What is the best approach to manage a patient with asthma versus pneumonia, considering factors such as disease severity, patient age, and immune status?

Distinguishing and Managing Asthma Exacerbation vs. Pneumonia

The critical first step is determining whether the patient has an acute asthma exacerbation, pneumonia, or both conditions simultaneously, as this fundamentally changes management—asthma requires bronchodilators and systemic corticosteroids while pneumonia requires antibiotics, and missing concurrent bacterial infection in an asthmatic can be fatal. 1

Immediate Clinical Assessment

Measure objective parameters immediately to distinguish between these conditions and assess severity 1:

• Respiratory rate (>25 breaths/min suggests severe asthma or pneumonia) 2
• Heart rate (>110 bpm indicates moderate-severe disease) 2
• Peak expiratory flow (PEF) if asthma suspected (<50% predicted = severe asthma) 2
• Oxygen saturation (hypoxia suggests pneumonia or life-threatening asthma) 2, 3
• Temperature (fever strongly suggests bacterial pneumonia) 1
• Ability to speak in complete sentences (inability = severe asthma) 2

Key Distinguishing Features

Findings Favoring Pneumonia Over Asthma Alone:

• Fever with coarse breath sounds strongly suggests bacterial infection requiring antibiotics 1
• Productive cough with purulent sputum (asthma typically has non-productive cough) 1
• Focal consolidation on chest radiograph (asthma shows hyperinflation without infiltrates) 3
• Elevated C-reactive protein and white blood cell count 3
• Unilateral findings on examination (asthma is bilateral) 3

Findings Favoring Asthma Exacerbation:

• Diffuse wheezing throughout both lung fields 2
• Known history of asthma with typical triggers (viral infection, allergens) 1
• PEF <50% of predicted or personal best 2
• Response to bronchodilator therapy within 15-30 minutes 2

Critical Recognition: Both Can Coexist

Respiratory infections are the most common trigger for acute asthma exacerbations, accounting for approximately 50% of episodes 1. Patients with underlying asthma are at 2.4 times increased risk for invasive pneumococcal disease compared to those without asthma 2. Therefore, assume concurrent bacterial pneumonia in any asthmatic with fever and productive cough until proven otherwise 1.

Management Algorithm

If Asthma Exacerbation Without Pneumonia (PEF >50%, no fever, no infiltrate):

Immediate treatment 2:

• Nebulized salbutamol 5 mg or terbutaline 10 mg with oxygen if available 2
• Prednisolone 30-60 mg orally (benefits take 6-12 hours, so give immediately) 2, 1
• Reassess PEF at 15-30 minutes 2

If PEF improves to >50-75% predicted 2:

• Continue bronchodilators every 4 hours 2
• Complete 5-7 days of oral prednisolone 2
• Follow-up within 48 hours 2

If Severe Asthma (PEF <50%, unable to complete sentences):

Immediate treatment 2:

• Oxygen 40-60% to maintain SaO2 >92% 2
• Nebulized salbutamol 5 mg or terbutaline 10 mg via oxygen-driven nebulizer 2
• Add ipratropium 0.5 mg to nebulizer 2
• Prednisolone 30-60 mg orally OR IV hydrocortisone 200 mg 2
• Arrange hospital admission if features persist after initial treatment 2

If Life-Threatening Asthma (PEF <33%, silent chest, confusion, exhaustion):

Immediate ICU-level care 2:

• All of the above treatments 2
• IV aminophylline 250 mg over 20 minutes (if not on oral theophyllines) 2
• Chest radiograph to exclude pneumothorax 2
• Arterial blood gas (normal or high PaCO2 in breathless asthmatic = life-threatening) 2
• Immediate ICU admission 2

If Pneumonia Suspected (fever, productive cough, infiltrate on imaging):

For outpatient management (healthy adults without comorbidities) 4:

• Amoxicillin 1 g orally three times daily for 5-7 days as first-line 4
• Doxycycline 100 mg twice daily as alternative 4
• Avoid macrolide monotherapy if local pneumococcal resistance >25% 4

For outpatient management (adults with comorbidities including asthma) 4:

• Amoxicillin-clavulanate 875/125 mg twice daily PLUS azithromycin 500 mg day 1, then 250 mg daily for days 2-5 4
• Alternative: Respiratory fluoroquinolone (levofloxacin 750 mg daily or moxifloxacin 400 mg daily) 4

For hospitalized patients (non-ICU) 4, 3:

• Ceftriaxone 1-2 g IV daily PLUS azithromycin 500 mg daily 4, 3
• Alternative: Respiratory fluoroquinolone monotherapy (levofloxacin 750 mg IV daily or moxifloxacin 400 mg IV daily) 4
• Administer first antibiotic dose in emergency department—delayed administration beyond 8 hours increases 30-day mortality by 20-30% 4, 3

For severe pneumonia (ICU admission required) 4, 3:

• Ceftriaxone 2 g IV daily PLUS azithromycin 500 mg IV daily 4, 3
• Alternative: Ceftriaxone 2 g IV daily PLUS levofloxacin 750 mg IV daily 4

If Both Asthma and Pneumonia Present Simultaneously:

Treat both conditions aggressively 1:

• Bronchodilators (nebulized salbutamol ± ipratropium) 2
• Systemic corticosteroids (prednisolone 30-60 mg or IV hydrocortisone 200 mg) 2
• Antibiotics as per pneumonia guidelines above 4, 1
• Oxygen to maintain SaO2 >92% 2, 3
• Hospital admission for close monitoring 2, 3

Critical Pitfalls to Avoid

• Never delay systemic corticosteroids in acute severe asthma—benefits take 6-12 hours to manifest, so early administration is crucial 2, 1
• Never underestimate severity—patients with severe asthma may not appear distressed initially 2, 1
• Never use sedation in acute asthma—this is absolutely contraindicated 2
• Never delay antibiotics beyond 8 hours in hospitalized pneumonia patients—this increases mortality by 20-30% 4, 3
• Never use macrolide monotherapy for hospitalized pneumonia patients—inadequate coverage for typical bacterial pathogens 4
• Never assume asthma alone in a febrile patient with productive cough—concurrent bacterial pneumonia is common and requires antibiotics 1
• Never give antibiotics for uncomplicated asthma exacerbations—antibiotics only indicated if bacterial infection present 2

Duration and Follow-Up

For asthma exacerbations 2:

• Continue prednisolone 30-60 mg daily for 5-7 days 2
• Follow-up within 24-48 hours for severe cases, within 48 hours for moderate cases 2
• Modify long-term asthma treatment at review 2

For pneumonia 4, 3:

• Treat for minimum 5 days and until afebrile for 48-72 hours 4, 3
• Typical duration 5-7 days for uncomplicated cases 4, 3
• Switch to oral antibiotics when hemodynamically stable, clinically improving, and able to take oral medications 4, 3
• Clinical review at 6 weeks for all hospitalized patients 3

Special Considerations by Age and Immune Status

Elderly patients (≥65 years) 5, 6, 7:

• Lower threshold for hospitalization using CURB-65 score 3, 6
• Higher risk of atypical presentation of pneumonia 5, 7
• Consider amoxicillin-clavulanate over amoxicillin alone due to higher rates of β-lactamase-producing organisms 6
• Dose adjustments for renal impairment common in this age group 6

Immunocompromised patients 2:

• Higher risk for invasive pneumococcal disease 2
• Consider broader spectrum antibiotics earlier 4
• Lower threshold for hospital admission 3
• Ensure pneumococcal vaccination status up to date 2, 3

Patients with asthma on inhaled corticosteroids 8:

• Fluticasone propionate associated with 7.92 times increased risk of pneumonia hospitalization compared to non-users 8
• Budesonide shows no significant association with pneumonia risk 8
• Maintain high index of suspicion for pneumonia in asthmatics on high-dose ICS 8