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Mastitis

DESCRIPTION

  • Inflammation of breast parenchyma Β± areola, nipple, SC fat
  • Acute or chronic (chronic cystic mastitis)
  • Lactational or nonlactational

EPIDEMIOLOGY

  • Primarily affects females, mostly during puerperium
  • 3–20% of breastfeeding mothers affected, peak at 2–6 weeks postpartum
  • Neonatal: 1–5 weeks, equal gender risk, unilateral
  • Pediatric: around puberty, 82% female

ETIOLOGY & PATHOPHYSIOLOGY

Infectious Causes

Puerperal: S. aureus (incl. MRSA), Strep. pyogenes, E. coli, Corynebacterium, etc.
Nonpuerperal: S. aureus, Bacteroides, Histoplasma, Actinomyces, Salmonella, etc.
TB mastitis: 1% in endemic areas; also in immunosuppressed (TNF-Ξ± inhibitors)

Granulomatous Mastitis

  • Idiopathic: common in Asian & Hispanic women
  • Associated with Ξ±1-antitrypsin deficiency, galactorrhea, OCPs, trauma
  • Reported in MTF transgender patients (on progesterone/estrogen)

Mechanisms

  • Retrograde infection via nipple fissures
  • Plugged ducts, milk stasis, lymphatic spread
  • Secondary infections: monilial (esp. recurrent or in diabetics)

RISK FACTORS

  • Milk stasis: interrupted feeds, poor latch, oversupply
  • Nipple trauma (e.g. piercing, pump injury)
  • Breast surgery scars, prior mastitis
  • Smoking, maternal diabetes or HIV
  • Neonatal colonization (esp. bottle-fed)

PREVENTION

  • Regular breast emptying, nipple care
  • Good hygiene (e.g. pump cleaning)

ASSOCIATED CONDITIONS

- Breast abscess

CLINICAL FEATURES

Symptoms

  • Fever >38.5Β°C, malaise, myalgia, nausea Β± vomiting
  • Breast pain, "hot cords" in chest

Signs

  • Tenderness, redness, swelling, warmth, firmness
  • Peau d'orange skin

DIFFERENTIAL DIAGNOSIS

  • Abscess, IGM, inflammatory breast CA
  • Sarcoidosis, Wegener's, ductal ectasia
  • Mondor disease (thrombophlebitis)
  • Vasospasm (Raynaud's), fungal (Candida)

INVESTIGATIONS

  • Mostly clinical diagnosis
  • Labs: CBC, blood cultures (if severe)
  • Milk culture (esp. recurrent or suspect MRSA)
  • US: assess for abscess or implant
  • Mammogram: nonlactational mastitis, age >40
  • Biopsy: IGM or persistent mass

TREATMENT

Conservative (mild cases <24h)

  • Milk removal, warm compress, analgesia

Antibiotics (10–14 days)

Outpatient: - Dicloxacillin or Cephalexin 500 mg QID - TMP-SMX DS BID (MRSA) - Doxycycline 100 mg BID (≀3 weeks) - Probiotics: Lactobacillus fermentum/salivarius Inpatient: - Nafcillin, Oxacillin, Vancomycin, Daptomycin Adjuncts: - Metronidazole if odoriferous/anaerobic - Nystatin for yeast (topical/oral)

Granulomatous Mastitis

  • Mild: observation
  • Moderate: antibiotics, corticosteroids Β± methotrexate or mycophenolate
  • Severe/persistent: surgery (with/without steroids)

COMPLEMENTARY THERAPIES

  • Cabbage leaf compress (limit: 15 min BID)
  • Sunflower lecithin 1200 mg TID–QID (plugs)
  • Lymphatic drainage massage

ADMISSION INDICATIONS

  • Failed outpatient care
  • Severe infection
  • Neonatal mastitis In-hospital care:
  • Breastfeeding/pumping encouraged
  • Infant rooming-in preferred
  • Frequent milk removal
  • Start feeds on affected side

FOLLOW-UP

  • Monitor symptom resolution
  • Repeat imaging if persistent or recurrent
  • Mammogram/US if >40 yrs or red flag signs

PATIENT EDUCATION

  • Safe to continue breastfeeding
  • Emphasize good latch and nipple care
  • Encourage hydration, vitamins (esp. A)

PROGNOSIS

  • 96% recover with prompt antibiotics + drainage
  • 11% develop abscess if untreated
  • IGM has high recurrence; close follow-up advised

COMPLICATIONS

- Abscess, recurrence, bacteremia, sepsis

ICD-10 CODES

  • O91.11 – Abscess with pregnancy
  • O91.211 – Nonpurulent mastitis (1st trimester)
  • O91.113 – Abscess (3rd trimester)

CLINICAL PEARLS

  • Feed/pump regularly (q3–4h), avoid tight bras
  • Recurrence in same location = imaging + biopsy
  • Abscess is NOT a contraindication to breastfeeding
  • Poor response to therapy β†’ consider: abscess, resistant bug, IGM, malignancy