What is the management for a patient who develops chills, fever, and lymphadenopathy after receiving a ketamine (anesthetic) injection?

Management of Chills, Fever, and Lymphadenopathy Following Ketamine Injection

For a patient experiencing chills, fever, and lymphadenopathy after ketamine injection, immediately stop the ketamine administration, provide supportive care with antipyretics and antihistamines, and monitor vital signs closely for at least 24 hours. 1

Initial Assessment and Management

Immediate Actions

• Stop ketamine administration immediately
• Assess airway, breathing, and circulation (ABC approach)
• Monitor vital signs (temperature, blood pressure, heart rate, respiratory rate, oxygen saturation)
• Establish IV access if not already present
• Administer oxygen if oxygen saturation is <95% 1

Differential Diagnosis

1. Infusion reaction to ketamine
2. Anaphylactic/anaphylactoid reaction
3. Malignant hyperthermia (rare but serious)
4. Infection/sepsis (if contaminated injection)

Treatment Algorithm

For Mild to Moderate Symptoms (Grade 1-2)

1. Antipyretics:

   • Acetaminophen 650-1000 mg orally or IV 1
   • NSAIDs if not contraindicated

2. Antihistamines:

   • Chlorphenamine 10 mg IV (adult dose) 1
   • Diphenhydramine 25-50 mg IV as an alternative

3. Hydration:

   • IV crystalloids (0.9% saline or lactated Ringer's) 1

4. Monitoring:

   • Vital signs every 4 hours
   • Temperature monitoring
   • Observe for progression of symptoms

For Severe Symptoms (Grade 3-4)

1. All measures for mild-moderate symptoms PLUS:

2. Corticosteroids:

   • Hydrocortisone 200 mg IV (adult dose) 1

3. For Hypotension:

   • IV fluid bolus (500-1000 mL)
   • If persistent hypotension: Epinephrine 50 μg IV (0.5 mL of 1:10,000 solution) 1, 2
   • Consider vasopressor infusion if needed

4. For Significant Bronchospasm:

   • Salbutamol (albuterol) nebulizer or metered-dose inhaler
   • Consider IV magnesium sulfate 1

5. Intensive Monitoring:

   • Continuous cardiac monitoring
   • Frequent vital sign checks (every 1-2 hours)
   • Consider arterial line placement for unstable patients

For Suspected Malignant Hyperthermia

If temperature >38.5°C with muscle rigidity, implement the following:

1. Dantrolene:

   • Initial dose: 2 mg/kg IV 1
   • Repeat until stabilization of symptoms

2. Aggressive Cooling:

   • Cold IV fluids (4°C)
   • Surface cooling with ice packs in axillae and groin 1

3. Supportive Care:

   • Treat acidosis with sodium bicarbonate if pH <7.2
   • Treat hyperkalemia if present 1

Laboratory Investigations

• Complete blood count with differential
• Basic metabolic panel
• Liver function tests
• Blood cultures (if infection suspected)
• Mast cell tryptase levels (to evaluate for anaphylaxis):
  • Initial sample as soon as feasible
  • Second sample at 1-2 hours after symptom onset
  • Third sample at 24 hours or in convalescence 1

Follow-up and Prevention

1. Monitoring Duration:

   • Monitor for a minimum of 24 hours in an appropriate setting (ICU, HDU, or recovery unit) 1

2. Documentation:

   • Document the reaction in detail
   • Add ketamine to patient's allergy list if reaction is confirmed

3. Future Anesthesia/Analgesia:

   • Avoid ketamine in future treatments
   • Consider referral to allergy specialist for further evaluation

Special Considerations

• Lymphadenopathy: This is an uncommon feature of simple ketamine reactions and may indicate an immune-mediated response. Document location and characteristics of lymph node enlargement.

• Persistent Symptoms: If symptoms persist beyond 24-48 hours, consider alternative diagnoses and broader infectious workup.

• Urological Symptoms: Monitor for urinary symptoms, as ketamine has been associated with urological complications in some patients 3.

By following this structured approach, clinicians can effectively manage the potentially serious complications of chills, fever, and lymphadenopathy following ketamine administration while minimizing morbidity and mortality risks.