Shortness of breath (dyspnea) is one of the most urgent and alarming symptoms in medicine. It can be caused by mild, self-limited problems or severe, life-threatening emergencies like pulmonary embolism (PE), pneumothorax (PTX), pneumonia, asthma attack, or heart failure.
Your uploaded chart organizes SOB using:
- Red flags
- Major life-threatening causes
- Workup and treatments
- PERC rule
- Respiratory failure indicators
This article explains everything in a clear, academic, exam-oriented style.
Red Flags in Shortness of Breath
These symptoms suggest a serious or life-threatening cause:
Red Flags
- History of intubation
- Sudden onset
- Chest pain
- Fever
- Cough
- Leg swelling or leg pain
- Use of oral contraceptives (OCPs)
- Recent surgery
- Cancer
- Hemoptysis
- Immunocompromised status
When red flags are present, evaluate for PE, CHF, pneumonia, cancer-related issues, or pneumothorax.
Major Life-Threatening Causes of SOB (Chart Breakdown)
Your chart highlights six main emergency causes:
1. CHF / ACSLet’s discuss each in detail.
A. Congestive Heart Failure (CHF) / Acute Coronary Syndrome (ACS)
History & Exam Clues
- Tripod position
- Rales (crackles)
- Leg edema
- Jugular venous distention (JVD)
Diagnostics
- CXR
- BNP (Brain natriuretic peptide)
- Evaluate for MI/ischemia
Treatment
- Nitrates
- Lasix (furosemide)
- ACE-inhibitors
- BiPAP?
B. COPD / Asthma
History & Exam Clues
- Wheezing
- Tobacco use
- Prior exacerbations
Diagnostics
- Clinical, CXR
- Rule out pneumonia or pneumothorax
Treatment
- Nebulized bronchodilators
- Steroids
- ± Antibiotics for COPD exacerbation
SICK patient?
- Give magnesium
- Epinephrine (if severe)
- Consider BiPAP
- Consider tubing (intubation)
C. Pneumonia
History & Exam Clues
- Fever
- Sputum
- Dyspnea
Workup
- Clinical
- Chest X-ray
Treatment
Depends on severity (CURB-65 scoring):
Outpatient
Azithromycin (often first choice)Inpatient
Ceftriaxone + AzithromycinHospital-acquired
Cefepime + Vancomycin + AzithromycinD. Anaphylaxis
(Consider angioedema—also life-threatening)
History & Exam Clues
- Sudden onset
- Chest tightness
- Exposure to allergen
- OCP use (rare connection)
- Tobacco (less relevant clinically)
Diagnostics
- Clinical diagnosis
- ABCs priority
Treatment
- Epinephrine — first line
- Steroids + diphenhydramine + H2 blocker
- Nebulized bronchodilators
If patient is worsening → prepare for intubation ("Tube? Crike?")
E. Pulmonary Embolism (PE)
History & Exam Clues
- Sudden onset SOB or chest pain
- OCP use
- DVT symptoms
- Post-surgery
- Immobility
- Cancer
- Smoking
Diagnostics
Use validated tools:
- PERC rule (to rule out PE if low risk)
- D-dimer
- CT-Angiogram
- OR V/Q scan if pregnant or unable to tolerate contrast
Treatment
- Enoxaparin
- Heparin (if high creatinine or pregnant)
- Oral Xa inhibitors
Unstable patient?
Use tPA (systemic thrombolysis).
F. Pneumothorax (PTX)
History & Exam Clues
- Sudden onset
- Chest pain
- Absent breath sounds
- Trauma
- Tall, thin male
- Tobacco use
Diagnostics
CXR or bedside ultrasound
- Look for lack of lung sliding
Treatment
- Needle decompression
- Pigtail catheter
- Chest tube
G. Anxiety (Diagnosis of Exclusion)
History & Exam Clues
- Tingling
- Carpopedal spasm
- Hyperventilation history
- No red flags
Diagnostics
ExclusionTreatment
- Reassurance
- Breathing coaching
- Calm environment
PERC Rule (Pulmonary Embolism Rule-out Criteria)
(From the chart)
PE risk is <2% if all criteria are negative:
- Age < 50
- HR < 100
- Oxygen ≥ 94%
- No hemoptysis
- No estrogen (OCP) use
- No recent trauma or surgery
- No prior DVT/PE
- No signs of DVT on exam
If ALL are negative → PE ruled out without D-dimer.
Respiratory Failure Indicators (from chart)
Respiratory failure is present when the patient is:
“Tiring out”
or
Hypoxic OR high CO₂ (poor ventilation)
Treatment
- BiPAP
- Intubation
Important
Altered mental status (AMS) is a contraindication to BiPAP because of aspiration risk.
Documentation Essentials (Chart-Based)
Past Medical History
- Asthma, COPD, CHF
- Tobacco pack-years
- Prior hospitalizations
- Home oxygen
- Prior pneumonias
- Recent intubations
- DVT/PE risk factors
- Recent surgeries
- Cancer
HEENT
- Pharynx and tonsils
- Uvula not swollen
- Stridor
Neck
JVDLungs
- Wheezing (COPD/asthma)
- Crackles (CHF)
- Rhonchi (pneumonia)
- Clear lungs (bronchitis)
- Asymmetry (PTX)
Extremities
- Leg edema
- Signs of DVT (Homans’ sign, swelling, warmth, tenderness)
Quick Summary Table
| Cause | Key Clues | Diagnosis | Treatment |
|---|---|---|---|
| CHF/ACS | Rales, edema, JVD | CXR, BNP | Nitrates, Lasix, ACE-I, BiPAP |
| COPD/Asthma | Wheeze | Clinical/CXR | Nebs, steroids, ABx? |
| Pneumonia | Fever, sputum | CXR | Azith / Ceftriaxone + Azith |
| Anaphylaxis | Sudden SOB | Clinical | Epi, steroids, antihistamines |
| PE | Sudden SOB/CP | PERC, D-dimer, CT-A | Anticoagulation |
| PTX | Absent breath sounds | CXR/US | Needle → chest tube |
| Anxiety | Tingling/spasm | Exclusion | Reassure |
High-Yield Clinical Pearls
- Sudden SOB + chest pain = PTX or PE until proven otherwise
- Fever + sputum + rales = Pneumonia
- Wheezing + tobacco = COPD exacerbation
- SOB with leg swelling = DVT → PE risk
- “Tiring out” is the most important sign of respiratory failure
- Intubate early in anaphylaxis, angioedema, or exhaustion
- Clear lungs with hypoxia? Think PE
FAQs About Shortness of Breath
1. What is the most dangerous cause of sudden shortness of breath?
PE, pneumothorax, or severe anaphylaxis.
2. When does SOB require a CT scan?
When evaluating suspected pulmonary embolism.
3. Why is BiPAP dangerous in altered patients?
They cannot protect their airway → aspiration risk.
4. What is the difference between wheezing and stridor?
- Wheezing → lower airway (asthma, COPD)
- Stridor → upper airway (anaphylaxis, obstruction)
5. When should asthma patients be intubated?
When they are tiring, hypoxic, or cannot maintain ventilation.
6. How do you differentiate pneumonia from bronchitis?
Pneumonia: fever + crackles + infiltrates on CXR
Bronchitis: normal CXR
