Acute Shortness of Breath (SOB): <2-3 Weeks

Our discussion assumes there are NO signs of life-threatening lack of oxygen.

Anyone who says they’ve recently begun to feel โ€œSOBโ€ may not be allowed inside a building without a Covid Test. But some patients need to be seen no matter what; every office or clinic should have its own mechanism, maybe in a designated exam room, maybe calling an ambulance.

Causes of Acute (Recent-Onset) Shortness of Breath (SOB)


โ€ข Myocardial Infarction (M.I.) xxx (heart attack)
โ€ข Angina (coronary artery xxxdisease)
โ€ข Heart Failure (HF)
โ€ข Anemia
โ€ข Early Shock (e.g. Sepsis)

โ€ข Covid-19
โ€ข Pulmonary Embolism (PE)
โ€ข Pneumonia
โ€ข Bronchospasm (from Viral xxInfection, Asthma, or COPD)
โ€ข Uncommon Lung Conditions

โ€ข Anaphylaxis (allergy)
โ€ข Obstruction in Upper Airway  


โ€ข Rare Causes

Hereโ€™s how we approach the patient with Acute SOB which doesnโ€™t appear imminently life-threatening (after establishing itโ€™s what I call  โ€œTrueโ€ SOB (always feels worse with exertion) See the link for an explanation.

New SOB is often Bronchospasm (like Asthma, Bronchitis).  But before we make that diagnosis, we consider other more serious diseases [see full text for in-depth explanations].

1.  Maybe a Heart Attack? Seek risk factors & associated symptoms of Acute M.I. or Angina (also see Diagnosing Coronary Artery Disease):

  • Risks: M >40, F >45; smoker; hypertension; diabetes; family history; high cholesterol
  • Other Symptoms at time of SOB: chest pain, nausea; cold sweat; lightheaded
  • Call 911 if thinking M.I. or progressive unstable Angina (& give an aspirin) (see Diagnosing Coronary Artery Disease for what they do in ER)
  • Obtain EKG.  If thinking stable Angina, order stress tests (see Diagnosing Coronary Artery Disease)
  • May give intensive medical treatment while awaiting stress test results

2.  Think about a Pulmonary Embolism (PE):

  • Inquire about both: 1) very sudden onset of SOB; and 2) risk factors for PE:
  • Send to ER if suspicious, for d-Dimer blood test: if high โ†’ CT-Angiogram.

3.  Look for evidence of Heart Failure (especially among older persons)

  • Canโ€™t sleep lying flat, wake up gasping for breath, swollen feet, weight increase, rales in both lungs (heard by stethoscope), certain findings on heart exam
  • Manage in ER if very recent onset (i.e. unstable)
  • If stable: Order certain labs (blood count, kidney tests, liver tests, BNP)
  • Order an EKG & esp. an echocardiogram
  • Maybe start treatment pending results
  • If diagnose โ€œHeart Failure,โ€ must seek a cause (always ask, “Why?”)
  • Young Persons may get Heart Failure from viruses: Myocarditis (maybe misdiagnosed as “Asthma” )

4.  Consider Pneumonia: fever, cough, maybe a patch of rales on lung exam.

  • Get a Chest X-Ray

5. Don’t Forget other potentially serious conditions if symptoms began within 1-2 days:

  • Uncommon Upper Airway Disease (stridor heard by stethoscope) โ†’ best managed in ER
  • Sepsis (there’s almost always fever) โ†’ fever + change in vital signs lying to standing โ†’ to ER
  • Acute Anemia โ†’ Obtain CBC; if also change in vital signs lying to standing โ†’ to ER
  • Especially donโ€™t forget rare Anaphylaxis
    • wheezing or stridor (lung sounds), with specific criteria including hives, swollen lips / face / throat, itching, classic exposure, vomiting/abdominal pain, rapid heart rate, low blood pressure.
    • Needs epinephrine stat (= ASAP)

6.  Repeat the test for Covid-19 in 2-3 days, especially if other symptoms (fever, body aches, cough, loss of smell). Isolate in the meantime.

Finally  —  If none of the above seem likely, we PROBABLY decide to diagnose Bronchospasm — i.e. Viral Infection (Influenza, etc.) / Asthma / COPD Exacerbation, because:

  • Patient doesn’t have a fever (or if fever, doesn’t seem like pneumonia)
  • We hear wheezes or rhonchi with our stethoscope; AND / OR
  • Thereโ€™s a long expiratory phase when listening with stethoscope
  • Thereโ€™s some sort of cough.

If we diagnose โ€œBronchospasmโ€, we treat as such — with inhalers, NOT antibiotics (unless a longtime smoker with new-onset green sputum). See medicines for Asthma. See also Acute Cough.

BUT, for a patient with recent-onset True SOB who clinically does NOT convincingly seem to have bronchospasm (no cough, normal lung exam), at a minimum we should order:

  • Complete Blood Count (for Anemia, infection) and Chest X-Ray (CXR).ย  The CXR will easily identify a number of items on the list of โ€œRare Causes.โ€ย  See link for consideration of other possibilities
  • BNP (blood test) to rule out Heart Failure (for anyone, but especially older persons)
  • Other basic lab tests for the variety of causes
  • EKG, only helpful if abnormal (EKG can be normal with heart attack & anything else)
  • Other work-up (echocardiograms, pulmonary function tests, etc.) discussed under our topic Chronic SOB, but may obtain sooner if patient’s SOB appears bad.

See also Acute Shortness of Breath — Full Text for more in-depth explanations and discussions.

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