Dyspnea, Emergency Medicine

Basics

Description

- Upper airway: - Epiglottitis - Laryngeal obstruction - Tracheitis or tracheobronchitis - Angioedema

- Abdominal compression: - Ascites - Pregnancy - Massive obesity

- Psychogenic: - Other: - Altitude - Anaphylaxis - Anemia

- Cardiovascular: - S3 gallop - Murmur - Jugular venous distention

- Signs of acute distress: - Altered mental status - Cyanosis - Respiratory rate - Retractions suggest severe disease

- Listen for abnormal lung sounds: - Stridor - Rales - Wheezing - Decreased breath sounds

- End tidal CO2: - Quickly gives hint of PaCO2 - Waveform can give clue to etiology

- BiPAP in alert patients: - Contraindications: - Cardiac instability - Suspicion of upper airway obstruction - Inability to protect airway - Upper GI bleeding - Status epilepticus

- Based on underlying etiology - Antibiotics and fluid for pneumonia - CPAP and diuretics for CHF - Bronchodilators and steroids for asthma - Aspirin, heparin, and lyrics/cath lab for MI - Other treatments as necessary for other etiologies

- Patients should be told not to smoke while short of breath and to try to quit to help with some of the causes, as well as to prevent others from getting worse. - The patient should return for any of the following problems: - No improvement or worsening in 24 hr - New chest pain, pressure, squeezing, or tightness - Shaking chills, or a fever >102 пїЅF - New or worsening cough or wheezing - Abdominal (belly) pain, vomiting, severe headache - Dizziness, confusion, or change in behavior - Any serious change in symptoms, or any new symptoms that are of concern

Inability to breathe comfortably пїЅ

Describes a symptom of many possible underlying diseases
Is different from signs of increased work of breathing
Usually an unconscious activity, dyspnea is the subjective sensation of breathing, from mild discomfort to feelings of suffocation.
Dyspnea comes from the Greek word for "hard breathing."пїЅ
Often described as "shortness of breath"пїЅ
Common presenting complaint seen in 3.5% of ED visits
Caused by difficulties in maintaining homeostasis with respect to gas exchange and acid-base status
Dyspnea usually reflects an impairment in ventilation, perfusion, metabolic function, or CNS drive.
Mechanisms that control breathing:Control centers:Brainstem and cerebral cortex affect both automatic and voluntary control of breathing.Chemo, stretch, and irritant sensors:CO2 receptors located centrally and PO2 receptors located peripherally.Mechanoreceptors lie in respiratory muscles and respond to stretch.Intrapulmonary mechanoreceptors respond to chemical irritation, engorgement, and stretch.Effectors of respiratory center output are in the respiratory muscles and respond to central stimulation to move air in and out of the thoracic cavity.Motor-sensory control of the diaphragm and muscles of respiration are controlled by C3-C8 nerves and T1-T12 nerves.
Derangements of any of these neurosensory pathways produces dyspnea:Many etiologies for the sensation of dyspnea are due to the complex nature of mechanisms that control breathing.

Etiology

Upper airway:EpiglottitisLaryngeal obstructionTracheitis or tracheobronchitisAngioedema
Pulmonary:Airway massAsthmaBronchitisChest wall traumaCHFDrug-induced conditions (e.g., crack lung, aspirin overdose)EffusionEmphysemaLung cancerMetastatic diseasePneumoniaPneumothoraxPulmonary embolismPulmonary HTNRestrictive lung disease
Cardiovascular:ArrhythmiaCoronary artery diseaseIntracardiac shuntLeft ventricular failureMyxomaPericardial diseaseValvular disease
Neuromuscular:CNS disordersMyopathy and neuropathyPhrenic nerve and diaphragmatic disordersSpinal cord disordersSystemic neuromuscular disorders
Metabolic acidosis:SepsisDKAAKARenal failureProfound thiamine deficiency
Toxic:MethemoglobinemiaSalicylate poisoningCellular asphyxiants:Carbon monoxideCyanideHydrogen sulfideSodium azideToxic alcohols
Abdominal compression:AscitesPregnancyMassive obesity
Psychogenic:
Other:AltitudeAnaphylaxisAnemia

Most common diagnoses in elderly patients presenting to the ED with dyspnea:Decompensated heart failurePneumoniaCOPDPulmonary embolismAsthma

Common conditions in differential diagnosis for age <2 yr:AsthmaCroupCongenital anomalies of the airwayCongenital heart diseaseForeign-body aspirationNasopharyngeal obstructionShock

Diagnosis

Signs and Symptoms

Difficult, labored, or uncomfortable breathing
Upper airway:StridorUpper-airway obstruction
Pulmonary:TachypneaAccessory muscle useWheezingRalesAsymmetric breath soundsPoor air movementProlonged expiratory phase
Cardiovascular:S3 gallopMurmurJugular venous distention
CNS:Altered levels of consciousness
General:Diaphoretic/cool vs. hot/dry skinPallorUpright patient positionClubbingCyanosisEdemaKetotic breath odor

History

Previous history of dyspnea
Time course, abruptness of onset, triggers, and severity
History of stridor or wheezing
Exercise (activity) tolerance
Medications and recent compliance
Exposure to allergens
Past medical history
Associated symptoms:Chest painFeverCoughHemoptysis

Physical Exam

Signs of acute distress:Altered mental statusCyanosisRespiratory rateRetractions suggest severe disease
Listen for abnormal lung sounds:StridorRalesWheezingDecreased breath sounds

Essential Workup

Pulse oximetry:May be falsely elevated due to increased ventilation or carbon monoxide
End tidal CO2:Quickly gives hint of PaCO2Waveform can give clue to etiology
CXR:For diagnosis of pulmonary conditionsAssess heart size and evidence of CHF
ABG:OxygenationCalculate arterial-alveolar gradient:A-a (at sea level) = 150 - (PO2 - PCO2)/0.8, normal 5-20Assess degree of acidosis

Diagnosis Tests & Interpretation

Lab

CBC:Evaluation for anemiaNeutrophil count helpful in evaluation of infectious processes
Electrolyte, BUN, creatinine, glucose:Consider when specific metabolic derangements are suspectedB-type natriuretic peptide may be elevated in CHF
Toxicology screen
Methemoglobin/carboxyhemoglobin level
Thyroid function tests
D-dimer (ELISA):Useful for excluding pulmonary embolus if normal

Imaging

Chest x-ray for infiltrate, effusion, pneumothorax, or vascular consolidation
Ventilation-perfusion scan or CT pulmonary angiogram for suspected pulmonary embolism
Soft tissue neck radiograph or fiberoptic visualization for suspected upper airway obstruction

Diagnostic Procedures/Surgery

EKG for suspected myocardial ischemia, CHF, suspected pericardial effusion/tamponade
Peak expiratory flow/spirometry to assess for reactive-airway disease
Tensilon test for suspected myasthenia gravis

Differential Diagnosis

Anticholinergic or adrenergic toxidrome
Thyroid storm
Munchausen syndrome

Treatment

Pre-Hospital

Place all patients on supplemental oxygen, pulse oximetry, end tidal CO2, and cardiac monitor.
Initiate therapy for suspected cause of dyspnea when indicated:
Utilize advanced airways in the face of impending respiratory failure.

Initial Stabilization/Therapy

ABCs
Immediate intubation for impending respiratory arrest:Altered mental statusUnstable vital signs
BiPAP in alert patients:Contraindications:Cardiac instabilitySuspicion of upper airway obstructionInability to protect airwayUpper GI bleedingStatus epilepticus

Ed Treatment/Procedures

Based on underlying etiologyAntibiotics and fluid for pneumoniaCPAP and diuretics for CHFBronchodilators and steroids for asthmaAspirin, heparin, and lyrics/cath lab for MIOther treatments as necessary for other etiologies
Palliative care with opiates is indicated for the relief of dyspnea in terminally ill patients.

Follow-Up

Disposition

Admission Criteria

Assisted ventilation
Hypoxia
A-a gradient >40
Medical condition requiring hospital therapy

Discharge Criteria

Adequate oxygenation
Stable medical illness that can be managed as outpatient
Adequate ambulatory pulse ox

Issues for Referral

Based on suspected underlying etiology пїЅ

Follow-Up Recommendations

Patients should be told not to smoke while short of breath and to try to quit to help with some of the causes, as well as to prevent others from getting worse.
The patient should return for any of the following problems:No improvement or worsening in 24 hrNew chest pain, pressure, squeezing, or tightnessShaking chills, or a fever >102 пїЅFNew or worsening cough or wheezingAbdominal (belly) pain, vomiting, severe headacheDizziness, confusion, or change in behaviorAny serious change in symptoms, or any new symptoms that are of concern

Pearls and Pitfalls

Altered mental status is an indication for immediate airway management in a patient with severe dyspnea.
Dyspnea can and should be quantified.
Dyspnea and tachypnea may occur without a respiratory etiology because of metabolic derangement or a catastrophic CNS event.

Additional Reading

Camargo пїЅCA Jr, Rachelefsky пїЅG, Schatz пїЅM. Managing asthma exacerbations in the emergency department: Summary of the National Asthma Education and Prevention Expert Panel Report 3 guidelines for the management of asthma exacerbations. J Allergy Clin Immunol. 2009;124(2 suppl):S5-S14.
De Peuter пїЅS, Van Diest пїЅI, Lemaigre пїЅV, et al. Dyspnea: The role of psychological processes. Clin Psychol Rev. 2004;24(5):557-581.
Mahler пїЅDA, Selecky пїЅPA, Harrod пїЅCG, et al. American College of Chest Physicians consensus statement on the management of dyspnea in patients with advanced lung or heart disease. Chest. 2010;137(3):674-691.
Stenton пїЅC. The MRC breathlessness scale. Occup Med (Lond). 2008;58:226-227.
Weintraub пїЅNL, Collins пїЅSP, Pang пїЅPS, et al., Acute heart failure syndromes: Emergency department presentation, treatment, and disposition: Current approaches and future aims: A scientific statement from the American Heart Association. Circulation. 2010;122:1975-1996.

Codes

ICD9

786.05 Shortness of breath
786.07 Wheezing
786.09 Other respiratory abnormalities
786.02 Orthopnea
786.06 Tachypnea
786.7 Abnormal chest sounds

ICD10

R06.00 Dyspnea, unspecified
R06.02 Shortness of breath
R06.2 Wheezing
R06.01 Orthopnea
R06.09 Other forms of dyspnea
R06.0 Dyspnea
R06.82 Tachypnea, not elsewhere classified
R09.89 Other specified symptoms and signs involving the circulatory and respiratory systems

SNOMED

267036007 Dyspnea (finding)
56018004 Wheezing (finding)
62744007 Orthopnea (finding)
271823003 Tachypnea (finding)
48409008 Respiratory crackles (finding)