What is the next step in managing a 19-year-old man with bipolar disorder, taking lithium carbonate (lithium), bupropion (bupropion), and valproic acid (valproic acid), who presents with frequent nosebleeds and an elevated lithium level?

Management of Frequent Nosebleeds in a Patient with Bipolar Disorder on Psychotropic Medications

The most appropriate next step in management is to obtain a platelet count (option C) due to the patient's use of valproic acid, which can cause thrombocytopenia and lead to bleeding complications like epistaxis.

Analysis of the Clinical Scenario

This 19-year-old man presents with:

• Frequent nosebleeds over 3 weeks
• Bipolar disorder treated with:
  • Lithium carbonate (slightly above therapeutic range at 1.3 mEq/L)
  • Valproic acid (within therapeutic range at 77 μg/mL)
  • Bupropion
• Physical exam showing dried blood in nares
• Anxious mood and slight motor restlessness

Medication-Related Considerations

Valproic Acid and Bleeding Risk

• Valproic acid is known to cause thrombocytopenia, which can manifest as mucosal bleeding, particularly epistaxis 1
• Even with therapeutic serum levels (40-100 μg/mL), valproic acid can still cause platelet dysfunction or reduced platelet count
• Epistaxis (nosebleeds) is a common presentation of medication-induced bleeding disorders

Lithium Considerations

• The patient's lithium level is slightly elevated at 1.3 mEq/L (therapeutic range 0.6-1.2 mEq/L)
• While this elevation warrants monitoring, lithium is not typically associated with bleeding disorders
• Discontinuation of lithium without proper assessment could destabilize the patient's bipolar disorder

Bupropion Considerations

• Bupropion is not commonly associated with bleeding disorders
• Serum bupropion levels are not routinely monitored in clinical practice
• Measuring bupropion levels would not provide useful information for managing the nosebleeds

Diagnostic Approach

The clinical practice guideline for epistaxis management recommends documenting factors that increase bleeding frequency or severity, including medications that impair coagulation and platelet function 1. For this patient:

1. Platelet count (Option C) is the most appropriate next step because:

   • It directly assesses for valproic acid-induced thrombocytopenia
   • It provides actionable information that could guide medication adjustments
   • It is non-invasive and readily available

2. Other options are less appropriate:

   • AST measurement (Option A) would assess liver function but not directly address the bleeding issue
   • Serum bupropion level (Option B) is not clinically indicated as bupropion is not associated with bleeding
   • Discontinuation of lithium (Option D) is premature without first determining the cause of bleeding
   • Discontinuation of valproic acid (Option E) is premature without confirming thrombocytopenia

Management Algorithm

1. Obtain platelet count to assess for thrombocytopenia

2. If platelet count is low:

   • Consider dose reduction or discontinuation of valproic acid
   • Consult with psychiatrist for medication adjustment
   • Consider alternative mood stabilizers

3. If platelet count is normal:

   • Perform nasal endoscopy to identify bleeding site
   • Consider other causes of epistaxis (trauma, dryness, etc.)
   • Implement appropriate epistaxis management per guidelines 1

4. For immediate management of nosebleeds:

   • Apply direct pressure by pinching the soft part of the nose for at least 5 minutes
   • Use topical vasoconstrictors if available
   • Consider nasal moisturizing agents to prevent recurrence

Pitfalls to Avoid

• Don't discontinue psychotropic medications without first confirming the cause of bleeding, as this could destabilize the patient's psychiatric condition
• Don't overlook the slightly elevated lithium level, which should be addressed after the bleeding issue is evaluated
• Don't assume the nosebleeds are unrelated to medications, as valproic acid is a known cause of bleeding disorders
• Don't delay platelet count assessment, as continued bleeding could lead to significant morbidity

By obtaining a platelet count first, you can determine if valproic acid-induced thrombocytopenia is the cause of the nosebleeds before making any medication changes that could affect the patient's psychiatric stability.