What is the appropriate diagnosis and treatment for pneumonia symptoms?

Pneumonia: Clinical Presentation and Diagnostic Approach

Clinical Symptoms and Signs

Pneumonia typically presents with respiratory symptoms including new or increased cough, sputum production, and dyspnea, often accompanied by fever, though elderly patients may present atypically with confusion or worsening of chronic conditions rather than classic respiratory symptoms. 1

Respiratory Manifestations

• Cough with variable sputum production (purulent sputum suggests bacterial etiology) 2, 1
• Dyspnea and shortness of breath, which may progress rapidly 2
• Pleuritic chest pain indicating pleural involvement 3
• Tachypnea is particularly important as it correlates with disease severity 1

Systemic Manifestations

• Fever (temperature >38°C) is common, though hypothermia (≤36°C) may occur in severe cases 4
• Confusion or altered mental status, especially in elderly patients who may lack typical respiratory symptoms 1
• Tachycardia and signs of systemic illness 3
• Chills and general malaise 2

Physical Examination Findings

• Auscultatory signs of consolidation including crackles, bronchial breath sounds, or decreased breath sounds 3
• Hypoxemia detected by pulse oximetry or arterial blood gas 1
• Signs of respiratory distress including use of accessory muscles 2

Diagnostic Confirmation

Radiographic Findings

Standard posteroanterior and lateral chest radiographs are essential for confirming the diagnosis of pneumonia, as clinical symptoms alone are not specific enough. 1, 3

Early Stage Imaging (1-3 days after symptom onset)

• Single or multiple scattered patchy or agglomerated ground-glass opacities 2
• Honeycomb-like or grid-like thickened interlobular septa 2

Progression Stage Imaging (3-7 days)

• Fused large-scale consolidation with air-bronchogram inside 2
• Multilobar involvement is associated with increased severity and poorer prognosis 1

Consolidation Stage (7-14 days)

• Multiple patchy consolidations of lighter density and smaller range 2

Dissipation Stage (2-3 weeks)

• Patchy consolidation or strip-like opacity with gradual resolution 2
• Grid-like thickening of interlobular septum and bronchial wall thickening 2

Important Radiographic Considerations

• Pleural effusions may be present and require evaluation, particularly if not responding to therapy 1
• Radiographic clearing typically lags behind clinical improvement, with only 60% of healthy patients under 50 showing complete resolution at 4 weeks, and only 25% of older patients or those with comorbidities 1

Laboratory Findings

Hematologic Changes

• Leukocyte count may be decreased, normal, or elevated (>10,000/μL or <4,000/μL suggests pneumonia) 2, 4
• Decreased lymphocyte count or increased monocytes in early disease 2
• Absolute lymphocyte value <0.8 × 10⁹/L warrants high attention and recheck after 3 days 2
• Decreased CD4 and CD8 T cells may be significantly reduced 2

Additional Laboratory Tests

• Increased C-reactive protein (CRP) indicating inflammatory response 2
• Increased procalcitonin (PCT) suggesting bacterial infection 2
• Elevated liver enzymes, muscle enzymes, and myoglobin in some patients 2
• Increased erythrocyte sedimentation rate (ESR) 2

Differential Diagnosis

Pneumonia must be distinguished from other viral pneumonias (influenza, parainfluenza, adenovirus, respiratory syncytial virus, rhinovirus), atypical bacterial infections (mycoplasma, chlamydia), and non-infectious diseases. 2

Infectious Mimics

• Other viral pneumonias: influenza viruses, parainfluenza virus, adenovirus, respiratory syncytial virus, rhinovirus, human metapneumovirus, SARS-CoV 2
• Atypical bacterial infections: mycoplasma pneumonia, chlamydia pneumonia 2
• Tuberculosis in appropriate clinical context 2

Non-Infectious Mimics

• Vasculitis 2
• Dermatomyositis 2
• Organizing pneumonia 2
• Pulmonary embolism 5
• Malignancy 5

Pathogen Detection

Respiratory Sampling

• Flu antigen testing (A, B, H7N-subtypes) via throat swabs for rapid screening, though false negative rate is relatively high 2
• Respiratory virus nucleic acid detection for common viruses, mycoplasma, and chlamydia 2
• 2019-nCoV nucleic acid detection (when applicable) via fluorescence quantitative PCR from throat swab or respiratory samples, preferably from multiple samples 2
• Sputum Gram stain and culture if drug-resistant bacteria or unusual organisms suspected 1

Blood Testing

• Blood cultures may be valuable, particularly in severe cases 1

Age-Specific Considerations

Pediatric Pneumonia

• Incidence is highest in children under 5 years (36.0/1000/year) compared to 5-14 years (16.2/1000/year) 2
• Strong male predominance in those under 5 years 2
• Streptococcus pneumoniae has highest incidence (8.6/1000/year) in children under 5 2

Adult Pneumonia

• Older adults (≥65 years) are at highest risk for CAP and complications including sepsis, acute respiratory distress syndrome, and death 4
• Only 38% of hospitalized patients have a pathogen identified 4
• Up to 40% have viruses identified as likely cause when pathogen is found 4
• Streptococcus pneumoniae identified in approximately 15% of patients with identified etiology 4

Common Pitfalls

• Dehydration can mask pneumonia radiographically and impacts mortality, with moderate-quality evidence showing dehydration doubles odds of medium-term mortality 1
• Clinical symptoms alone are insufficient for diagnosis as they are not unique to pneumonia 3
• Atypical presentations in elderly may lack fever or respiratory symptoms, presenting only with confusion 1
• Radiographic resolution lags clinical improvement significantly, so do not expect rapid clearing on repeat imaging 1