What is the treatment for bubonic plague?

Treatment of Bubonic Plague

For bubonic plague, streptomycin (15 mg/kg intramuscularly every 12 hours) or doxycycline (100 mg twice daily orally) is recommended as first-line treatment, with gentamicin as an acceptable alternative to streptomycin. 1

First-Line Treatment Options

Adults

• Aminoglycosides:

  • Streptomycin: 1 g every 12 hours IM (may be given IV)
  • Gentamicin: 5 mg/kg every 24 hours IV or IM

• Tetracyclines:

  • Doxycycline: 100 mg twice daily orally or IV (200 mg loading dose)

• Fluoroquinolones:

  • Ciprofloxacin: 400 mg IV every 8 hours or 750 mg orally every 12 hours
  • Levofloxacin: 750 mg every 24 hours IV or orally
  • Moxifloxacin: 400 mg every 24 hours IV or orally

Children

• Aminoglycosides:

  • Streptomycin: 15 mg/kg every 12 hours IM (maximum 1 g/dose)
  • Gentamicin: 4.5-7.5 mg/kg every 24 hours IV or IM

• Tetracyclines:

  • Doxycycline: For children <45 kg: 4.4 mg/kg loading dose, then 2.2 mg/kg every 12 hours
    • For children ≥45 kg: adult dosing

• Fluoroquinolones:

  • Ciprofloxacin: 10 mg/kg every 8-12 hours IV or 15 mg/kg every 8-12 hours orally
  • Levofloxacin: For children <50 kg: 8 mg/kg every 12 hours (maximum 250 mg/dose)
    • For children ≥50 kg: adult dosing

Treatment Duration and Monitoring

Treatment should be continued for 10-14 days 1. For naturally acquired bubonic plague, monotherapy with one of the above agents is sufficient, but for severe cases or suspected bioterrorism, dual therapy with two distinct antimicrobial classes is recommended 1.

Clinical Presentation and Diagnosis

Bubonic plague presents with:

• Sudden onset of fever, headache, and chills
• Tender regional lymphadenopathy (buboes) developing 2-6 days after exposure
• Possible skin lesion at the portal of entry
• Risk of progression to septicemic or secondary pneumonic plague if untreated

Diagnosis should be made by:

• Gram stain and culture of aspirated material from suppurative lymph nodes
• Blood cultures (may be positive in septicemic spread)
• PCR testing at reference laboratories
• Serologic tests for retrospective confirmation

Special Considerations

1. Isolation precautions: Standard precautions are sufficient for bubonic plague. However, if pneumonic symptoms develop, implement droplet precautions until 48 hours of effective antibiotic therapy and clinical improvement 1.

2. Plague meningitis: If meningeal signs develop, consider dual therapy with chloramphenicol plus moxifloxacin or levofloxacin 1.

3. Pregnancy: Gentamicin is generally preferred over doxycycline or fluoroquinolones due to potential fetal effects of the latter.

4. Treatment efficacy: A randomized clinical trial in Tanzania demonstrated comparable efficacy between gentamicin and doxycycline, with favorable response rates of 94% and 97%, respectively 2.

5. Mortality risk: Early diagnosis and prompt initiation of treatment reduce mortality rates for bubonic plague to 5-50%, but delays beyond 24 hours can be fatal 3. Historical data shows mortality of only 9% with high-efficacy antimicrobials versus 51% with limited-efficacy options 4.

Common Pitfalls to Avoid

1. Delayed treatment: Do not wait for laboratory confirmation before initiating therapy if plague is suspected.

2. Inadequate antibiotic choice: Avoid antibiotics not listed as first-line or alternative options, as mortality is significantly higher with ineffective agents.

3. Failure to monitor for complications: Watch for development of secondary pneumonic plague, which requires additional isolation precautions.

4. Inadequate duration: Complete the full 10-14 day course of antibiotics even if clinical improvement occurs rapidly.

5. Missing septicemic progression: Monitor for signs of sepsis and adjust therapy accordingly if the patient deteriorates.

Bubonic plague remains a rare but serious condition with excellent outcomes when recognized and treated promptly with appropriate antibiotics.