Recap and Resources on Case conference 7/29/2024

On Monday’s case conference, Shuang presented a very educational case of uncommon presentations of a common diagnosis, taking us through the journey of suspected pulmonary infection in an immunocompromised patient, while touching on several important schemas and topics.

Diagnostic journey recap:

— We started with a 31-year-old patient with fever, cough and pleuritic chest pain. We promptly considered pneumonia through pattern recognition/type I thinking, while being cognizant of broader Ddx that combines inflammation (“I-MADE”) and pleuritic chest pain.

— We then discussed about her antibiotic failure of outpatient CAP regimen. Her history of lupus stretched our Ddx for autoimmune causes of chest inflammation, and her immunocompromised state (being on meds against both T and B cells) prioritized and broadened our infectious Ddx to go beyond base rate of viral/bacterial/atypicals, to also include TB/NTM/nocardia and fungal.

— Labs were less concerning for lupus flare, and we interpreted normal WBC and negative procalcitonin with caution. Chest imaging findings consolidation/GGOs supported pneumonia (pus), though could also represent water/blood/protein/cells.

— With the lack of response to empiric inpatient CAP regimen and extended-spectrum antibiotics, infectious workup for pneumonia in an immunocompromised host was pursued, and we discussed caveats on interpreting some of the tests. Eventually, BAL was indicated, which revealed Covid-19 (despite negative results on swabs).

— Patient improved once she was started on remdesivir and Paxlovid, supporting Covid-19 as a culprit rather than a bystander. The case thus highlighted unique features of Covid-19 in immunocompromised patients.

Teaching point recap: please review the following schemas/topics

— Build a strong illness script for community-acquired pneumonia (CAP): UpToDate overview and IDSA guideline are good resources, also check  Shuang’s PPT slides

— Review Ddx framework for Inflammation thought train (“I-MADE”, a more expanded version here), pleuritic chest pain, and antibiotic failure

— Reflect on the Approach to suspected pulmonary infection in an immunocompromised patient, build a note for yourself to review/refine in the future (eg, the degree/type of immunodeficiency may alter the Ddx). Our very own residents Mark (who just graduated) and Gwen have reviewed this topic at prior case conferences: see Mark’s excellent summary and Gwen’s interesting case video linked on these pages

— More advanced topics include the interpretation of tests such as fungal markers