Shortness of breath, also known as dyspnea, is a common reason for patients to visit the Emergency Department.  Dyspnea is often caused by a pulmonary or cardiovascular condition, but it is important to remember that dyspnea can be due to endocrine conditions, toxicologic conditions, neurologic conditions, hematologic conditions, musculoskeletal conditions, and psychiatric conditions. 

The initial approach to all patients with shortness of breath involves the primary survey, or “ABCs” (Airway, Breathing, Circulation).  This first involves checking the patient for a patent airway.  A simple method to assess the airway is to ask the patient to speak and listen for the voice.  A muffled voice, the presence of stridor, hematemesis, or a lethargic patient are clues that a patent airway may not be present.  Problems with the airway, such as an obstructing foreign body, inflammation (i.e., epiglottitis, anaphylactic shock), or vocal cord dysfunction can certainly cause shortness of breath.  Endotracheal intubation may need to be performed before moving forward.  Breathing is assessed by evaluating the function of the lungs.  Steps include looking at how the patient is breathing (fast or slow), measurement of an SpO2 level, and auscultation of both lungs for wheezing, crackles, rhonchi, or distant or absent sounds.  A low oxygen level should be immediately addressed with supplemental oxygen before moving forward.  The patient’s breathing rate and lung sounds can be very helpful in discovering the diagnosis and guiding treatment.  Lastly, circulation should be assessed.  Check the heart rate, blood pressure, peripheral pulses, skin color and temperature, and evaluate for any sites of hemorrhage.  The presence of hypotension or tachycardia should be addressed appropriately based on the presumed cause.  After the primary assessment (“ABCs”) and initial treatment actions, a more detailed history and physical exam should be conducted. 

Pertinent causes of shortness of breath for the emergency practitioner to know are outlined in the chart below. 

This patient arrives to the Emergency department with shortness of breath, productive cough, and fever for 5 days.  On exam, the patient is febrile, tachycardic, and has a low SpO2 on room air.  The lung exam demonstrates focal rhonchi at the right base.  The chest X-ray demonstrates a consolidation at the right middle lobe that obscures the right heart boarder.  The consolidation is highlighted with a red star in the patient’s X-ray below.

Lung consolidations have multiple causes, including pneumonia, malignancy, heart failure, pulmonary emboli, and septic emboli from endocarditis.  Septic pulmonary emboli (Choice A) can present with cough, fever, and difficulty breathing, but often have multiple foci of consolidations on chest X-ray.  This patient has a single area of consolidation.  This patient also lacks the typical risk factors for septic emboli, like IV drug use, recent dental procedures, structural heart disease, or prosthetic heart valves.  An infected pleural effusion (Choice B), also known as an empyema, is shown as a blunted or hazy right costo-diaphragmatic angle.  This patient’s X-ray shows no fluid in both costo-diaphragmatic recesses to indicate the presence of a pleural effusion.  A pulmonary embolism (Choice D) often presents with clear lungs on auscultation and a normal chest X-ray.  However, if the pulmonary embolism progresses to a pulmonary infarct, a wedge-shaped opacity can be seen on the X-ray.  This patient’s X-ray lacks this finding.  The most likely cause for this patient’s symptoms is a right middle lobe pneumonia (Choice C).  She should receive IV fluids, antipyretics, supplemental oxygen, and IV antibiotics.