Optimal Duration of Therapy for Uncomplicated Brucellosis
For this patient with uncomplicated brucellosis, the optimal treatment duration is 6 weeks (Answer B). 1, 2, 3
Clinical Presentation Confirms Uncomplicated Brucellosis
This 28-year-old woman presents with classic features of acute brucellosis:
- Epidemiologic exposure: Raw milk ingestion is the key risk factor 3, 4
- Typical symptoms: Fever (38.5°C), generalized fatigability, malaise, arthralgia, and back pain over 3 weeks 3, 4
- Physical findings: Mild hepatosplenomegaly is common (occurs in 31-55% of cases) 4
- Laboratory abnormalities: Anemia (Hb 10.5 g/L) and thrombocytopenia (120 × 10⁹/L) are frequently seen in brucellosis 4, 5, 6
- Microbiologic confirmation: Gram-negative coccobacilli in blood culture is diagnostic for Brucella species 3, 7
Standard Treatment Duration: 6 Weeks
The World Health Organization, American College of Physicians, and Centers for Disease Control and Prevention all recommend 6 weeks as the standard treatment duration for uncomplicated brucellosis. 1, 2, 3
First-Line Regimen Options (All 6 Weeks Total Duration):
- Doxycycline 100 mg twice daily for 6 weeks PLUS streptomycin 15 mg/kg IM daily for 2-3 weeks (lowest relapse rate, gold standard) 1, 2, 3
- Doxycycline 100 mg twice daily for 6 weeks PLUS gentamicin 5 mg/kg IV daily for 7 days (WHO-recommended, comparable efficacy with wider availability) 1, 2, 3
- Doxycycline 100 mg twice daily for 6 weeks PLUS rifampicin 600-900 mg daily for 6 weeks (alternative when aminoglycosides contraindicated, but higher relapse rates) 1, 2, 3
Why Not Other Durations?
3 Weeks (Answer A) - Too Short
Shorter durations of 3 weeks are inadequate and associated with unacceptably high relapse rates. 2 Studies demonstrate that relapses are directly related to shorter duration of chemotherapy. 4
12 Weeks (Answer C) - Reserved for Complicated Disease
Treatment duration of 12 weeks is reserved for complicated brucellosis with focal involvement. 2 This extended duration is indicated when:
- Brucellar spondylitis is confirmed by MRI (the patient's back pain warrants careful evaluation, but there's no evidence of spinal involvement yet) 2, 3
- Neurobrucellosis is present 2
- Other focal complications develop 2
24 Weeks (Answer D) - Excessive for Any Indication
There is no indication for 24 weeks of treatment in brucellosis, even for complicated cases. 2 This duration is not supported by any guideline or evidence.
Critical Caveat: Evaluate for Spinal Involvement
The American College of Physicians specifically recommends careful attention to back pain in brucellosis patients, as it may represent brucellar spondylitis requiring extended treatment. 2
- If this patient's back pain persists or worsens, obtain MRI of the spine (97% sensitivity, 93% specificity) 3
- If MRI demonstrates spinal involvement, extend treatment to 12 weeks with aminoglycoside-containing regimens 2, 3
- Immobilize the spine if cervical involvement is present to prevent devastating neurological complications 3
Expected Outcomes with 6-Week Treatment
- Relapse rates: 5-15% even with appropriate 6-week treatment 1, 2, 3
- Fever resolution: Typically within 3-4 days of starting antibiotics 4
- Hepatosplenomegaly resolution: Slower response over weeks 4
- Relapses are usually mild and respond to the same regimens 1, 2, 3
Answer: B. 6 weeks