CEN Environment, Toxicology & Infection Practice Questions
Environment, Toxicology & Infection makes up 4 of every 50 questions on a Tigertest CEN practice test. Here are 10 of the 16 questions on it, each with the answer and the reason.
Updated by the Tigertest team. Based on the BCEN CEN Examination Content Outline effective July 2026. Original questions; 50 per test, weighted like the real exam. Not affiliated with BCEN.
1. By the adult rule of nines, what percent of body surface is the entire front of the trunk?
- A.36%
- B.18%
- C.9%
- D.27%
Answer: B. The anterior trunk is 18% and the posterior trunk another 18%. Each whole arm is 9% and each whole leg 18%.
2. An 80 kg adult has partial and full thickness burns over 50% of the body. Using the Parkland formula, how much fluid is given in the first 8 hours?
- A.16,000 mL
- B.2,000 mL
- C.4,000 mL
- D.8,000 mL
Answer: D. Parkland is 4 mL x kg x % burn = 4 x 80 x 50 = 16,000 mL over 24 hours. Half is given in the first 8 hours from the time of the burn.
3. A patient has full thickness burns that circle the chest and is having trouble ventilating. What procedure may be needed?
- A.Escharotomy
- B.Thoracentesis
- C.Fasciotomy of the leg
- D.Skin grafting at once
Answer: A. Stiff circumferential eschar can restrict chest movement. Cutting through it lets the chest expand.
4. A patient struck by lightning has a red, branching, fern-like pattern on the skin. What is this?
- A.Deep electrical burn
- B.A drug reaction
- C.Lichtenberg figures
- D.Contact dermatitis
Answer: C. Lichtenberg figures are a feathery pattern seen after lightning strikes. They are not true burns and fade within a day or two.
5. A worker had a high-voltage electrical injury with small skin burns. Why is the patient monitored closely?
- A.Risk of an allergy
- B.To check the vision
- C.Hidden deep tissue damage
- D.Small burns heal fast
Answer: C. Current runs along deep tissue, so small skin wounds can hide muscle damage, rhabdomyolysis and arrhythmias.
6. A hiker is confused and hot with a temperature of 41 C and hot dry skin. What is the priority?
- A.Rapid cooling
- B.Warm blankets
- C.Antipyretics only
- D.Oral fluids and rest
Answer: A. Heat stroke is a core temperature over 40 C with altered mental status. Rapid cooling, such as cold-water immersion, is the key treatment.
7. How is frostbitten tissue rewarmed in the emergency department?
- A.Hot water near 50 C
- B.Rubbing with snow
- C.Dry heat from a heater
- D.Warm water at 37 to 39 C
Answer: D. Rapid rewarming in circulating water at about 37 to 39 C gives the best outcome. Rubbing and dry heat damage the tissue. Rewarming is painful, so analgesia is given.
8. A patient was bitten by a dog on the hand. What is generally recommended?
- A.Let it bleed only
- B.Irrigate, give antibiotics
- C.Close it tightly at once
- D.Soak it in hot water
Answer: B. Hand bites carry a high infection risk. Thorough irrigation and often prophylactic antibiotics are used, and rabies risk is assessed.
9. A patient woke with a bat in the bedroom but no visible bite. What is advised?
- A.An antibiotic course
- B.Rabies prophylaxis
- C.No treatment needed
- D.A tetanus shot only
Answer: B. Bat bites can be tiny. When a sleeping person may have been exposed and the bat cannot be tested, rabies prophylaxis is recommended.
10. A family has headaches and nausea that improve when they leave home in winter. The pulse oximeter reads 99%. What is most likely?
- A.Food poisoning
- B.Seasonal allergies
- C.Seasonal influenza
- D.Carbon monoxide poisoning
Answer: D. CO binds hemoglobin, and standard pulse oximeters cannot tell it from oxygen. A co-oximetry level confirms it; 100% oxygen is given.
Practice all 16 environment, toxicology & infection questions, and the rest of the 200-question bank, in the free CEN training sets. Questions you miss come back until you have mastered them.
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