Breast Abscesses/Mastitis

Question 1

What are breast abscesses and mastitis?

Answer 1

Mastitis = infection of the breast parenchyma/mammary duct

Breast abscess = localised collection of pus within the parenchyma

Question 2

What is the aetiology of mastitis and breast abscesses?

Answer 2

Mastitis
o With our without infection
Infectious
• Almost always skin-derived infection arising from the cracking of the nipple
• Most common is Staph. Aureus - Majority now resistant to methicillin
• Second most common is coagulase-negative Staphylococci
• 40% are polymicrobial

Without infection
• Underlying duct ectasia/dilation
• Foreign material: nipple piercing, breast implant
• Granulomatous

Breast abscess
o Lactational - Common organisms: S. aureus, S. epidermidis (Treated with flucloxacillin)
o Non-lactational - Common organisms: mixed anaerobic/aerobic (bacteroides, S. aureus, S. epidermidis) (Treated with erythromycin)

Question 3

What are the risk factors for mastitis and breast abscesses?

Answer 3

• Nipple piercing
• Young women
• Recent breast surgery
• Lactation
• Staph. Aureus carrier
• Nipple injury
• Smoking (Non-lactational mastitis)

Question 4

What is the epidemiology of mastitis and breast abscesses?

Answer 4

Mastitis
o 1-10% of lactating women

Breast abscess
o 3% of lactating women
o 80% in the first month post-partum

Question 5

What are the symptoms of mastitis and breast abscesses?

Answer 5

• Flu-like symptoms
• Breast pain
• Decreased milk outflow
• Nipple discharge

Question 6

What are the signs of mastitis and breast abscesses?

Answer 6

• Fever
• Breast tenderness
• Breast warmth/firmness/swelling/erythema
• Breast mass
• Nipple inversion
• Lymphadenopathy

Question 7

What are the investigations for mastitis and breast abscesses?

Answer 7

1st line
o Examination
o Breast US (Hypoechoic lesion = abscess)
o Diagnostic needle aspiration (Purulent fluid = abscess)
o Cytology of nipple discharge/aspiration sample
o Milk/aspiration/discharge C+S (Positive culture indicates infection)

Other investigations
o Blood culture
o Mammogram
o Milk leukocyte

Question 8

What is the management of mastitis and breast abscesses?

Answer 8

Mastitis
o Lactational = Continue to breast feed/express milk 8-12 times daily

Analgesia
Antibiotics

If severe, prolonged or systemic – Flucloxacillin, Clindamycin (MRSA)

Abscess
o Drainage - US guided with LA
o Lactational = Continue to breast feed/express milk – will not harm the baby, and engorged breast is a good culture for bacteria

o Non-lactational
Smoking cessation support

Question 9

What are the possible complications of mastitis and breast abscesses?

Answer 9

Cessation of breast feeding
o May exacerbate mastitis
o Increased risk of breast abscess

Abscess (following mastitis)

Sepsis

Scarring

Functional mastectomy

Extra-mammary skin infection

Fistula (1-2%)

Question 10

What is the prognosis of mastitis and breast abscesses?

Answer 10

Most resolve without serious complications
Resolution of mastitis usually 2-3 days after AB therapy

Most women can continue to breastfeed (except if HIV infected)

Reoccurrence
o Increased risk if delayed/inappropriate therapy, poor breastfeeding technique and underlying breast condition
o 50% rate in granulomatous mastitis (rare)