Differential Diagnosis for Noisy Breathing and Respiratory Distress

Immediate Assessment and Severity Stratification

The American College of Physicians recommends assessing airway, breathing, and circulation (ABC) first, measuring vital signs including respiratory rate, pulse rate, blood pressure, temperature, and oxygen saturation by pulse oximetry in all patients 1, 2
Patients with respiratory rate >30 breaths/min should be triaged as very urgent 1
The National Institute for Health and Care Excellence suggests using a recognized physiological "track and trigger" system such as the National Early Warning Score (NEWS) for initial assessment and monitoring 2
Document level of alertness, fluid status, presence of cyanosis, respiratory distress, and wheezing, though wheezing can be an unreliable indicator of airway obstruction 3, 4

Upper airway obstruction presents with dysphonia, inspiratory stridor, and monophonic wheezing loudest over the central airway 3, 4
Foreign body aspiration is characterized by sudden onset, often with choking history 3, 4
Epiglottitis is marked by acute onset, drooling, toxic appearance 3, 4
Laryngospasm is characterized by sudden onset, may follow airway manipulation or irritation 5
Vocal cord dysfunction mimics asthma but with inspiratory stridor and normal oxygen saturation 3, 4

COPD exacerbation presents with worsening breathlessness, increased sputum production, or change in sputum color in patients with known or suspected COPD 2
Patients >50 years who are long-term smokers with chronic breathlessness on minor exertion should be treated as having suspected COPD and require spirometric assessment 2
Asthma exacerbation is characterized by paroxysmal dyspnea with shortness of breath, often with dry cough mainly at night, frequently associated with allergies 3, 4
Assess severity using physical examination findings including level of alertness, ability to speak in full sentences, accessory muscle use, and presence of cyanosis 3, 4

Obtain arterial blood gas measurement on arrival, noting inspired oxygen concentration 1
Order chest radiograph as urgent investigation 1
Check arterial blood gases within 60 minutes of starting oxygen therapy 1
Target oxygen saturation of 88-92% using 24% Venturi mask at 2-3 L/min or 28% Venturi mask at 4 L/min to reduce mortality risk 1

For patients without risk of hypercapnic respiratory failure, target oxygen saturation is 94-98% 2
For patients with risk of hypercapnic respiratory failure (COPD, morbid obesity, chest wall deformities, neuromuscular disorders), target oxygen saturation is 88-92% pending blood gas results 1, 2
Administer nebulized bronchodilators on arrival and at 4-6 hourly intervals for COPD exacerbation 1
Administer inhaled bronchodilators (albuterol/salbutamol) immediately for patients with known asthma or COPD presenting with acute dyspnea and wheezing 2

Administering high-flow oxygen (>28%) to COPD patients before blood gas results are available can worsen hypercapnic respiratory failure 1, 2
Failing to recognize COPD in older smokers with chronic breathlessness 1
Assuming wheezing always indicates lower airway disease; upper airway obstruction can present with monophonic wheezing 3, 4
Overlooking cardiac causes of shortness of breath, particularly in women who may present with atypical symptoms 2