Breast Abscess

Question 1

What is mastitis?

Answer 1

Mastitis is a painful inflammatory condition of the breast often in lactating women.

Mastitis can be classified as:

=> Non-infectious — breast inflammation due to a non-infectious / idiopathic cause

=> Infectious — infection of breast tissue - occurs by retrograde spread through a lactiferous duct or a traumatized nipple.
Infection via lymphatic or haematogenous spread rare

Question 2

What is a breast abscess?

Answer 2

Breast abscess = localised collection of pus

=> Lactational abscess located in peripheral region of the breast (common in upper and outer quadrant)

=> Non-lactational abscess located in central/subareolar or lower quadrants of the breast

Question 3

What are the causes of mastitis?

Answer 3

1. Milk stasis = the primary cause of mastitis in lactating women.

=> accumulated milk causes an inflammatory response - may progress to infection.

=> Staphylococcus aureus = most common organism in infectious mastitis in breastfeeding women

2. Mastitis + infection in non-lactating women characterised by:

=> central/subareolar:

i) 2nd to peri-ductal mastitis where subareolar ducts are damaged + infected
ii) caused by duct ectasia (age related duct change)

=> peripheral non-lactating infections rare, assoc. with diabetes, rheumatoid arthritis, trauma, corticosteroid treatment and granulomatous mastitis but no underlying cause

=> S. aureus, enterococci, anaerobic bacteria = most common organisms in infectious mastitis in non-lactating women

Question 4

What are the causes of breast abscess?

Answer 4

Severe complication of mastitis

Question 5

What are the predisposing factors for mastitis / breast abscess?

Answer 5

=> Delayed, inadequate treatment of previous mastitis = complications of breast abscess

=> Sudden cessation of breastfeeding with lactational mastitis - without effective milk removal, infectious mastitis can progress to an abscess

=> Immunosuppression i.e. diabetes or HIV, on immunosuppressive therapy = at risk for recurrent breast infections

=> Staph. aureus carriage on skin or mucous membranes (colonization) = implicated in recurrent infections

=> Socio-economic status

=> Poor hygiene

=> Breast abscess more common in primiparous women, >30 years, following post-term delivery

=> Smoking

Question 6

What is the prevalence of breast abscess?

Answer 6

3-11% of women with mastitis = breast abscess

30% of lactating women = mastitis

5-9% of non-lactational mastitis

Question 7

What is the prognosis of breast abscess?

Answer 7

If treated promptly and appropriately = rapid & complete recovery

Recurrence of mastitis or breast abscess is common
=> abscess assoc. with periductal mastitis = high recurrence rate
=> because disease duct often missed/not removed
=> because women continue to smoke (smoking = predisposing factor)

Question 8

What are the complications of breast abscess?

Answer 8

Sepsis

Emotional distress

Inability to breast feed

Death

Question 9

How to diagnose a breast abscess?

Answer 9

Hx of recent mastitis or prior breast abscess

Fever ± general malaise

Painful, swollen lump in breast with redness, heat and swelling of the overlying skin

Exam: lump may be fluctuant with skin discolouration

Question 10

How do diagnose mastitis?

Answer 10

=> A painful breast

=> Fever ± general malaise

=> Tender, red, swollen, hard area of the breast like a wedge-shaped distribution

*symptoms & signs of non-lactational mastitis can mimic breast cancer or a breast abscess:

=> Periductal mastitis: periareolar inflammation ± mass, established abscess, nipple retraction at the site of the diseased duct, central breast pain, ± greenish discharge

=> Granulomatous mastitis: firm, unilateral breast mass, breast distortion, nipple retraction, skin thickening, axillar adenopathy, ulceration, or area of infection with multiple peripheral abscesses

Note: the clinical features of granulomatous mastitis overlap with those of breast cancer and a biopsy is required to confirm the diagnosis.

Question 11

How do you investigate and manage a breast abscess?

Answer 11

Refer urgently to a general surgeon for:

=> Confirmation of the diagnosis by ultrasound

=> Drainage of the abscess by ultrasound-guided needle aspiration or surgical drainage

=> Culture of fluid from the abscess for choice of antibiotic

=> Advise lactating women to continue breastfeeding if possible (including from the affected breast)

Question 12

What are the differential diagnosis for breast abscess?

Answer 12

Conditions that cause breast pain +  assoc. with lactation:
=> Full breasts 
=> Engorged breasts 
=> Blocked duct 
=> Galactocoele 
=> Infection of the mammary ducts 

Conditions that cause breast pain + not assoc. with lactation:
=> Breast cancer 
=> Duct ectasia 
=> Cellulitis 
=> Fibroadenosis 
=> Ruptured breast cyst 
=> Necrotizing fasciitis of the breast 
=> Fat necrosis of the breast 

Conditions that cause nipple pain:
=> Poor infant attachment 
=> Candidal infection of the nipple 
=> Blanching of the nipple 
=> Eczema of the nipple
=> Bacterial infection of the nipple 
=> Raynaud's disease of the nipple