User:Richiez/Mastitis

Mastitis, more precisely lactational mastitis or puerperal mastitis is the inflammation of breast in connection with pregnancy, breastfeeding or weaning. It is caused by blocked milk ducts or milk excess and is relatively common; estimates range depending on methodology between 2.6–33%. Less than 0.5% of breastfeeding mothers develop an abscess.

Mastitis does also occur unrelated to pregnancy and lactation, see inflammations and infections of the breast.

For mastitis in animals see mastitis in dairy cattle.

The causes of mastitis are not clear in many cases, it may be caused by blocked ducts and breast emptying problems. Bacterial infection does not play a significant role in the pathology of mastitis.

Some predisposing factors are known but their predictive value is minimal. It appears that proper breastfeeding technique, frequent breastfeeding and avoidance of stress are the most important factors that can be influenced.

Light cases of mastitis are often called breast engorgement, the distinction is overlapping and possibly arbitrary or subject to regional variations.

Classification
Mastitis can be classified as milk stasis, non-infectious or infectious inflammation and abscess. It is impossible to correlate this classification with clinical symptoms, in particular milk stasis, non-infectious and infectious inflammation can be distinguished only by leukocyte count and bacteria culturing. Symptoms like fever, intensity of pain, erythema or rapid onset of symptoms can not be used to distinguish these.

Currently no kind of classification is useful for prognosis or treatment.

Breast abscess
Breast abscess develops only rarely, some sources cite about 0.2-0.4% of breastfeeding women. Known risk factors are age over 30, primiparous and late delivery. No correlation was found with symptoms at presentation or bacterial count at first presentation. Breast abscesses can sometimes develop without preceding mastitis. A causative role of S. aureus could not be confirmed,

Signs and symptoms
Early stages of mastitis can present with local pain, redness, swelling, and warmth, later stages also present with systemic symptoms like fever and flu-like symptoms and in rare cases an abscess or septicemia can develop. However it is pretty common that symptoms develop very quickly without any warning.

Causes
The most frequently assumed causes are inflammation due to blocked milk ducts and milk stasis, oversupply of milk, trauma or mechanical irritation and infection. Milk stasis causes distension of the ducts or alveoli, causing mechanical stress with release of inflammatory cytokines, possibly disruption of tight junctions sealing the ducts and subsequent release of duct contents (stagnated milk) into parenchyma. The detected pathogens are very common species that are detected with almost same frequency in controls and a causative role is assumed to be rare.

Frequently a combination of problems leads to the development of mastitis. Wrong breastfeeding techniques can cause nipple injury, subsequent pain prevents successful breast emptying and leads to milk stasis. Secondary infections are mostly transmitted by contact with relatives or health personal - the mother is usually immune to her own pathogens and is passing her antibodies through breast milk to the baby.

Treatment
Frequent breastfeeding, complete emptying of the breast, supportive treatment and if needed improvement of breastfeeding technique are the best currently known treatments. Adequate fluid intake is important.

In cases of light mastitis massage and application of warm compresses prior to feeding can help as this may aid unblocking the ducts. However in more severe cases of mastitis heat or massage could make the symptoms worse and cold compresses are better suited to contain the inflammation. Cold compresses after or between breastfeeding may be useful to reduce milk production. Warm or cold compresses should not be used for more than 20 minutes at a time.

Antibiotics should be considered if symptoms do not improve after 1-2 days. Measurement of bacterial counts in breast milk appears to be of limited value for the decision when to treat with antibiotics, observation of clinical progress may be more important. In a retrospective analysis evaluating 1827 cases in Germany systemic symptoms resolved in 1826 cases within 25-36 hours and local symptoms resolved within 2-3 days without the use of antibiotics, relying on frequent and regular breastfeeding (every 2 hours) and in some cases additional manual emptying of the breast.

A number of other treatments has been tested such as oxytocin, compresses from cold cabbage and acupuncture, none of those could demonstrate more than marginal benefits.

Treatment of abscesses
Breastfeeding from the affected breast should be continued where possible, antibiotics are frequently prescribed. When necessary ultrasound guided aspiration can be used to relieve the abscess, two or more aspirations may be necessary in some cases. Surgery is rarely needed, it may be considered after antibiotic treatment and repeated aspirations failed to cure the lesion or for abscess size over 3cm.

Weaning
Breast engorgement or mastitis occur frequently after weaning. Extensive tissue remodeling and apoptosis occurs after weaning activating many pro-inflammatory cytokines.

The pregnancy/lactation related hormones usually return to normal levels shortly after weaning but for some women it can take several months and there is an increased risk of rebound lactation and mastitis before hormone levels settle. Avoiding stress is important because the same hormones are also stress hormones. Even after hormone levels settle it takes some time for the breast gland to rebuild to its nonlactating state and it may be particularly prone to mastitis during this time.

Most cases of post weaning mastitis or breast engorgement resolve with supportive treatment. Recurrent post weaning mastitis on the other hand can be an indication of a developing hyperprolactinemia or thyroid disorder and endocrinological examination must be considered.

Cold compresses, lactation inhibiting herbs or medication can be used.

Salvia officinalis is commonly used for weaning. Chasteberry extract can improve prolactin levels which may reduce risk of recurrence but no data is available for use in mastitis.

Prolactin lowering medication has been frequently used for weaning in the past but is much less used since Parlodel (bromocriptine) approval for weaning has been withdrawn in the US over safety concerns. While the question of bromocriptin safety for weaning purposes was never completely resolved it became apparent that it was not very effective in the prescribed dose and did rarely justify the unpleasant side effects.

Other prolactin lowering medications (cabergoline, lisuride) are effective and appear safe but are not widely used for weaning.

Granulomatous (non-puerperal) mastitis is known to occur on average 2 years and almost exclusively up to 6 years after pregnancy. It is an extremely rare condition and believed to be in many cases related to an autoimmune reaction to milk proteins following incomplete inhibition of milk secretion and hyperprolactinemia after weaning.

Prognosis
Most cases should substantially improve within 3 days. Temperature and severity of symptoms at presentation do not predict outcome, women with sore or damaged nipples may need special attention. Risk factors for breast abscess are age over 30, primiparous and late delivery.

Cases that do not completely resolve after 3-5 weeks should raise suspicion of breast cancer.

Breast cancer
Breast cancer may coincide with or mimic symptoms of mastitis. Only full resolution of symptoms and careful examination are sufficient to exclude the diagnosis of breast cancer.

Lifetime risk for breast cancer is significantly reduced for women who were pregnant and breastfeeding. Mastitis episodes do not appear to influence lifetime risk of breast cancer.

Mastitis does however cause great difficulties in diagnosis of breast cancer and delayed diagnosis and treatment can result in worse outcome.

Breast cancer may coincide with mastitis or develop shortly afterwards. All suspicious symptoms that do not completely disappear within 5 weeks must be investigated.

Breast cancer incidence during pregnancy and lactation is assumed to be the same as in controls. Course and prognosis are also very similar to age matched controls. However diagnosis during lactation is particularly problematic, often leading to delayed diagnosis and treatment.

Some data suggests that noninflammatory breast cancer incidence is increased within a year following episodes of nonpuerperal mastitis and special care is required for followup cancer prevention screening. So far only data from short term observation is available and total risk increase can not be judged. Because of the very short time between presentation of mastitis and breast cancer in this study it is considered very unlikely that the inflammation had any substantial role in carcinogenesis, rather it would appear that some precancerous lesions may increase the risk of inflammation (hyperplasia causing duct obstruction, hypersensitivity to cytokines or hormones) or the lesions may have common predisposing factors.

A very serious type of breast cancer called inflammatory breast cancer presents with similar symptoms as mastitis (both puerperal and nonpuerperal). It is the most aggressive type of breast cancer with the highest mortality rate. The inflammatory phenotype of IBC is thought to be mostly caused by invasion and blocking of dermal lymphatics, however it was recently shown that NF-κB target genes activation may significantly contribute to the inflammatory phenotype. Case reports show that inflammatory breast cancer symptoms can flare up following injury or inflammation making it even more likely to be mistaken for mastitis. Symptoms are also known to partially respond to progesterone and antibiotics, reaction to other common medications can not be ruled out at this point.