Is this likely pneumonia (PNA) given the chest radiograph findings?

Is This Likely Pneumonia?

Yes, this chest radiograph is highly suggestive of pneumonia, particularly given the new patchy opacity on the right side, with the left-sided opacity being stable from prior imaging. The radiographic findings of bilateral patchy opacities, especially with new right-sided changes, meet diagnostic criteria for pneumonia when correlated with clinical presentation 1, 2.

Radiographic Interpretation

The chest X-ray demonstrates key findings consistent with pneumonia:

• Bilateral patchy opacities are present, which is a characteristic radiographic pattern of pneumonia 1, 3
• New right-sided opacity is particularly significant, as new or progressive infiltrates strongly suggest active infection 1, 2
• Stable left-sided opacity may represent either resolving pneumonia, chronic changes, or a separate process requiring clinical correlation 1
• Cardiomegaly is noted, which may be a comorbid condition but doesn't exclude pneumonia 1

Diagnostic Criteria for Pneumonia

According to IDSA/ATS guidelines, pneumonia diagnosis requires both clinical features AND radiographic infiltrate 2, 4. The chest radiograph is the standard imaging modality for initial evaluation and demonstrates the necessary infiltrate in this case 1.

Clinical Correlation Required

While the radiograph is suggestive, you must assess for:

• Vital sign abnormalities: Temperature ≥38°C or ≤36°C, heart rate >100 bpm, respiratory rate >24 breaths/min 2, 5
• Respiratory symptoms: New or increased cough, dyspnea, pleuritic chest pain 2, 4
• Physical examination findings: New focal crackles, diminished breath sounds, bronchial breath sounds 2, 5
• Systemic symptoms: Fever, sweats, chills, myalgias 2

Important caveat: In elderly patients or those with inadequate immune response, pneumonia may present with non-respiratory symptoms such as confusion, failure to thrive, or falls, and fever may be absent despite tachypnea being present 1.

Differential Considerations

The bilateral patchy pattern requires consideration of alternative diagnoses:

• Pulmonary edema (given the cardiomegaly, though typically more symmetric and associated with pleural effusions, which are absent here) 1
• Atypical pneumonia (viral or Mycoplasma, which can produce interstitial/patchy patterns) 3
• Aspiration pneumonia (if risk factors present) 1
• Underlying malignancy (particularly important given stable left-sided opacity - follow-up imaging in 6-12 weeks is recommended to ensure resolution and exclude malignancy) 1

Next Steps

If Clinical Suspicion Remains High Despite Equivocal Findings:

• CT chest without IV contrast is the next appropriate imaging modality if the chest radiograph were negative or equivocal and clinical suspicion remained high 1
• However, in this case, the radiograph is positive, not equivocal, so CT is not immediately necessary unless complications are suspected 1

Testing Recommendations:

• Test for COVID-19 and influenza when these viruses are circulating in the community, as this affects treatment decisions 4
• Consider inflammatory markers (CRP >100 mg/L supports pneumonia; CRP <20 mg/L makes it unlikely) if diagnosis remains uncertain 2

Treatment Considerations:

If bacterial pneumonia is suspected without risk factors for resistant organisms, β-lactam/macrolide combination therapy (e.g., ceftriaxone plus azithromycin) for minimum 3 days is appropriate for hospitalized patients 4.

Critical Follow-Up

A follow-up chest radiograph in 6-12 weeks is recommended to confirm resolution of the opacities and exclude underlying malignancy, particularly given the stable left-sided opacity and the patient's apparent cardiomegaly 1. This is especially important in patients who are older, smokers, or have COPD 1.