A 21 yo woman who is nursing presented with a painful breast.

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This patient had mastitis and blocked milk ducts with superimposed infection.  She was septic with a temp of 39.


An estimated 10% of breastfeeding women develop mastitis, however  only 0.4%  will develop a breast abscess. In the past mastitis was divided into non infectious and infectious, however recently it has been shown that the amounts of pathogenic bacteria in breast milk are notcorrelated to symptoms. In the Kvist study about 15% of women with mastitis are given antibiotics and yet all recovered.  The pathogens are usually staph and strep. It is difficult to determine who has the potential for abscess since many breastfeeding women who wish to donate milk have pathogenic bacteria in their milk and no signs of mastitis.

Most breast infections occur in the first two  months  after delivery or at the time of weaning.

 Teaching point- Mastitis occurs in other animals as well and is a public health concern because milk containing pathogens can cause outbreaks of disease; which notably happens in cow milk contaminated with E. coli

Our patient was unable to express milk and developed sepsis.  She was admitted and placed on IV vancomycin. She underwent an ultrasound guided aspiration of the breast and wan changed to po antibiotics but she continued to worsen and developed a 15 cm breast abscess with necrotic skin overlying it.  A surgical drainage was performed.  Her cultures grew MRSA.



Kvist L, Larsson B, Hall-Lord, M, Stenn a, Schalen C. The role of bacteria in lactational mastitis and some considerations of the use of antibiotic treatment. 2008 International Breastfeeding Journal. 3 (1) 6.

Lynn W, Lockie F, The challenge of mastitis. Archives of Disease in Childhood 2003. 88(9) 818-821.