What are the likely causes of shortness of breath, fever, and cough in a 72-year-old patient with a 3-month history of dyspnea, 20-day history of fever, and 1-week history of cough?

Likely Causes of Shortness of Breath, Fever, and Cough in a 72-Year-Old Woman

In a 72-year-old woman presenting with 3 months of dyspnea, 20 days of fever, and 1 week of cough, the most likely diagnoses are community-acquired pneumonia, acute exacerbation of underlying chronic bronchitis/COPD, pulmonary embolism, or heart failure, with the prolonged dyspnea preceding acute symptoms suggesting an underlying chronic condition now complicated by acute infection.

Primary Diagnostic Considerations

Community-Acquired Pneumonia

• Fever (38°C or greater), dyspnea, and new cough strongly suggest pneumonia 1
• The 20-day fever duration with recent cough onset (1 week) fits the pattern of progressive lower respiratory tract infection 1
• Key clinical features to assess: tachypnea, tachycardia (>100 bpm), new localizing chest examination signs (crackles, diminished breath sounds), and pleural pain 1
• If CRP is available and >30 mg/L in addition to fever and dyspnea, pneumonia likelihood increases significantly 1
• The absence of runny nose combined with breathlessness and fever makes pneumonia more likely than simple bronchitis 1

Acute Exacerbation of Chronic Bronchitis/COPD

• The 3-month history of dyspnea suggests underlying chronic airways disease that may now be acutely exacerbating 1
• Acute exacerbation presents with sudden deterioration including increased cough, sputum production (potentially purulent), and worsening dyspnea, often preceded by upper respiratory symptoms 1
• Viral infections (rhinovirus, coronavirus, influenza, parainfluenza) trigger approximately one-third of exacerbations, with bacterial superinfection (Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis) commonly following 1
• The 20-day fever is unusually prolonged for simple viral bronchitis, raising concern for bacterial pneumonia or alternative diagnosis 1
• Critical pitfall: Lung function testing should be performed after acute illness resolves if wheezing, prolonged expiration, or smoking history present, as up to 45% of patients with acute cough may have undiagnosed asthma/COPD 1

Pulmonary Embolism (Life-Threatening)

• PE must be excluded in elderly patients with dyspnea, particularly with prolonged symptom duration 1, 2
• The ACCP guidelines emphasize that PE can masquerade as chronic bronchitis exacerbation 2
• High-risk features include: immobilization in past 4 weeks, history of DVT/PE, malignancy, tachycardia, and hemoptysis 1, 2
• Dyspnea and tachycardia without fever or significant sputum production should raise PE suspicion 2
• The 3-month dyspnea history could represent recurrent small emboli 1

Heart Failure

• Heart failure commonly mimics acute exacerbation of chronic bronchitis and must be excluded 1
• Progressive dyspnea over 3 months with acute worsening fits decompensated heart failure pattern 1
• Age 72 years places patient at higher risk for cardiac disease 2
• Look for orthopnea, paroxysmal nocturnal dyspnea, peripheral edema, and elevated jugular venous pressure 1

Secondary Considerations

Tuberculosis (If Endemic Area)

• In endemic regions, TB remains an important cause of chronic cough with fever 1
• The combination of 3-month dyspnea, prolonged fever (20 days), and new cough warrants TB evaluation 1
• Assess for night sweats, weight loss, and hemoptysis 1

Aspiration Pneumonia

• Should be considered in elderly patients, especially with swallowing difficulties, cerebrovascular disease, or psychiatric conditions 1
• The prolonged fever suggests possible complicated aspiration with abscess formation 1

Post-Infectious Complications

• The initial 3-month dyspnea may represent post-viral syndrome with subsequent bacterial superinfection 1
• Long COVID can present with persistent dyspnea and cough, with respiratory symptoms lasting at least 7 months in 40% of patients 1

Critical Diagnostic Algorithm

Immediate Assessment Required:

1. Vital signs: Temperature ≥38°C, respiratory rate >24, heart rate >100, oxygen saturation <98% 1, 2
2. Chest examination: Crackles, diminished breath sounds, pleural rub, wheezing 1
3. Cardiac examination: Elevated JVP, peripheral edema, S3 gallop 1

Essential Investigations:

1. Chest radiograph to identify pneumonia, heart failure, or alternative pathology 1
2. ECG to assess for cardiac ischemia or right heart strain from PE 2
3. CRP measurement: <10 mg/L makes pneumonia less likely; >30 mg/L increases pneumonia probability 1
4. Complete blood count: Leukocytosis suggests bacterial infection 3

Risk Stratification for PE:

• If no fever, minimal sputum, and dyspnea disproportionate to examination findings, obtain D-dimer and consider CTPA 1, 2
• Wells score or similar clinical decision rule should guide PE workup 1

Key Clinical Pitfalls to Avoid

• Do not assume simple bronchitis with 20 days of fever—this duration mandates investigation for pneumonia, TB, or other serious pathology 1
• The 3-month dyspnea history suggests underlying chronic disease; do not attribute all symptoms to acute infection alone 1
• Always exclude PE and heart failure before diagnosing acute exacerbation of chronic bronchitis 1, 2
• In patients with minimal sputum and prolonged fever, consider non-infectious causes including malignancy 1
• If patient has risk factors for aspiration, maintain high suspicion for complicated aspiration pneumonia or abscess 1