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Episode Overview

In this episode of the Prehospital Paradigm Podcast, hosts Scott Wildenheim, Dr. John Hill, and guest Suzy Forgues discuss one of the most important clinical skills in EMS and emergency medicine: differential diagnosis.

The conversation explores how EMS providers can move beyond rote protocol-driven care and develop critical thinking skills that allow them to consider multiple potential causes for a patient's presentation. The group emphasizes avoiding tunnel vision, maintaining broad differentials, and recognizing life-threatening conditions while continually reassessing patients.

Key Topics Discussed

What Is Differential Diagnosis?

• The process of considering multiple possible causes for a patient's symptoms.

• Why providers should avoid locking onto the first diagnosis that seems obvious.

• The importance of asking, "What else could this be?"

• The concept that the most commonly missed diagnosis is often "the second diagnosis."

Evolution of EMS Clinical Thinking

• Transition from algorithm-driven medicine toward clinical reasoning.

• How modern EMS education increasingly focuses on assessment and critical thinking.

• Why EMS providers should think diagnostically even if they are not making definitive diagnoses.

• The value of post-call follow-up and run review in developing clinical judgment.

The Importance of History and Physical Assessment

• Why quality questions matter more than quantity.

• Using a patient's story to narrow a differential diagnosis.

• How assessment findings help support or eliminate potential causes.

• The importance of understanding why specific questions are being asked.

Clinical Presentations Reviewed

Chest Pain Differential

Potential causes discussed:

• STEMI/NSTEMI

• Pulmonary embolism (PE)

• Aortic dissection

• Tension pneumothorax

• Esophageal rupture

• Pericardial tamponade

• Gastroesophageal reflux disease (GERD)

• Musculoskeletal pain

• Anxiety and panic disorders

Key takeaways:

• Chest pain should never be dismissed.

• Consider both common and life-threatening causes.

• Use ECG findings, vital signs, risk factors, and patient history to narrow possibilities.

• Anxiety should remain a diagnosis of exclusion.

Altered Mental Status Differential

Potential causes discussed:

• Hypoglycemia

• Stroke

• Seizure/postictal state

• Sepsis

• Hypoxia

• Hypercarbia

• Head injury

• Overdose/toxic exposure

• Shock

• Electrolyte and metabolic abnormalities

Key takeaways:

• Blood glucose remains a critical assessment.

• End-tidal CO₂ monitoring has become an important diagnostic tool.

• Understanding the patient's baseline mental status is essential.

• Sepsis and infection are common causes of confusion in elderly patients.

Abdominal Pain Differential

Potential causes discussed:

• Abdominal aortic aneurysm (AAA)

• Ectopic pregnancy

• GI bleeding

• Bowel obstruction

• Constipation

• Myocardial infarction presenting as abdominal pain

• Diabetic ketoacidosis (DKA)

• Testicular torsion

• Ovarian torsion

• Gastroenteritis

Key takeaways:

• Abdominal pain often has a broad differential.

• Atypical presentations of cardiac disease are common.

• Physical examination and thorough history remain critical.

• Sometimes neither EMS nor the emergency department can immediately identify the exact cause.

Shortness of Breath Differential

Potential causes discussed:

• Asthma

• COPD exacerbation

• CHF/pulmonary edema

• Pneumonia

• Pulmonary embolism

• Acute coronary syndrome

• Pneumothorax

• Anaphylaxis

• Sepsis

• DKA/metabolic acidosis

• Toxic inhalation

• Foreign body airway obstruction

• Anxiety

Key takeaways:

• Approach respiratory patients systematically.

• Assess whether lung sounds are "wet," "tight," or clear.

• Medication history often provides valuable clues.

• Orthopnea and sleeping position can help identify heart failure exacerbations.

Syncope and Near Syncope

Potential causes discussed:

• Vasovagal syncope

• Orthostatic hypotension

• Dehydration

• Dysrhythmias

• Acute coronary syndrome

• Pulmonary embolism

• GI bleeding

• AAA

• Ectopic pregnancy

• Seizure

• Stroke/TIA

• Hypoglycemia

• Medication effects

• Postural Orthostatic Tachycardia Syndrome (POTS)

Red flags include:

• Exertional syncope

• Associated chest pain

• Shortness of breath

• Palpitations

• Abnormal ECG findings

• Hypotension

• Significant cardiac history

Clinical Tools and Technology

Discussion includes:

• 12-lead ECG interpretation

• Stroke assessment scales

• NIH Stroke Scale education

• End-tidal CO₂ monitoring

• Pulse oximetry

• Emerging role of prehospital ultrasound

• Value of serial reassessments

The panel emphasizes that diagnostic technology should support, not replace, strong assessment skills.

Common Cognitive Errors in EMS

Anchoring

Fixating on the first diagnosis and ignoring other possibilities.

Confirmation Bias

Searching only for evidence that supports an initial impression.

Premature Closure

Ending the diagnostic process too early.

Diagnostic Momentum

Accepting someone else's diagnosis without independent assessment.

Normalization of Deviance

Accepting abnormal findings because they are commonly encountered.

Educational Pearls

• Patients do not read textbooks.

• Common presentations may hide uncommon diagnoses.

• EMS providers should continuously reassess their differential diagnosis.

• History-taking and physical examination remain foundational skills.

• The goal is not always to identify the exact diagnosis, but to recognize and treat life threats.

• A broad differential improves patient safety.

• Clinical reasoning improves through repetition, education, and case review.

Takeaway Message

Strong EMS clinicians develop the habit of continuously asking what else could explain a patient's presentation. By maintaining a broad differential diagnosis, avoiding cognitive bias, and combining assessment findings with patient history, providers improve both decision-making and patient outcomes. This episode reinforces that critical thinking is just as important as protocols and procedures in modern prehospital care.