A 32-year-old lactating mother develops sudden onset of severe breast pain, localized erythema, induration, and fever (38.5°C) on day 10 postpartum. Milk culture is pending. What is the drug of choice for empirical treatment of acute mastitis in a breastfeeding woman?

Explanation

## Empirical Antibiotic Therapy for Acute Mastitis ### Clinical Presentation Acute mastitis presents with: - Localized breast pain, erythema, induration - Systemic symptoms (fever, malaise) - Usually unilateral - Occurs 1–4 weeks postpartum (peak: days 7–14) ### Microbiology | Organism | Frequency | Notes | |----------|-----------|-------| | *Staphylococcus aureus* | 40–50% | Most common; includes MSSA and MRSA | | *Streptococcus agalactiae* (GBS) | 10–15% | Vertical transmission from vaginal flora | | *Escherichia coli* | 10% | From skin or fecal contamination | | *Streptococcus pyogenes* | 5% | Less common; associated with severe disease | ### First-Line Empirical Antibiotic **Key Point:** Flucloxacillin or cephalexin are the drugs of choice for empirical treatment of acute mastitis in lactating women. **High-Yield:** Why flucloxacillin/cephalexin? 1. **Spectrum:** Cover *S. aureus* (MSSA), *Streptococcus* species, and gram-positive cocci 2. **Lactation safety:** Minimal excretion into breast milk; safe to continue breastfeeding 3. **Tissue penetration:** Excellent breast tissue penetration 4. **Dosing:** Flucloxacillin 500 mg 6-hourly or Cephalexin 500 mg 6-hourly for 10–14 days 5. **Guideline-recommended:** WHO, RCOG, and Indian pediatric guidelines endorse these agents ### Clinical Pearl **Continue breastfeeding during treatment.** Continued milk removal is essential for: - Preventing breast abscess formation - Improving antibiotic delivery to infected tissue - Reducing duration of symptoms - Maintaining milk supply ### Management Algorithm ```mermaid flowchart TD A[Acute mastitis diagnosed]:::outcome --> B[Start empirical antibiotic]:::action B --> C[Flucloxacillin or Cephalexin]:::action C --> D[Continue frequent breastfeeding]:::action D --> E[Milk culture result]:::outcome E -->|MSSA/GBS/Strep| F[Continue same antibiotic]:::action E -->|MRSA| G[Switch to Clindamycin or Trimethoprim-sulfamethoxazole]:::action E -->|Gram-negative| H[Consider adding coverage]:::action I[Fever resolves in 48-72 hrs] -->|Yes| J[Complete 10-14 days]:::action I -->|No/Worsening| K[Reassess for abscess]:::decision ``` ### Duration - Minimum 10–14 days of antibiotics - Most cases resolve within 48–72 hours of starting appropriate therapy - Failure to improve suggests abscess formation or resistant organism [cite:Park 26e Ch 8; WHO Guidelines on Infant Feeding]