In an 18‑year‑old woman with painless bilateral eyelid swelling after a recent viral upper‑respiratory infection, who is taking pseudoephedrine (Sudafed) and has a resting tachycardia, what is the appropriate initial management?

Immediate Management: Discontinue Pseudoephedrine and Evaluate for Infectious Mononucleosis

The most critical immediate step is to discontinue Sudafed (pseudoephedrine) given the resting tachycardia of 120 bpm, and evaluate for infectious mononucleosis (IM) as the cause of bilateral eyelid swelling following recent viral illness.

Discontinue Pseudoephedrine Immediately

• Pseudoephedrine is directly causing the tachycardia and should be stopped immediately, as meta-analysis demonstrates it increases heart rate by 2.83 beats/min on average, with individual variation causing more pronounced effects in some patients 1, 2.
• The cardiovascular effects include elevated blood pressure and palpitations, with potential for serious arrhythmias, particularly when combined with other stimulants or in susceptible individuals 1.
• At a resting heart rate of 120 bpm, this patient is experiencing significant sympathomimetic effects that warrant immediate cessation 1.

Evaluate for Infectious Mononucleosis (EBV)

• Bilateral painless periorbital edema following a recent viral illness with fever, sore throat, and cough is highly suggestive of infectious mononucleosis caused by Epstein-Barr virus 3.
• Periorbital edema can present early in IM, even before or alongside the classic triad of fever, pharyngitis, and cervical lymphadenopathy 3.
• The edema can have a protracted course lasting significantly longer than typically described in literature 3.

Diagnostic Workup for IM

• Obtain heterophile antibody test (Monospot) or EBV-specific serology (VCA-IgM, VCA-IgG, EBNA) 3.
• Complete blood count with differential to assess for atypical lymphocytosis 3.
• Liver function tests, as hepatic involvement is common 3.

Alternative Symptomatic Management

Since the recent viral illness has resolved but residual symptoms may persist:

• Nasal saline irrigation provides symptomatic relief with low risk of adverse effects for any residual nasal congestion 4, 5, 4.
• Intranasal corticosteroids may provide symptomatic relief if nasal symptoms persist, with low burden of risk 5.
• Topical oxymetazoline (if nasal congestion is severe) may be used for 3-5 days maximum to avoid rhinitis medicamentosa, but counsel about rebound congestion 5.
• Avoid oral decongestants entirely given the cardiovascular response already demonstrated 1.

Monitor and Reassess

• Recheck heart rate after discontinuing pseudoephedrine; it should normalize within hours to days as the drug is eliminated (half-life approximately 5-8 hours) 1.
• Monitor the periorbital edema; if due to IM, it should gradually resolve over days to weeks, though duration can be variable 3.
• If tachycardia persists after pseudoephedrine discontinuation, consider alternative causes including thyroid dysfunction, primary cardiac arrhythmia, or other systemic conditions 1.

Red Flags Requiring Further Evaluation

• Persistent tachycardia after pseudoephedrine washout suggests alternative etiology requiring cardiac workup 1.
• Worsening periorbital swelling, pain, vision changes, or proptosis would necessitate imaging to exclude orbital cellulitis, dacryoadenitis, or other serious orbital pathology 6, 7.
• Development of severe systemic symptoms (high fever >39°C, severe headache, neck stiffness) requires urgent evaluation for complications 4.

Avoid Future Pseudoephedrine Use

• Counsel the patient to avoid all oral decongestants containing pseudoephedrine or phenylephrine given her demonstrated cardiovascular sensitivity 1.
• Note that phenylephrine is less effective than pseudoephedrine and has questionable efficacy as an oral decongestant per FDA advisory committee review 5.
• Provide written list of safe alternatives for future upper respiratory infections, emphasizing nasal saline and intranasal corticosteroids 4, 5, 4.