Mastisis/breast abcesses

Question 1

Define mastisis

Answer 1

infection of the breast parenchyma/mammary duct

Question 2

Define breast abcess

Answer 2

localised collection of pus within the parenchyma

Question 3

Aetiology of mastisis (w/infection)?

Answer 3

• Almost always skin-derived infection arising from the cracking of the nipple
• Most common is Staph. Aureus
o Majority now resistant to methicillin
• Second most common is coagulase-negative Staphylococci
• 40% are polymicrobial

Question 4

Aetiology of mastisis (w/o infection)?

Answer 4

• Underlying duct ectasia/dilation
• Foreign material: nipple piercing, breast implant
• Granulomatous

Question 5

What types of mastisis can you get?

Answer 5

With and without infection

Question 6

What types of breast abcess can you get?

Answer 6

Lactational and non-lactational

Question 7

Aetiology of lactational breast abcess?

Answer 7

 Common organisms: S. aureus, S. epidermidis

 Treated with flucloxacillin

Question 8

Aetiology of non-lactational breast abcess?

Answer 8

 Common organisms: mixed anaerobic/aerobic (bacteroides, S. aureus, S. epidermidis)
 Treated with erythromycin

Question 9

RF for breast abcesses/mastisis?

Answer 9

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

Question 10

Epidemiology of abcesses/mastisis?

Answer 10

•	Mastitis
o	1-10% of lactating women
•	Breast abscess
o	3% of lactating women
o	80% in the first month post-partum

Question 11

Presenting symptoms of breast abcess/mastisis?

Answer 11

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

Question 12

Signs of mastitis/breast abscesses

Answer 12

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

Question 13

Investigations for mastitis/breast abscesses

Answer 13

•	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 14

Management plan for mastitis

Answer 14

o Lactational
 Continue to breast feed/express milk 8-12 times daily
 Analgesia
 Antibiotics
• If severe, prolonged or systemic – Flucloxacillin, Clindamycin (MRSA)

Question 15

Management plan for abcesses

Answer 15

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 16

Possible complications of mastitis/breast abscesses

Answer 16

•	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 17

Prognosis for patients with mastitis/breast abscesses

Answer 17

• Most resolve without serious complications
o 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)