Determining the Cause

Pivotal Assessment	Findings
History

Acute Coronary Syndrome

**Congestive Heart Failure**
Acute decompensation of heart failure can lead to fluid buildup in the lungs, causing severe breathing difficulties[1][3].

## Pulmonary Causes

**Pulmonary Embolism**
A blood clot in the lungs can cause sudden, severe shortness of breath and is potentially fatal if not treated promptly[1][3][5].

**Pneumonia**
Severe cases of pneumonia can lead to respiratory failure and life-threatening dyspnea[1][3].

**Acute Asthma Exacerbation**
A severe asthma attack can cause extreme difficulty breathing and may be life-threatening if not managed quickly[1][3].

**Pneumothorax (Collapsed Lung)**
A sudden collapse of the lung can cause acute, severe shortness of breath[1][3].

## Other Causes

**Anaphylaxis**

**Carbon Monoxide Poisoning**

**Severe Anemia**

Citations:
[1] https://my.clevelandclinic.org/health/symptoms/16942-dyspnea
[2] https://www.medicalnewstoday.com/articles/314963
[3] https://www.webmd.com/lung/shortness-breath-dyspnea
[4] https://www.lung.org/lung-health-diseases/warning-signs-of-lung-disease/shortness-of-breath/learn-about-shortness-of-breath
[5] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5247680/
[6] https://www.brighamandwomens.org/lung-center/diseases-and-conditions/dyspnea-shortness-of-breath
[7] https://www.nhsinform.scot/illnesses-and-conditions/lungs-and-airways/shortness-of-breath/
[8] https://www.mayoclinic.org/symptoms/shortness-of-breath/basics/causes/sym-20050890

Pivotal Assessment	Findings
History
History
Physical Exam

Determining the cause of acute dyspnea (shortness of breath) requires a structured approach that integrates clinical history, physical examination, and diagnostic testing. Here's a step-by-step guide:

1. Initial Assessment:

Airway, Breathing, Circulation (ABCs) – ensure the patient is stable.
Vital Signs – especially respiratory rate, oxygen saturation, heart rate, blood pressure, and temperature.

2. Focused History:

Onset: sudden (e.g., PE, pneumothorax) vs gradual (e.g., pneumonia, CHF)
Associated Symptoms:
- Chest pain (e.g., PE, MI, pneumothorax)
- Cough, sputum, fever (e.g., pneumonia, bronchitis)
- Wheezing (e.g., asthma, COPD)
- Orthopnea, PND, leg swelling (e.g., CHF)
- Recent travel/immobility (e.g., DVT/PE)
- Known medical history (e.g., asthma, COPD, CHF, immunosuppression)

3. Physical Examination:

General appearance: distress, cyanosis, diaphoresis
Lung exam: wheezing, crackles, diminished breath sounds
Heart exam: murmurs, gallops, jugular venous distension
Extremities: edema, DVT signs
Mental status: altered sensorium may indicate hypoxia/hypercapnia

4. Initial Tests:

Pulse oximetry and ABG – assess oxygenation and ventilation
Chest X-ray (CXR): pneumothorax, pneumonia, pulmonary edema, pleural effusion
Electrocardiogram (ECG): MI, arrhythmia, right heart strain (suggestive of PE)
Labs:
- CBC: infection, anemia
- BMP: acidosis, electrolyte imbalance
- BNP/pro-BNP: suggestive of heart failure
- D-dimer: if PE is suspected and low/moderate risk
- Troponin: if MI is a concern

5. Bedside or Advanced Imaging:

Point-of-care ultrasound (POCUS):
- B-lines = pulmonary edema
- Pleural sliding absent = pneumothorax
- RV dilation = PE
CT Pulmonary Angiogram (CTPA): definitive for PE
Echocardiogram: heart failure, tamponade, pulmonary hypertension

6. Consider the Most Common Causes:

System	Common Acute Causes
Pulmonary	Asthma, COPD exacerbation, pneumonia, PE, pneumothorax, aspiration
Cardiac	CHF, acute MI, arrhythmia, cardiac tamponade
Other	Anemia, metabolic acidosis (DKA, sepsis), anxiety, upper airway obstruction

Mnemonic: “HORID PANT” for acute dyspnea:

Heart failure
Obstruction (upper airway)
Respiratory (COPD, asthma)
Infection (pneumonia)
Drug/medication or DKA
Pulmonary embolism
Anxiety
Neuromuscular weakness
Tension pneumothorax

Would you like a flowchart to visualize this process or an example case to walk through?