A 32-year-old multiparous woman, 10 days postpartum, presents with right breast pain, erythema, and induration in the upper outer quadrant. Temperature is 38.8°C. She reports malaise and myalgias. Breastfeeding is extremely painful on the affected side. On examination, the right breast shows localized warmth, erythema, and a tender nodule. Milk expression yields normal-appearing milk. What is the most appropriate next step in management?

Explanation

## Diagnosis: Acute Mastitis This patient presents with **acute infectious mastitis**, characterized by: - Localized breast erythema, warmth, and induration - Fever (38.8°C) with systemic symptoms (malaise, myalgias) - Temporal relationship to lactation (10 days postpartum) - Unilateral presentation (upper outer quadrant — common site) ### Key Point: **Acute mastitis is a bacterial infection of breast tissue, typically caused by *Staphylococcus aureus* (including MRSA in some regions) or *Streptococcus agalactiae*.** It occurs in 1–3% of lactating women and requires prompt antibiotic therapy. ## Pathophysiology ```mermaid flowchart TD A[Milk stasis ± nipple trauma]:::outcome --> B[Bacterial colonization<br/>of lactiferous ducts]:::outcome B --> C[Localized inflammation]:::outcome C --> D{Untreated or<br/>delayed antibiotics?}:::decision D -->|No| E[Resolution with antibiotics]:::action D -->|Yes| F[Progression to abscess]:::urgent F --> G[Fluctuance, imaging confirmation]:::outcome G --> H[Needle aspiration or surgical drainage]:::action ``` ### High-Yield Management of Acute Mastitis | Feature | Management | |---------|-------------| | **First-line antibiotic** | Oral amoxicillin-clavulanate 625 mg TDS or cephalexin 500 mg QID (covers *S. aureus* and streptococci) | | **Duration** | 10–14 days | | **Breastfeeding** | **Continue** — milk removal aids resolution; antibiotics are safe | | **Analgesia** | Paracetamol or ibuprofen | | **Supportive care** | Frequent feeding, warm compresses before feeds, cold compresses between feeds | | **Follow-up** | Review at 48 hours; if no improvement, consider imaging and IV antibiotics | | **Imaging** | Ultrasound only if: (1) no response to antibiotics in 48 hrs, (2) clinical suspicion of abscess (fluctuance), or (3) recurrent mastitis | ### Clinical Pearl: **Continuing breastfeeding during mastitis is safe and therapeutic.** Milk removal reduces stasis and accelerates resolution. Antibiotics used for mastitis (beta-lactams, macrolides, fluoroquinolones) are compatible with lactation. ### High-Yield Fact: **Empiric oral antibiotics are first-line for uncomplicated acute mastitis.** IV antibiotics are reserved for: - Severe systemic toxicity or sepsis - Failure to improve within 48 hours on oral therapy - Immunocompromised patients ## Why NOT the Other Options **Option B (IV cephalosporin + admission):** Excessive for uncomplicated mastitis. IV therapy is indicated only if oral antibiotics fail within 48 hours or if the patient is systemically unwell (high fever, hypotension, altered mental status). This patient has localized disease with mild-to-moderate fever and is suitable for outpatient oral therapy. **Option C (Discontinue breastfeeding + bromocriptine):** Contraindicated. Stopping breastfeeding worsens milk stasis and delays resolution. Bromocriptine carries systemic risks and is not indicated for mastitis management. Continued milk removal is essential. **Option D (Topical antibiotics + reassurance):** Inadequate. Topical antibiotics do not achieve therapeutic concentrations in breast tissue. Systemic oral antibiotics are required. Spontaneous resolution without antibiotics risks progression to abscess formation (10–15% of untreated mastitis). ### Mnemonic: MASTITIS Management - **M**ilk removal (frequent feeding) - **A**ntibiotics (oral amoxicillin-clavulanate first-line) - **S**upport (analgesia, warm compresses) - **T**emperature monitoring (review at 48 hrs) - **I**maging (ultrasound only if no improvement) - **T**reatment duration (10–14 days) - **I**mmunocompromised? (consider IV therapy) - **S**afe for lactation (continue breastfeeding)