CEN Medical Emergencies Study Guide and Practice Questions
Review anaphylaxis, sepsis, shock, metabolic emergencies, blood disorders, and substance-related illness. Focus on the finding that makes a condition urgent. This free CEN medical emergencies study guide follows the current BCEN outline and includes two short practice questions. [1]
What BCEN expects in Medical Emergencies
BCEN combines allergic, hematologic, fluid/electrolyte, endocrine, immunocompromised, sepsis, hypovolemic/distributive shock, substance use, and withdrawal presentations in this domain. Use physiology to connect them. [1]
This free guide covers high-yield review. The paid course contains substantially more. Get the full Medical Emergencies lesson path, detailed explanations, clinical decisions, case labs, and CEN-style practice with complete answer rationales. See what is included in the course.
Anaphylaxis and allergic reactions
Separate skin-only symptoms from airway, respiratory, or circulatory compromise and give the right first-line treatment.
Sepsis and immunocompromise
Recognize organ dysfunction, treat infection promptly, and never rely on fever alone in an immunocompromised patient.
Hypovolemic and distributive shock
Assess source, volume status, tissue perfusion, and response to fluids or vasopressors under protocol.
Endocrine and fluid/electrolyte disorders
Distinguish DKA/HHS, hypo- and hyperglycemia, sodium abnormalities, and potassium-related dysrhythmia risk.
Hematologic disorders
Identify sickle-cell complications, severe anemia/bleeding, thrombosis risk, and other high-risk blood presentations.
Substance use and withdrawal
Address overdose physiology and life-threatening alcohol or sedative withdrawal, with attention to breathing and seizures.
Make It Stick: When a stem offers a long diagnosis list, the vital signs often tell you what to do first.
Six medical emergency patterns to review
Focus on recognition, key differences, and initial priorities. Detailed interpretation, management sequences, and case reasoning are developed in the paid lessons.
1. Anaphylaxis: recognize airway and circulatory involvement
New hoarseness, wheeze, throat or tongue swelling, hypotension, or multisystem symptoms after an exposure can indicate anaphylaxis. Skin findings may be absent. Prompt intramuscular epinephrine is the first-line medication under protocol, alongside airway and circulatory support. [3] [4] [5]
Exam trap: Antihistamines do not replace epinephrine for airway or circulatory compromise. Reassess breathing, pressure, and recurrence rather than assuming initial symptom relief ends the emergency.
2. Sepsis and immunocompromise
Suspected infection with altered mentation, hypotension, respiratory deterioration, or poor perfusion raises concern for sepsis. Prompt evaluation, treatment, and repeated assessment of organ function matter. Immunocompromised patients may not mount a prominent fever despite serious infection. [3] [4] [6]
CEN Thinking: A normal temperature cannot clear a patient with a concerning trajectory. Recognize changes from baseline and escalate possible organ dysfunction without waiting for every classic finding.
3. Hypovolemic and distributive shock
Hypovolemic shock involves inadequate circulating volume from blood or fluid loss. Distributive shock includes conditions such as sepsis and anaphylaxis that require treatment of the cause as well as circulatory support. Track mentation, skin, pulse, pressure, urine output, and response. [3] [4]
Key distinction: An initially normal blood pressure does not guarantee adequate perfusion. Improvement should be reflected in the patient, and treatment needs reassessment rather than repetition by habit.
4. Glucose crises and endocrine disorders
Altered mental status warrants prompt glucose assessment. Review severe hypoglycemia, DKA, and HHS with attention to hydration, cognition, acid-base disturbance, and potassium. Insulin can lower potassium as well as glucose, so an insulin decision requires the full clinical picture. [3] [4]
Also review adrenal and thyroid emergencies through temperature, mental status, perfusion, and medication history. Exam trap: A striking glucose value does not mean every other abnormality can wait.
5. Fluid, electrolyte, and hematologic emergencies
Potassium disturbances can cause weakness and dangerous dysrhythmias; an abnormal ECG with a critical potassium result increases urgency. Sodium disorders require interpretation in context, including onset and neurological symptoms. Avoid treating a laboratory value without assessing its clinical effects. [3] [4]
Hematologic illness may involve symptomatic anemia, bleeding, infection, or acute sickle-cell complications. Do not miss: A chronic diagnosis does not make new hypoxemia, fever, chest symptoms, or poor perfusion routine.
6. Substance use, overdose, and withdrawal
In suspected opioid toxicity, inadequate breathing makes ventilatory support an immediate priority; naloxone is used as indicated with ongoing reassessment. Apparent recovery may be followed by recurrence. Look for co-ingestion, injury, and other medical causes. [3] [4]
Alcohol or sedative withdrawal can progress from tremor and agitation to seizures or severe instability. CEN Thinking: Evaluate the direction of change, not just the substance history or the patient’s initial behavior.
Three distinctions worth remembering
| Clue | What it changes |
|---|---|
| Exposure + airway or circulatory compromise | Recognize possible anaphylaxis even without a rash. |
| Infection + altered mentation or poor perfusion | Escalate possible organ dysfunction. |
| High glucose + low potassium | Consider both abnormalities before treatment decisions. |
On a phone, swipe sideways if needed. Use these reminders with the context and sources in the review above.
Before you move on: Can you identify airway compromise, poor perfusion, a dangerous electrolyte pattern, and ventilatory failure? Match the concern to the whole patient before focusing on one laboratory value.
Review exam format in the CEN Exam Guide, or use the main free CEN exam study guide to move between domains.
Two CEN medical emergencies practice questions
These original review questions check selected distinctions. They are not BCEN exam items or a readiness score.
Minutes after IV antibiotic administration, a patient becomes hoarse and wheezy with BP 78/42 mm Hg. Which medication should be administered first per protocol?
- A.Diphenhydramine
- B.Intramuscular epinephrine
- C.An oral corticosteroid
- D.Acetaminophen
A patient with DKA has glucose 480 mg/dL and serum potassium 2.8 mmol/L. An insulin infusion is ordered. Which action should the nurse prioritize before starting insulin?
- A.Begin insulin immediately because glucose is high
- B.Give bicarbonate as the only treatment
- C.Notify the clinician and begin ordered potassium replacement with monitoring
- D.Delay all fluids until potassium normalizes
Get the full Medical Emergencies learning experience.
The paid version goes far beyond this free review. This page shows you what to revisit. The full Nurscience course teaches why the findings matter, how to choose the next action, and how to apply that reasoning to CEN-style questions.
- Structured medical emergency lessons
- Diagnostic and laboratory interpretation in context
- Treatment decisions for shock and metabolic emergencies
- Case labs linking clinical patterns with the next action
- Lesson quizzes and focused domain practice
- Complete rationales explaining correct and incorrect answers
Across all 11 domains, the full CEN prep course includes 1,600 practice questions, domain practice, and full-length exam preparation. It includes approximately 20 hours of written lesson material, or about 30 hours including completing each lesson quiz once. These are study-time estimates; your pace may vary.
Sources and review notes
Updated September 26, 2026. The BCEN outline effective July 2026 defines exam scope; emergency-nursing texts and authoritative clinical guidance inform the teaching points. This is an independent study resource, not an official BCEN publication or a replacement for local protocols.
- BCEN. CEN Examination Content Outline, effective July 2026.
- BCEN. CEN Certification Exam Resource List (2026).
- Emergency Nurses Association. Emergency Nursing Core Curriculum, 8th ed. Elsevier; 2027. Chapters 11, 13, 16, 17, 18, and 24.
- Emergency Nurses Association. Sheehy’s Manual of Emergency Care, 8th ed. Elsevier; 2024. Chapters 15, 32, 33, and 35.
- AAAAI/ACAAI Joint Task Force. Anaphylaxis: A 2023 Practice Parameter Update.
- Society of Critical Care Medicine / European Society of Intensive Care Medicine. Surviving Sepsis Campaign: International Guidelines for Management of Sepsis and Septic Shock (2026).