In a patient with asthma who was treated for pneumonia two weeks ago and now has persistent shortness of breath with a normal chest radiograph, what is the most likely cause and recommended management?

Post-Pneumonia Persistent Dyspnea in Asthmatic Patient

The most likely cause is an asthma exacerbation triggered by the recent pneumonia, and you should immediately assess peak expiratory flow, administer high-dose inhaled beta-agonists, and initiate or increase systemic corticosteroids. 1

Immediate Assessment Required

Your first priority is determining disease severity through objective measures:

• Measure peak expiratory flow (PEF) immediately and compare to the patient's predicted or personal best value—a PEF <50% indicates severe disease requiring aggressive treatment 1
• Assess ability to speak in complete sentences; inability to do so signals severe exacerbation 1
• Check vital signs: respiratory rate >25/min, heart rate >110 bpm, or oxygen saturation <92% indicate severe disease 1

Most Likely Diagnosis: Post-Infectious Asthma Exacerbation

The clear chest x-ray effectively rules out persistent or recurrent pneumonia, making asthma exacerbation the primary concern 2. Respiratory infections commonly trigger prolonged bronchial hyperreactivity in asthmatics, causing symptoms that persist weeks after radiographic resolution 1.

Key clinical reasoning: The incidence of pneumonia in uncomplicated asthma exacerbation is exceedingly low (<2%), and your patient already has a clear radiograph 2. The persistent dyspnea two weeks post-pneumonia in an asthmatic strongly suggests reactive airway disease rather than ongoing infection 2.

Immediate Treatment Protocol

First-Line Bronchodilator Therapy

• Administer salbutamol 5 mg or terbutaline 10 mg via nebulizer with oxygen immediately 1
• Alternative if nebulizer unavailable: 2 puffs via large volume spacer, repeated 10-20 times 1
• Reassess in 15-30 minutes to determine response 1

Systemic Corticosteroids

• Give prednisolone 30-60 mg orally immediately without delay—clinical benefits require 6-12 hours to manifest 1
• Continue prednisolone 30-60 mg daily for 1-3 weeks (not a short course) to reduce relapse rates 1
• Step up or continue inhaled corticosteroid therapy for long-term control 1

Critical Pitfalls to Avoid

Do not prescribe antibiotics unless there is clear evidence of bacterial infection—the clear chest x-ray argues strongly against ongoing pneumonia 2, 3. Routine antibiotic use for post-infectious bronchial symptoms is not justified and contributes to resistance 2.

Do not assume the clear x-ray means no pathology exists. Chest radiographs have limited sensitivity for detecting early or mild pneumonia, but in this clinical context with symptoms two weeks post-treatment, asthma exacerbation is far more likely than occult infection 2.

When to Consider Advanced Imaging

CT chest is warranted only if:

• The patient fails to improve after appropriate asthma treatment 2
• You suspect complications like pulmonary embolism (given immobility from recent illness) 2
• The patient has high-risk features: advanced age, significant comorbidities, or unreliable follow-up 2

CT is more sensitive than chest x-ray for pneumonia (detecting 27-33% of cases missed on radiograph), but given the clinical context and clear x-ray, empiric asthma treatment is more appropriate than immediate CT 2.

Hospital Admission Criteria

Admit immediately if:

• PEF <33% predicted after initial treatment 1
• Oxygen saturation <92% on room air 1
• Silent chest, cyanosis, or confusion (life-threatening features) 1
• Inability to complete sentences in one breath persists after treatment 1

Follow-Up Plan

• Schedule primary care follow-up within 1 week and respiratory specialist within 4 weeks 1
• Provide peak flow meter and written asthma action plan for self-monitoring 1
• Recheck if symptoms worsen or fail to improve within 48-72 hours of treatment initiation 2

Alternative Diagnoses to Consider (If Asthma Treatment Fails)

If the patient does not respond to appropriate asthma therapy:

• Pulmonary embolism: Recent immobility from pneumonia increases risk; consider D-dimer and CT pulmonary angiography 2
• Cardiac asthma/heart failure: Though less likely with clear x-ray, consider if risk factors present 3
• Post-infectious bronchitis: May cause prolonged cough but should improve with bronchodilators 2