Management of Common Complications of Lactation – Mastitis

Myth:
- Mastitis represents a bacterial infection resulting from milk stasis, engorgement, and “plugging”
Science:
- When an infant sleeps through the night or mothers do not express their milk at work as regularly as the infant breastfeeds at home:
  - Patients experience transient engorgement and pain
- Women may also develop breast erythema and edema:
  - From congested capillaries and interstitial fluid (Figure):
    - Which can cause sweating, fever, and chills:
      - As it is an inflammatory process in a body organ with robust blood supply
    - This systemic inflammatory response syndrome may be mistaken for signs and symptoms of infection:
      - Raising alarm for impending development of bacterial mastitis
    - However, unless a person has developed a very rare rapidly progressive soft tissue infection:
      - It is otherwise very unusual for average bacterial mastitis to present this quickly
- Lactation literature commonly describes a theory that mastitis results from milk stasis:
  - Mothers are warned to avoid long stretches without breastfeeding or pumping to avoid build-up of stagnant milk and progression to “plugging” and infectious mastitis:
    - However, there is no scientific evidence to support the idea that mastitis results from milk stasis
    - In contrast to a passive repository such as a bladder, the breast is a gland with production regulated by Feedback Inhibitor of Lactation (FIL):
      - Therefore, continued removal of milk increases production and worsens tissue edema and inflammation:
        
        Reduced removal of milk will allow for FIL to downregulate production and enable resorption of milk not used
- Mastitis results from underlying microbiome disruption and ductal inflammation and is therefore often observed in patients with hyperlactation and/or blebs
  - Most cases of lactational mastitis are purely inflammatory and can be resolved with conservative measures and appropriate management of lactation
  - Breastmilk contains numerous immunologic cells and substances:
    - That counteract infection
  - In similar fashion, it is uncommon for stagnant milk contained in a galactocele to become infected without an inciting event such as instrumentation
It also should be noted that external compression by a bra or tight clothing can obstruct ducts:
- Is not scientifically founded.
Treatment:
- With early inflammatory mastitis:
  - Patients should feed physiologically (eg, eliminate breast pump usage if possible, and do not continue “overfeeding” on the affected breast):
    - Reducing overstimulation of an engorged or inflamed breast will allow down-regulation of milk production through the FIL receptor
  - Patients should never be counseled to “pump to relieve engorgement” as this prevents FIL from activating and perpetuates hyperlactation
- Patients can use ice and antiinflammatory medication by mouth such as nonsteroidal antiinflammatory drugs and/or obtain pain relief from acetaminophen:
  - Ice is generally the most helpful, but some people also prefer heat for comfort
- Therapeutic ultrasound:
  - Can use thermal energy to reduce inflammation and pain, as can lymphatic drainage
- A supportive bra is necessary during lactation:
  - To prevent dependent lymphedema and back pain
- Massage should be strictly avoided
- If symptoms persist or worsen:
  - Antibiotics should be considered (Table)
- Women should be counseled that there is no medical indication to “pump and dump” while taking these antibiotics:
  - The Relative Infant Dose (RID) estimates an infant’s exposure to a medication through breastmilk and depends on multiple factors including the medication’s plasma concentration, half-life, solubility, and oral bioavailability:
    - In general, medications with RID less than 10% are considered safe