Question Of The Day #81

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 presents to the Emergency Department with 1 day of acute onset shortness of breath with pleuritic chest pain. Her exam shows tachycardia, tachypnea, a normal glucose level, and clear lungs bilaterally.  The chest X-ray provided shows no acute abnormalities.  Pneumothorax (Choice A) can present as acute onset shortness of breath with pleuritic chest pain, but the chest X-ray shows no signs of pneumothorax.  Diabetic Ketoacidosis (Choice B) can cause shortness of breath, and this patient has a history of diabetes.  However, the patient lacks other symptoms of this condition such as hyperglycemia (often glucose >250mg/dL (13.8mmol/L)), polydipsia, polyphagia, polyuria, or vomiting.  This makes DKA an unlikely diagnosis. Pneumonia (Choice D) is also unlikely as there is no fever, no cough, and no infiltrate seen on the chest X-ray provided.  Pulmonary Embolism (Choice C) is the most likely diagnosis and the correct answer.

The most common presenting symptom in pulmonary embolism (PE) is shortness of breath.  Other symptoms seen in PE include chest pain worsened by deep inspiration, unilateral leg swelling, hemoptysis, and fever.  Risk factors for PE include immobility, recent surgery or hospitalization, trauma, or hypercoagulable states (malignancy, estrogen use, Factor V Leiden mutation, antiphospholipid syndrome).  Common signs of PE on physical examination include tachycardia (common), fever (less common), and sometimes hypotension in a massive PE causing obstructive shock.  The gold standard for PE diagnosis is CT pulmonary angiography, but D-dimer blood testing, bedside ultrasound, and other tests can be useful in PE diagnosis.  The mainstay of treatment in PE is anticoagulation.  Unfractionated heparin and low molecular weight heparin are equally effective in PE.  Surgical treatment (embolectomy) and thrombolysis (alteplase) are other treatment options fo larger PEs.