Pathophysiology
Pus is the exudate at an infection site of bacterial or fungal infecting. It is comprised of WBCs and waste from the infection site. If it is in enclosed space it is known as an abscess. Abscesses tend to grow in size and need drainage for resolution.
We can classify breast abscesses as 2 main types:
- Lactational abscess - if related to breastfeeding.
- Non-lactational abscess - if unrelated to breastfeeding. Occurs in smokers.
Now, mastitis may be due to lactation too as bacteria enters the nipple → then ducts, leading to inflammation and infection of the breast. The abscess is usually preceded by mastitis.
🦠 Causative agents
🥇 Staph. aureus (gram positive)
Streptococcal spp. (gram positive)
Enterococcus spp. (gram positive)
Bacteroides spp. and other anaerobic bacteria
Simple penicillins (such as flucloxacillin) are likely to be effective against gram positive bacteria, but with anaerobes they are not as effective. Co-amoxiclav covers anaerobic bacteria and metronidazole of course. /
If allergic to penicillins, clarithromycin/erythromycin may be used.
⚠️ Risk factors
Smoking
Nipple damage (eczema, piercings, candida infection)
Breast cancer
🔍 Diagnosis
It is usually made clinically with Hx and examination. Although USS may aid diagnosis. ➡️
😷 Presentation
It is usually an acute onset of puerperal mastitis with infection. This may present as:
- Fluctuant lump (able to move fluid within the lump during palpation)
- Localised pain & tenderness
- Purulent discharge
- Nipple changes
It is usually unilateral.
- Hardening of breast tissue or skin
- Warmth redness, swelling.
As with any infection there may be systemic symptoms such as fever, malaise, or signs of sepsis.
🧰 Management
The most definitive management is incision and drainage.
Broad-spectrum antibiotics (such as co-amoxiclav or erythromycin/clarithromycin + metronidazole)
⛔️ Complications
Mammary duct fistula - when the skin has a connection to the subareolar breast duct
Sepsis