# A 42-year-old client arrives at the emergency department 20 minutes after receiving an IM ceftriaxone injection at a clinic. The client feels faint and has diffuse hives, swollen lips, and audible expiratory wheezing. The client has no history of asthma, takes no daily medications, and has never had lip swelling before. Vital signs: blood pressure 86/54 mm Hg, heart rate 118/min, respiratory rate 28/min, oxygen saturation 90% on room air. The client is anxious but alert, and the skin is flushed and warm. Complete the diagram by selecting the condition the client is most likely experiencing, 2 actions the nurse should take to address that condition, and 2 parameters the nurse should monitor to assess the client's progress.

> source: MyMerci (mymerci.kr)  
> url: https://mymerci.kr/pages/nclex_q.php?qn_id=617427&lang=en  
> language: en  
> subject: Medical Emergencies  
> category: PA

## Question

A 42-year-old client arrives at the emergency department 20 minutes after receiving an IM ceftriaxone injection at a clinic. The client feels faint and has diffuse hives, swollen lips, and audible expiratory wheezing. The client has no history of asthma, takes no daily medications, and has never had lip swelling before. Vital signs: blood pressure 86/54 mm Hg, heart rate 118/min, respiratory rate 28/min, oxygen saturation 90% on room air. The client is anxious but alert, and the skin is flushed and warm. Complete the diagram by selecting the condition the client is most likely experiencing, 2 actions the nurse should take to address that condition, and 2 parameters the nurse should monitor to assess the client's progress.

Condition

Select 1
Severe acute asthma exacerbation
Anaphylaxis
Vasovagal reaction after injection
ACE inhibitor–induced angioedema

Actions to take

Select 2
Give prescribed IV diphenhydramine 50 mg
Give prescribed nebulized albuterol first
Give IM epinephrine 0.5 mg in the thigh
Infuse a rapid bolus of isotonic IV fluid
Give prescribed IV methylprednisolone

Parameters to monitor

Select 2
Blood pressure
Serum tryptase level
Capillary blood glucose
Oxygen saturation
Serum eosinophil count

## Explanation

Skin and mucosal involvement with respiratory compromise and hypotension within minutes of antibiotic exposure meets the criteria for anaphylaxis. IM epinephrine in the thigh is first-line, and a rapid isotonic fluid bolus treats distributive hypotension. Antihistamines, steroids, and albuterol are adjuncts that do not reverse shock; blood pressure and oxygen saturation show the response.

## In-depth explanation

Quick answer
Anaphylaxis. Give IM epinephrine 0.5 mg in the thigh and infuse a rapid isotonic fluid bolus. Monitor blood pressure and oxygen saturation.

Why this is correct
Hives, lip swelling, wheezing, and a blood pressure of 86/54 within 20 minutes of an injected antibiotic involve the skin, airway, and circulation. Asthma would not explain hives and hypotension. A vasovagal reaction causes bradycardia and pallor, not a heart rate of 118 with flushed skin. ACE inhibitor angioedema causes swelling without hives or shock, and this client takes no medications. Epinephrine reverses vasodilation, airway swelling, and bronchospasm, and fluids restore the volume lost to leaky vessels. Blood pressure and saturation show whether shock and hypoxemia are resolving.

Easy analogy or mental picture
Anaphylaxis is every faucet in the house opening at once: epinephrine turns the main valve, and fluids refill the tank; antihistamines only tighten one faucet.

Memory hook
Hives + low BP after a trigger = epi in the thigh, then fluids.

NCLEX decision rule
In anaphylaxis, IM epinephrine is given first and without delay. Adjunct drugs never come before it.

Why the other choices are wrong
Diphenhydramine and methylprednisolone are commonly given, but they are adjuncts that relieve hives or may reduce later symptoms and do not treat shock or airway swelling. Albuterol given first is the asthma approach; it can help wheezing only after epinephrine. Serum tryptase can support the diagnosis later but does not show the response to treatment. Glucose monitoring relates to steroid effects, and the eosinophil count reflects chronic allergic disease, not acute anaphylaxis.

References
1Resuscitation Council UK — Emergency Treatment of AnaphylaxisIM epinephrine first, IV fluids for shock, antihistamines and steroids as non-first-line
2MedlinePlus — AnaphylaxisSigns of anaphylaxis and emergency epinephrine treatment

## Clinical scenario

Scenario
Twenty minutes after IM ceftriaxone, a client without asthma or daily medications develops hives, lip swelling, wheezing, hypotension, tachycardia, and hypoxemia.

## Key concepts

- **Anaphylaxis** — A rapid, life-threatening systemic hypersensitivity reaction that involves the skin, airway, breathing, or circulation.
- **IM epinephrine** — First-line treatment for anaphylaxis, given into the anterolateral thigh (0.5 mg for adults, repeated every 5 minutes as needed).
- **Distributive shock** — Hypotension caused by widespread vasodilation and capillary leak, as in anaphylaxis.

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