and can mimic other respiratory conditions, making the
diagnosis of PCP challenging [7, 8, 9]. Our patient initially
presented with symptoms such as low-grade fever, weight loss, and a
productive cough, which persisted despite previous antibiotic treatment.
The diagnosis of PCP poses significant challenges due to the
non-specific clinical manifestations that can mimic various infectious
disease such as tuberculosis [10, 11]; Nocardia; fungal infections
and COVID-19 [12 - 21] as well as non-infectious diseases.
Additionally, imaging techniques such as chest X-rays and CT scans are
not always definitive in diagnosing PCP. In fact, 25% of initial PCP
cases may show normal chest X-ray results, and CT scans may not clearly
indicate the type of abnormality. While bilateral interstitial
infiltrates are commonly observed in PCP, the radiological findings can
also be atypical [22]. In the presented case, the chest X-ray
revealed diffuse interstitial prominence with nodular infiltrates which
is also can be associated with tuberculosis, fungal infections,
Nocardia, sarcoidosis and Metastatic carcinoma with lymphangitis
carcinomatosis.
Further investigations, including a CT scan and bronchoscopy, were
conducted. The CT scan revealed ground glass opacities with intralobular
septal thickening and nodular infiltrates. Bronchial washings were
collected for microbiology, culture, and cytology testing. Acid-fast
bacilli smear and culture, Nocardia and fungal smears and cultures, and
GeneXpert testing for tuberculosis were negative. Additionally, cytology
ruled out malignancy but showed a three-dimensional alveolar cast with a
honeycomb appearance. Based on the clinical presentation, CT findings,
and the presence of honeycomb-like alveolar casts, a presumptive
diagnosis of PCP was made. The diagnosis was supported by the patient’s
positive HIV status. PCP is an opportunistic infection commonly seen in
individuals with weakened immune systems, such as those with HIV/AIDS.
Additionally, Trimethoprim-sulfamethoxazole (TMP-SMX) is considered the
first-line treatment for mild-to-severe cases of PCP [13]. The
recommended dosage for TMP-SMX is typically 15mg/kg/day. However,
intravenous pentamidine is also an effective alternative to TMP-SMX. It
should be noted that pentamidine carries a higher risk of adverse events
compared to TMP-SMX. For individuals with mild or moderate PCP, the oral
alternative regimen is atovaquone. Although atovaquone is less effective
than TMP-SMX, it is generally better tolerated [22, 34]. In cases of
moderate to severe PCP, which is defined as having an arterial oxygen
pressure less than 70 torr on room air and an alveolar-arterial oxygen
gradient greater than 35 torr, adjunctive corticosteroid therapy is
recommended [23]. In our case, the treatment was initiated with
Septran (sulfamethoxazole and trimethoprim) for a total of 21 days,
resulting in significant clinical improvement. Follow-up chest X-rays
showed resolution of the previously observed abnormalities, and the
patient fully recovered.
In conclusion, this case emphasizes the significance of including
opportunistic infections, like PCP, in the differential diagnosis of
respiratory symptoms in individuals with HIV/AIDS. It is crucial to
promptly diagnose and initiate appropriate treatment for improved
patient outcomes. Collaboration between pulmonologists, infectious
disease specialists, and HIV specialists can greatly assist in
accurately diagnosing and managing such cases. The patient’s positive
HIV status, along with the clinical presentation, CT findings, and the
presence of honeycomb-like alveolar casts, supported the diagnosis of
PCP.