Cough / suspected respiratory infection
A streamlined, differential-led presentation for rapid clinical review.
Twenty-second review
- Respiratory infection inflames airways or alveoli, increasing secretions, work of breathing, ventilation-perfusion mismatch, and sometimes systemic inflammatory physiology.
- Hypoxia, severe work, confusion, shock, hemoptysis, immune compromise, or rapidly worsening symptoms raises concern for pneumonia or sepsis.
- Keep heart failure or pe in the differential; overlapping or concurrent illness remains possible.
- For cough / suspected respiratory infection, trends and combinations of findings are more informative than one isolated vital sign.
Compare the clinical patterns
The repeated material is grouped inside each possibility. Open only the condition you need.
PneumoniaTime-sensitive high-risk possibility
HPI
Clarify onset and sputum; fever or infectious exposure; work of breathing and spo₂.
Signs & symptoms
Focal crackles, hypoxia, tachypnea, hypotension, or altered mentation.
Focused exam
Observe position, speech, accessory-muscle use, pattern, depth, and chest symmetry; Auscultate all lung fields and reassess after movement or treatment.
Brief pathophysiology
Pneumonia may cause cough / suspected respiratory infection through a time-sensitive process capable of rapid physiological deterioration.
What the trend may show
Respiratory infection may impair oxygenation and trigger systemic illness. Older or immunocompromised patients may lack fever, so trend all four observations and mental status.
Respiratory rate (breaths/min)
Often risesTachypnea can be an early marker of respiratory or systemic illness.
Oxygen saturation (SpO₂)
May fallParenchymal disease can impair gas exchange; compare with baseline.
Temperature (°C)
May rise or fallFever is common, but normal or low temperature does not exclude serious infection.
Heart rate (bpm)
Often risesTachycardia may reflect fever, hypoxia, dehydration, or sepsis.
Front-load in the triage report
- Pneumonia: Focal crackles, hypoxia, tachypnea, hypotension, or altered mentation.
- Onset and sputum?
- Fever or infectious exposure?
SepsisTime-sensitive high-risk possibility
HPI
Clarify fever or infectious exposure; work of breathing and spo₂; lung sounds.
Signs & symptoms
Focal crackles, hypoxia, tachypnea, hypotension, or altered mentation.
Focused exam
Auscultate all lung fields and reassess after movement or treatment; Assess cough and sputum, lung sounds, focality, work of breathing, hydration, fever, chest pain, and infection risk.
Brief pathophysiology
Sepsis may cause cough / suspected respiratory infection through a time-sensitive process capable of rapid physiological deterioration.
What the trend may show
No single vital sign diagnoses sepsis. New tachypnea, abnormal temperature, tachycardia, or falling pressure—especially with altered mentation or poor perfusion—supports organ dysfunction and urgency.
Respiratory rate (breaths/min)
May rise earlyTachypnea is included in NEWS2 and can precede overt hypotension.
Temperature (°C)
High or lowAbsence of fever does not exclude sepsis; hypothermia is concerning.
Heart rate (bpm)
Often risesTachycardia is common but may be blunted by age or medication.
Blood pressure (mmHg)
May fallRelative hypotension and trend matter; profound hypotension can be late.
Front-load in the triage report
- Sepsis: Focal crackles, hypoxia, tachypnea, hypotension, or altered mentation.
- Fever or infectious exposure?
- Work of breathing and SpO₂?
Viral bronchitisCommon presentation pattern
HPI
Clarify onset and sputum; fever or infectious exposure; work of breathing and spo₂.
Signs & symptoms
Cough and systemic symptoms with preserved oxygenation and perfusion may occur.
Focused exam
Observe position, speech, accessory-muscle use, pattern, depth, and chest symmetry; Auscultate all lung fields and reassess after movement or treatment.
Brief pathophysiology
Viral bronchitis may explain the presenting symptoms through a common clinical mechanism, while serial assessment checks for complications or an alternate cause.
What the trend may show
Respiratory infection may impair oxygenation and trigger systemic illness. Older or immunocompromised patients may lack fever, so trend all four observations and mental status.
Respiratory rate (breaths/min)
Often risesTachypnea can be an early marker of respiratory or systemic illness.
Oxygen saturation (SpO₂)
May fallParenchymal disease can impair gas exchange; compare with baseline.
Temperature (°C)
May rise or fallFever is common, but normal or low temperature does not exclude serious infection.
Heart rate (bpm)
Often risesTachycardia may reflect fever, hypoxia, dehydration, or sepsis.
Front-load in the triage report
- Cough and systemic symptoms with preserved oxygenation and perfusion may occur.
- Onset and sputum?
- Fever or infectious exposure?
Uncomplicated infectionCommon presentation pattern
HPI
Clarify fever or infectious exposure; work of breathing and spo₂; lung sounds.
Signs & symptoms
Cough and systemic symptoms with preserved oxygenation and perfusion may occur.
Focused exam
Auscultate all lung fields and reassess after movement or treatment; Assess cough and sputum, lung sounds, focality, work of breathing, hydration, fever, chest pain, and infection risk.
Brief pathophysiology
Uncomplicated infection may explain the presenting symptoms through a common clinical mechanism, while serial assessment checks for complications or an alternate cause.
What the trend may show
Respiratory infection may impair oxygenation and trigger systemic illness. Older or immunocompromised patients may lack fever, so trend all four observations and mental status.
Respiratory rate (breaths/min)
Often risesTachypnea can be an early marker of respiratory or systemic illness.
Oxygen saturation (SpO₂)
May fallParenchymal disease can impair gas exchange; compare with baseline.
Temperature (°C)
May rise or fallFever is common, but normal or low temperature does not exclude serious infection.
Heart rate (bpm)
Often risesTachycardia may reflect fever, hypoxia, dehydration, or sepsis.
Front-load in the triage report
- Cough and systemic symptoms with preserved oxygenation and perfusion may occur.
- Fever or infectious exposure?
- Work of breathing and SpO₂?
Heart failureImportant alternative presentation
HPI
Clarify onset and sputum; fever or infectious exposure; work of breathing and spo₂.
Signs & symptoms
Congestion or pleuritic symptoms may resemble infection without a clear infectious pattern.
Focused exam
Observe position, speech, accessory-muscle use, pattern, depth, and chest symmetry; Auscultate all lung fields and reassess after movement or treatment.
Brief pathophysiology
Heart failure can resemble cough / suspected respiratory infection through overlapping symptoms or referred physiology despite a different primary mechanism.
What the trend may show
Respiratory infection may impair oxygenation and trigger systemic illness. Older or immunocompromised patients may lack fever, so trend all four observations and mental status.
Respiratory rate (breaths/min)
Often risesTachypnea can be an early marker of respiratory or systemic illness.
Oxygen saturation (SpO₂)
May fallParenchymal disease can impair gas exchange; compare with baseline.
Temperature (°C)
May rise or fallFever is common, but normal or low temperature does not exclude serious infection.
Heart rate (bpm)
Often risesTachycardia may reflect fever, hypoxia, dehydration, or sepsis.
Front-load in the triage report
- Congestion or pleuritic symptoms may resemble infection without a clear infectious pattern.
- Onset and sputum?
- Fever or infectious exposure?
PEImportant alternative presentation
HPI
Clarify fever or infectious exposure; work of breathing and spo₂; lung sounds.
Signs & symptoms
Congestion or pleuritic symptoms may resemble infection without a clear infectious pattern.
Focused exam
Auscultate all lung fields and reassess after movement or treatment; Assess cough and sputum, lung sounds, focality, work of breathing, hydration, fever, chest pain, and infection risk.
Brief pathophysiology
PE can resemble cough / suspected respiratory infection through overlapping symptoms or referred physiology despite a different primary mechanism.
What the trend may show
Pulmonary embolism may have normal observations. Tachycardia, tachypnea, or hypoxemia increase concern; hypotension identifies hemodynamic compromise rather than being required for diagnosis.
Heart rate (bpm)
May riseTachycardia is common but neither sensitive nor specific.
Respiratory rate (breaths/min)
May riseTachypnea may be an early sign of increased ventilatory demand.
Oxygen saturation (SpO₂)
May fallHypoxemia may occur, but a normal saturation does not exclude PE.
Blood pressure (mmHg)
Often preservedHypotension suggests high-risk PE with obstructive shock.
Front-load in the triage report
- Congestion or pleuritic symptoms may resemble infection without a clear infectious pattern.
- Fever or infectious exposure?
- Work of breathing and SpO₂?
Findings that should escalate concern
- Hypoxemia
- Exhaustion
- Hemoptysis
- Signs of sepsis
- Hypoxia, severe work, confusion, shock, hemoptysis, immune compromise, or rapidly worsening symptoms raises concern for pneumonia or sepsis.
- Pneumonia or sepsis: Focal crackles, hypoxia, tachypnea, hypotension, or altered mentation.
Medication recognition
Continue the clinical pathway
Clinical and academic sources
Curated clinical guidance and peer-reviewed evidence supporting this presentation. Current BCEHS guidance, medical direction, and local policy remain authoritative for practice.
BCEHS Handbook — specific CPGs
Supporting clinical and academic evidence
- CEDIS Presenting Complaint List updateCanadian Association of Emergency Physicians
Presenting-complaint terminology and categorization context. It does not establish a prehospital “top 100” ranking.
- Surviving Sepsis Campaign: International Guidelines for Management of Sepsis and Septic Shock 2026Society of Critical Care Medicine and European Society of Intensive Care Medicine
Contemporary sepsis physiology, perfusion, and hemodynamic context. Hospital treatment recommendations do not replace BCEHS guidance.
- Suspected sepsis in people aged 16 or over: recognition, assessment and early managementNational Institute for Health and Care Excellence
Recognition, early assessment, monitoring, risk, and limitations of isolated observations in suspected adult sepsis.
- Guideline for oxygen use in adults in healthcare and emergency settingsBritish Thoracic Society
Peer-reviewed guidance for oxygen assessment, targets, delivery, and monitoring in acute illness.
- Diagnosis and Treatment of Adults with Community-acquired PneumoniaAmerican Journal of Respiratory and Critical Care Medicine · 2019
Pneumonia diagnosis, severity, respiratory compromise, and evidence-based management context.