For a patient with recent pulmonary embolism and pneumonia on anticoagulation who continues to have nausea, vomiting, fever, chills, and dyspnea despite an improving chest CT, what additional evaluations should be performed during his hospital stay?

Evaluate for Inadequately Treated Infection and Alternative Fever Sources

Despite radiographic improvement, your patient's persistent fever, chills, nausea, vomiting, and dyspnea warrant immediate investigation for inadequately treated pneumonia, intra-abdominal pathology (particularly if recent surgery), and consideration that PE itself may be causing fever. 1

Immediate Diagnostic Workup

Chest Evaluation

• Perform thoracic bedside ultrasound to identify pleural effusions or parenchymal pathology that may not be apparent on CT, especially since expertise should be available in the hospital setting 1
• Consider that PE can directly induce pneumonia-like lung injury beyond simple infarction—this may explain persistent symptoms despite anticoagulation 2, 3
• Fever can be a primary manifestation of PE itself, sometimes resolving only after adequate anticoagulation 2

Abdominal Assessment

Critical caveat: If this patient had recent thoracic, abdominal, or pelvic surgery:

• Perform CT of abdomen/pelvis immediately in collaboration with surgical service if initial workup doesn't identify a source 1
• Even without recent surgery, if he has any abdominal symptoms, abnormal liver enzymes, or concerning physical exam findings, obtain formal abdominal ultrasound 1
• Do NOT routinely order abdominal imaging if he has no abdominal signs, symptoms, or liver function abnormalities 1

Infection Reassessment

• Verify antibiotic adequacy: Ensure pneumonia coverage is appropriate for severity and potential resistant organisms
• Blood cultures: If not already obtained or if new fever spikes
• Check for empyema: The thoracic ultrasound mentioned above specifically addresses this
• Consider that pneumonia and PE frequently coexist—one study found 12.5% of suspected pneumonia patients actually had PE, and the combination is associated with persistent symptoms 4, 5

Advanced Imaging if Initial Workup Unrevealing

If the above evaluations fail to establish an etiology:

• Consider FDG-PET/CT if transport risk is acceptable 1
• This is particularly useful for occult infection sources in persistently febrile patients

Key Clinical Pitfalls

Do not assume radiographic improvement equals clinical resolution. The disconnect between improving CT and worsening symptoms should raise concern for:

1. Inadequate antibiotic therapy for pneumonia (wrong spectrum, resistant organism, inadequate penetration)
2. Complicated pneumonia (empyema, lung abscess) requiring drainage
3. PE-induced inflammatory response that may take time to resolve despite anticoagulation 2, 3
4. Concurrent but unrelated infection source (intra-abdominal, catheter-related if central line present)

Regarding central venous catheters: If present, obtain simultaneous central and peripheral blood cultures 1

Temperature Management

• Avoid routine antipyretics solely for temperature reduction in critically ill patients 1
• Use antipyretics only if the patient specifically desires comfort from fever reduction 1

Point-of-Care Ultrasound Utility

Given diagnostic uncertainty with persistent symptoms despite improving imaging, POCUS is appropriate as an adjunct to standard evaluation 6. This aligns with using thoracic ultrasound for pleural/parenchymal assessment and abdominal ultrasound if indicated by clinical findings.

The combination of PE and pneumonia creates diagnostic complexity—both conditions share overlapping symptoms, and PE can actually induce pneumonia-like lung injury independent of infection 3. Your patient's persistent systemic symptoms despite radiographic improvement mandate aggressive investigation for undertreated infection or complications rather than assuming the clinical course will parallel imaging findings.