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Emergency Medicine

The medical specialty concerned with the care of illnesses or injuries requiring immediate medical attention.

✓ Introduction to Emergency Medicine

✓ Introduction to Emergency Medicine is a clinical topic covering pathophysiology, diagnosis, evidence-based treatment, and patient care.

Key points: Core principles, practical applications, and advanced concepts that build deep understanding.

✓ Cardiac Emergencies Basics

✓ Cardiac Emergencies Basics is a clinical topic covering pathophysiology, diagnosis, evidence-based treatment, and patient care.

Key points: Core principles, practical applications, and advanced concepts that build deep understanding.

✓ Trauma Basics

✓ Trauma Basics is a clinical topic covering pathophysiology, diagnosis, evidence-based treatment, and patient care.

Key points: Core principles, practical applications, and advanced concepts that build deep understanding.

✓ Stroke Basics

✓ Stroke Basics is a clinical topic covering pathophysiology, diagnosis, evidence-based treatment, and patient care.

Key points: Core principles, practical applications, and advanced concepts that build deep understanding.

✓ Toxicology Basics

✓ Toxicology Basics is a clinical topic covering pathophysiology, diagnosis, evidence-based treatment, and patient care.

Key points: Core principles, practical applications, and advanced concepts that build deep understanding.

✓ Airway Management Basics

✓ Airway Management Basics is a clinical topic covering pathophysiology, diagnosis, evidence-based treatment, and patient care.

Key points: Core principles, practical applications, and advanced concepts that build deep understanding.

✓ Shock Basics

✓ Shock Basics is a clinical topic covering pathophysiology, diagnosis, evidence-based treatment, and patient care.

Key points: Core principles, practical applications, and advanced concepts that build deep understanding.

✓ Anaphylaxis Basics

✓ Anaphylaxis Basics is a clinical topic covering pathophysiology, diagnosis, evidence-based treatment, and patient care.

Key points: Core principles, practical applications, and advanced concepts that build deep understanding.

✓ Burns Basics

✓ Burns Basics is a clinical topic covering pathophysiology, diagnosis, evidence-based treatment, and patient care.

Key points: Core principles, practical applications, and advanced concepts that build deep understanding.

✓ Environmental Emergencies Basics

✓ Environmental Emergencies Basics is a clinical topic covering pathophysiology, diagnosis, evidence-based treatment, and patient care.

Key points: Core principles, practical applications, and advanced concepts that build deep understanding.

✓ Emergency Ethics Basics

✓ Emergency Ethics Basics is a clinical topic covering pathophysiology, diagnosis, evidence-based treatment, and patient care.

Key points: Core principles, practical applications, and advanced concepts that build deep understanding.

✓ Emergency Medicine Careers

✓ Emergency Medicine Careers is a clinical topic covering pathophysiology, diagnosis, evidence-based treatment, and patient care.

Key points: Core principles, practical applications, and advanced concepts that build deep understanding.

✓ Advanced Emergency Medicine

✓ Advanced Emergency Medicine is a clinical topic covering pathophysiology, diagnosis, evidence-based treatment, and patient care.

Key points: Core principles, practical applications, and advanced concepts that build deep understanding.

✓ Cardiac Emergencies

✓ Cardiac Emergencies is a clinical topic covering pathophysiology, diagnosis, evidence-based treatment, and patient care.

Key points: Core principles, practical applications, and advanced concepts that build deep understanding.

✓ Trauma

✓ Trauma is a clinical topic covering pathophysiology, diagnosis, evidence-based treatment, and patient care.

Key points: Core principles, practical applications, and advanced concepts that build deep understanding.

✓ Stroke

✓ Stroke is a clinical topic covering pathophysiology, diagnosis, evidence-based treatment, and patient care.

Key points: Core principles, practical applications, and advanced concepts that build deep understanding.

✓ Toxicology

✓ Toxicology is a clinical topic covering pathophysiology, diagnosis, evidence-based treatment, and patient care.

Key points: Core principles, practical applications, and advanced concepts that build deep understanding.

✓ Airway Management

✓ Airway Management is a clinical topic covering pathophysiology, diagnosis, evidence-based treatment, and patient care.

Key points: Core principles, practical applications, and advanced concepts that build deep understanding.

✓ Shock

✓ Shock is a clinical topic covering pathophysiology, diagnosis, evidence-based treatment, and patient care.

Key points: Core principles, practical applications, and advanced concepts that build deep understanding.

✓ Anaphylaxis

✓ Anaphylaxis is a clinical topic covering pathophysiology, diagnosis, evidence-based treatment, and patient care.

Key points: Core principles, practical applications, and advanced concepts that build deep understanding.

✓ Burns

✓ Burns is a clinical topic covering pathophysiology, diagnosis, evidence-based treatment, and patient care.

Key points: Core principles, practical applications, and advanced concepts that build deep understanding.

✓ Environmental Emergencies

✓ Environmental Emergencies is a clinical topic covering pathophysiology, diagnosis, evidence-based treatment, and patient care.

Key points: Core principles, practical applications, and advanced concepts that build deep understanding.

✓ Emergency Ethics

✓ Emergency Ethics is a clinical topic covering pathophysiology, diagnosis, evidence-based treatment, and patient care.

Key points: Core principles, practical applications, and advanced concepts that build deep understanding.

✓ Emergency Medicine Research

✓ Emergency Medicine Research is a clinical topic covering pathophysiology, diagnosis, evidence-based treatment, and patient care.

Key points: Time complexity (Big-O), space complexity, correctness proof, and practical implementation trade-offs.

Key Clinical Formulas & Scores

Glasgow Coma Scale (GCS) — ED Triage Tool:
Eye: 4=spontaneous, 3=to speech, 2=to pain, 1=none
Verbal: 5=oriented, 4=confused, 3=inappropriate, 2=incomprehensible, 1=none
Motor: 6=obeys, 5=localizes, 4=withdraws, 3=flexion, 2=extension, 1=none
GCS ≤8 = severe brain injury → airway protection (intubation)
GCS 9-12 = moderate, GCS 13-15 = mild
HEART Score (Chest Pain — ED Risk Stratification):
H = History (highly suspicious=2, moderately=1, non-suspicious=0)
E = ECG (significant ST depression=2, non-specific=1, normal=0)
A = Age (≥65=2, 45-64=1, <45=0)
R = Risk factors (≥3 or known CAD=2, 1-2=1, 0=0)
T = Troponin (≥3x normal=2, 1-3x=1, <1x=0)
0-3: Low risk (0.9-1.7% MACE) — early discharge
4-6: Intermediate (12-16.6%) — observation, serial troponins
7-10: High risk (50-65%) — admit, early invasive strategy
Canadian Syncope Risk Score:
Predicts serious cause within 30 days
Points: Clinical judgement low risk=-3, pre-syncope=-1
Clinical predictors: (each -1 to +2)
• Trauma: +1
• Male sex: +1
• Acute coronary syndrome history: +2
• Valvular heart disease: +2
• Signs of CHF: +2
• Shortness of breath: +1
• SBP <90: +2
Score: ≤-3 = low risk (0.4%), -2 to 0 = low-intermediate (2.2%), ≥1 = high risk (7.5%)
Ottawa Ankle Rules (Ankle X-ray):
X-ray needed if ANY of:
• Bone tenderness at posterior edge of distal 6 cm of tibia
• Bone tenderness at posterior edge of distal 6 cm of fibula
• Inability to bear weight (4 steps) both immediately and in ED
Sensitivity: ~97-100% (misses 1-3% of fractures)
Sensitivity ~97-100% for clinically significant ankle fractures
Specificity: ~40-50% (reduces X-rays by ~30-40%)
Anaphylaxis Diagnostic Criteria (3 criteria):
1. Acute onset + skin/mucosal involvement + respiratory compromise or hypotension
2. Acute onset + ≥2 of: skin/mucosal, respiratory, hypotension, GI symptoms
3. Hypotension after exposure to known allergen
Treatment: IM epinephrine 0.3-0.5 mg (1:1000) anterolateral thigh — FIRST LINE
Adjuncts: H1 blocker (diphenhydramine), H2 blocker (ranitidine), corticosteroids, IV fluids
Observation: 4-6 hours (biphasic reaction risk)

Core Concepts

ACLS Cardiac Arrest Algorithm

Shockable rhythms (VF/pulseless VT): CPR → defibrillation (200J biphasic) → CPR 2 min → epinephrine 1mg IV/IO q3-5min → shock → CPR 2 min → amiodarone 300mg IV → shock → CPR 2 min → epinephrine → shock → amiodarone 150mg → continue. Non-shockable (PEA/asystole): CPR → epinephrine q3-5min → search for reversible causes (H's and T's: Hypovolemia, Hypoxia, H+/Hypo-Hyperkalemia, Hypothermia, Tension pneumothorax, Tamponade, Toxins, Thrombosis (pulmonary/coronary)). Post-ROSC: targeted temperature management (32-36°C × 24h), hemodynamic optimization, coronary angiography if STEMI.

Trauma Assessment (ATLS)

Primary survey (ABCDE): Airway (with c-spine protection), Breathing (ventilation), Circulation (hemorrhage control, 2 large-bore IVs), Disability (GCS, pupils), Exposure (undress completely, prevent hypothermia). Secondary survey: head-to-toe exam, AMPLE history (Allergies, Medications, Past medical history, Last meal, Events). FAST exam (Focused Assessment with Sonography in Trauma): free fluid in Morrison's pouch, splenorenal, pelvis, pericardium. Resuscitative thoracotomy for penetrating thoracic trauma with signs of life. Damage control surgery for severe hemorrhage (permissive hypotension, massive transfusion protocol 1:1:1 ratio).

Toxicology: Common Overdoses & Antidotes

Acetaminophen: N-acetylcysteine (NAC) within 8-10 hours (Rumack-Matthew nomogram). Opioids: naloxone 0.4-2 mg IV (short half-life, may need infusion). Benzodiazepines: flumazenil (generally contraindicated — seizure risk). Beta-blockers/CCB: glucagon, high-dose insulin, calcium. Tricyclic antidepressants: sodium bicarbonate (QRS >100). Organophosphates: atropine + pralidoxime. Cyanide: hydroxocobalamin. Iron: deferoxamine. Warfarin: 4-factor PCC (KCentra), vitamin K.

Clinical Case Studies

Case 1: STEMI with Cardiogenic Shock

Patient: 62-year-old male, severe crushing chest pain × 1 hour, diaphoretic, hypotensive. BP 82/50, HR 110, cool extremities, JVD, crackles bilaterally. ECG: ST elevation V1-V4, II, III, aVF. Troponin 45 ng/mL.

Diagnosis: Acute extensive STEMI with cardiogenic shock (Killip IV).

Management: (1) Aspirin 325mg, ticagrelor 180mg, heparin bolus. (2) Emergent cardiac cath lab activation (door-to-balloon <90 min). (3) Vasopressors: norepinephrine for MAP <65. (4) Intra-aortic balloon pump (IABP) or Impella for mechanical support if deteriorating. (5) PCI to culprit vessel (likely LAD + RCA/LCx multivessel). (6) Post-PCI: ICU, inotropic support (dobutamine), monitor for complications (arrhythmias, mechanical complications).

Case 2: Severe Sepsis from Pyelonephritis

Patient: 45-year-old female, fever 39.8°C, rigors, left flank pain, confusion × 12 hours. PMH: diabetes. BP 82/50, HR 130, RR 28, SpO₂ 90%. Lactate 4.8. UA: cloudy, WBC>100, nitrites+. CXR: clear.

Diagnosis: Septic shock from urosepsis (pyelonephritis). qSOFA = 3.

Management: (1) 30 mL/kg crystalloid bolus (3000 mL NS within 3 hours). (2) Blood cultures × 2, then piperacillin-tazobactam 4.5g IV within 1 hour. (3) Norepinephrine for MAP <65 after fluids. (4) Supplemental O₂, maintain SpO₂ ≥94%. (5) Urinary catheter for output monitoring (target >0.5 mL/kg/hr). (6) CT abdomen/pylvis to exclude obstruction/perinephric abscess if no improvement in 24-48 hours. (7) ICU admission.

Case 3: Opioid Overdose

Patient: 22-year-old male found unresponsive, cyanotic, RR 4/min, pinpoint pupils. Bystander reports heroin use. GCS 3 (E1 V1 M1).

Diagnosis: Opioid overdose with respiratory depression.

Management:

Practice Questions

Q1: A patient with chest pain has a HEART score of 2. What is the MACE risk and disposition?
A: Low risk (0.9-1.7% MACE). May be considered for early discharge with outpatient follow-up and stress testing within 72 hours, provided serial troponins are negative and ECG shows no dynamic changes.
Q2: A trauma patient has BP 70/40, HR 140, distended abdomen, and positive FAST. What is the immediate next step?
A: Massive transfusion protocol activation (1:1:1 ratio of PRBC:FFP:platelets) and emergent exploratory laparotomy. This is hemorrhagic shock — needs immediate source control in the OR. Permissive hypotension (target SBP 80-90) until hemorrhage controlled.
Q3: What is the first-line treatment for anaphylaxis?
A: IM epinephrine 0.3-0.5 mg (1:1000 concentration) in the anterolateral thigh. Repeat q5-15 minutes if needed. Never give IV epinephrine except in cardiac arrest or severe refractory anaphylaxis under continuous monitoring.
Q4: According to the Ottawa Ankle Rules, which patients need ankle X-rays?
A: Patients with bone tenderness at the posterior edge of the distal 6 cm of the tibia or fibula, or inability to bear weight (4 steps) both immediately and in the ED. Misses only ~1-3% of fractures, reducing unnecessary X-rays by 30-40%.
Q5: What are the 5 H's and 6 T's of cardiac arrest reversible causes?
A: H's: Hypovolemia, Hypoxia, H+ (acidosis), Hypo/Hyperkalemia, Hypothermia. T's: Tension pneumothorax, Tamponade (cardiac), Toxins, Thrombosis (pulmonary embolism), Thrombosis (coronary), Trauma.

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