Puerperal Mastitis

Initially there may be underlying cellulitis in the connective tissue caused by a blocked duct or poor milk drainage. Infectious mastitis and breast abscess are the result of the introduction bacteria from the infant's mouth and/or throat to the mother's breast. The usual infecting organism is Staphylococcus aureus; although it may also be due to Staphylococcus epidermidis and streptococci.

• Between 2% and 33% of breast feeding women develop lactation mastitis.¹
• The incidence is highest in the first few weeks postpartum, decreasing gradually after that.²
• However, cases may occur as long as the woman is breast feeding.

Risk factors

Women with a past history of mastitis have an increased risk.³There is consensus that nipple fissures, cracks and sores are predisposing factors for mastitis, however the role of feeding frequency is unclear.
Lactation mastitis has also been linked to:

• Primiparity
• Stress
• Improper nursing technique, leading to incomplete emptying of the breast⁴

Mastitis is diagnosed based on clinical symptoms and signs indicating inflammation - breast pain, myalgias and fever.

Symptoms

• This usually presents ≥ 1 week postpartum with only one breast usually affected and often only one quadrant or lobule painful to touch, inflamed, swollen and hot.
• It should be distinguished from congestive mastitis (breast engorgement) which usually presents on second or third day of breast feeding. The complaint is of a swollen and tender breast which is often bilateral and without fever or erythema.

Signs

• Breast examination reveals unilateral oedema, erythema in a wedge-shaped area, and tenderness.
• There may be purulent drainage or pus obtained on aspiration.
• Axillary lymphadenopathy is palpable.

In a breast abscess examination reveals a tender hard breast mass, which may be fluctuant, with overlying erythema.

Detection of pathogens in breast milk is not always possible, and the results of milk culture may not be a useful guide for therapy.
The agents most frequently identified in milk culture are Staphylococcus aureus and coagulase-negative staphylococci spp.⁴ However, these may be contaminants or skin flora.

General advice

Be aware that many women may require emotional support.⁵

• Assessment of breast feeding technique by an appropriately trained, skilled person who can assess feeding pattern, positioning, attachment, sucking behaviour and breast fullness.
• Advise manual expression of milk to empty breast after feeding; this allows proper drainage of the breast.
• Reassure the mother that continuing to breast feed does not present any risk to the infant.
• Suggest supportive therapy such as bed rest, increased fluids, ice packs, analgesia and use of anti-inflammatory agents.
• If the woman is not wishing to continue breast feeding, advise tight breast binding, ice packs and prevention of breast stimulation to suppress lactation and reduce pain.
• Advise that she should stop breast feeding if an abscess develops, although feeding is encouraged to re-start once the abscess is treated.²

Pharmacological treatment

Antibiotics e.g. flucloxicillin or erythromycin should be prescribed.

Surgical

• Incision and drainage of abscess with cavity packed open with gauze.
• Parenteral antibiotics should be administered at the same time, with added coverage for anaerobic bacteria.
• Needle aspiration of the abscess, repeated every other day until pus no longer accumulates, has been suggested as an alternative to open drainage.⁶
• Any persisting mass will need further investigation to exclude sinister causes.

Serious complications occur in cases where treatment is delayed, incorrect or ineffective. These include breast abscess and sepsis:

• Breast abscesses have been reported in 5% to 11% of mastitis cases.⁷
• A case of toxic shock syndrome was reported in Japan, secondary to postpartum mastitis caused by methicillin-resistant Staph. aureus (MRSA).⁸