Mastitis/Breast abscesses

Question 1

Define Mastitis

Answer 1

Inflammation of the breast with or without infection

Question 2

Define breast abscess

Answer 2

localised area of infection with a walled of collection of pus

Question 3

Infectious aetiology of Mastitis and breast abscesses

Answer 3

Infectious mastitis + abscesses:
Bacterial: S. aureus, coagulase-negative staphylococci, MRSA
Polymicrobial: aerobes (staph, strep, Enterobacteriaceae, E. coli, Pseudomonas) and anaerobes (peptostreptococcus, Propionibacterium, Bacteroides)
Unusual: Bartonella henselae, mycobacteria, actinomyces, brucella, fungi, parasites, maggot infestation (may be initial presentation of HIV infection)

Question 4

Non-infectious aetiology of mastitis and breast abscesses

Answer 4

Underlying duct ectasia (peri-ductal mastitis or plasma cell mastitis)
Foreign material e.g. nipple piercing, breast implant, silicone)
Granulomatous (lobular) mastitis

Question 5

Describe duct ectasia

Answer 5

Dilated ducts associated with inflammation

The mammary duct-associated inflammatory disease sequence involves squamous metaplasia of lactiferous ducts

Question 6

Risk factors for mastitis and breast abscesses

Answer 6

Female
>30 
Poor breastfeeding technique 
Lactation, milk stasis
Nipple injury, piercings, foreign bodies
Previous episodes
Shaving or plucking areola hair 
Underlying breast condition or defect

Question 7

Symptoms of mastitis/breast abscesses

Answer 7

Fever
Decreased milk outflow
Breast warmth, tenderness, firmness, swelling, erythema
Flu-like symptoms, malaise, myalgia
Breast pain
Breast mass
Fistula
Nipple discharge, inversion/retraction
Lymphadenopathy
Extra-mammary skin lesions

Question 8

Signs of Mastitis/breast abscesses

Answer 8

Fever
Breast warmth, tenderness, firmness, swelling, erythema
Breast mass
Nipple discharge
Lymphadenopathy i.e. axillary lymph nodes
Extra mammary skin lesions

Question 9

Investigations for Mastitis/breast abscesses

Answer 9

USS: hypoechoic lesion (abscess) | May be circumscribed, macro lobulated, irregular or ill define with possible septae
Needle aspiration drainage: purulent fluid
Cytology of nipple discharge or sample from fine-needle aspiration : infection ± malignancy
Milk, aspirate, discharge, or biopsy tissue for culture and sensitivity: Positive culture in infection

Pregnancy: if mastitis develops unexpectedly

Blood culture and sensitivity: Positive culture indicates systemic infection

Mammogram: Non-specific findings in acute phase | May demonstrate underlying lesion if performed after the acute phase

Question 10

Management for lactation mastitis

Answer 10

1. Milk removal (via breast feeding or breast pump/massage)
2. Painkillers e.g. paracetamol
3. Antibiotics e.g. flucloxacillin orally (Clindamycin, trimethoprim for MRSA)
4. Cold compresses

Question 11

Management for breast abscesses

Answer 11

1. Incision and drainage
   a. Needle aspiration if abscess <5cm in diameter
2. IV or oral antibiotic e.g. clindamycin
3. Supportive e.g. paracetamol
4. Smoking cessation

Question 12

Complications of mastitis/breast abscesses

Answer 12

Cessation of breastfeeding
Abscess
Sepsis
Scarring
Functional mastectomy 
Breast hypoplasia 
Necrotising fasciitis
Extra-mammary skin infection
Fistula

Question 13

Prognosis for mastitis/breast abscesses

Answer 13

Most breast infections, including abscesses, will resolve without serious complications when treat promptly and appropriately
Resolution of mastitis 2-3 days after antibiotics is expected
Lactational abscesses tend to be easier to treat than non-lactational abscesses
Most patients with breast infection can continue to breastfeed