CRACKCast E025 – Dyspnea

In CRACKCast, Podcast by Adam Thomas2 Comments

This episode of CRACKCast covers Rosen’s Chapter 25, Dyspnea. Dyspnea has a broad differential; to list them all would leave you short of breath. This episode covers an approach to dyspnea and the critical diagnoses to remember for this cardinal presentation.

Shownotes – PDF Here

Rosen’s in Perspective

“Dyspnea”: uncomfortable sensation of breathlessness, “Air hunger”

  • Non-specific spectrum from mild disease to severe disease
  • May be referred to as different terms

Other terms to know:

Tachypnea − RR > normal >45-60 bpm in neonates; to >18 bpm in adults

Hyperpnea – Greater than normal minute ventilation to meet metabolic requirements

Hyperventilation – Minute ventilation exceeding metabolic demand

-> ABG showing normal PaO2

+ Uncompensated respiratory alkalosis

+ Elevated pH

Dyspnea on Exertion (DOE) – Dyspnea provoked by physical effort

Orthopnea – Dyspnea in a recumbent position

Paroxysmal Nocturnal Dyspnea (PND) – Sudden SOB at night

Pathophysiology

  • Normal breathing controlled by:
    • Centrally by the respiratory centres in the medulla oblongata
    • Peripherally by the chemoreceptors in the carotid bodies
    • Mechanical centres in the diaphragm and skeletal muscles
  • Any imbalance in these sites leads to dyspnea – mechanism not fully understood

Perception of dyspnea relates to:

  • Increased lung resistance
    • COPD or Asthma
  • Increased respiratory drive
    • Severe hypoxemia, acidosis, centrally acting toxins, or CNS events

1) List 10 critical causes of dyspnea

First key question:

  • Is the dyspnea cardio-pulmonary OR toxic-metabolic?


CRITICAL CAUSES:

Pulmonary

  1. Airway obstruction
    a) Heimlich maneuver & direct laryngoscopy with McGill forceps
  2. Pulmonary embolism
  3. Non-cardiogenic pulmonary edema
  4. Anaphylaxis
  5. Respiratory failure
  6. Tension pneumothorax +/- flail chest
    a) Severe respiratory distress, hypoxia, hypotension
    b) Decreased breath sounds, oxygen desaturation

 Cardiac

  1. Pulmonary edema (due to CHF)
  2. Myocardial infarction
  3. Cardiac tamponade

Other

  1. Toxic ingestions (e.g. organophosphate ingestion)
  2. DKA
  3. Epiglottitis
  4. CO poisoning
  5. Acute chest syndrome (e.g. Sickle cell)

CVA / intracranial catastrophe

Wisecracks

1) Outline your approach to the acutely dyspneic patient

Management and disposition

  • Dyspnea requires simultaneous evaluation and management
    • Use the MOVIE approach and initiate empiric treatments based on:
      • Trauma
      • Anaphylaxis
      • Foreign body
      • Infectious causes
      • Cardiac causes (dysrhythmia, ischemic, CHF)
      • PE
      • Asthma / COPD

Signs & Ancillary Studies


Full set of vitals, patient’s general appearance, skin/nail findings

  • Neck, lung, chest, cardiac, extremities and neuro exam can assist with diagnosis
  • Tests to consider:
    • Vitals with SPO2 however know when it is unreliable
    • ABG
    • ECG
    • Beside U/S
    • CXR
    • Labs – rule out anemia, infection, electrolyte abnormalities, or renal failure
  • WBC is of little sensitivity or specificity
  • BNP, troponin, and D-dimer may be of some use
    • Soft tissue lateral neck – for upper airway processes
    • CT chest for intra-thoracic causes (PE, pneumonia, etc.)

2) Name at least 6 uncommon causes of dyspnea

  • Valvular heart disease
  • Cardiomyopathy
  • Mechanical interference (pregnancy, ascites, obesity, hiatal hernia)
  • Ruptured diaphragm
  • Thyrotoxicosis
  • Guillain-Barre syndrome
  • Tick paralysis
  • MS
  • ALS
  • Polymyositis
  • Porphyria

This episode was edited and uploaded by Colin Sedgwick (@colin_sedgwick)

(Visited 947 times, 1 visits today)
Adam Thomas

Adam Thomas

Adam Thomas is a MedEd re-purpose-r. He cofounded the CrackCast project to fill the obvious gap in current FOAMed. He is a true podcasting supporter, and finds it to be the best way he learns. Currently a resident in the FRCP program at the University of British Columbia.
Adam Thomas
- 2 days ago
Adam Thomas

Latest posts by Adam Thomas (see all)

Chris Lipp
Chris Lipp is one of the founding Fathers for CrackCast and an EM Resident in Victoria, BC. His interests are in sports, exercise, and wilderness medicine. When he isn’t out on one of his accidental 20km trail runs, you can find him jamming with friends, or outdoors, and reading Rosen’s…..
Chris Lipp

Latest posts by Chris Lipp (see all)