ABM clinical protocol #4: Mastitis, revised March 2014

Staphylococcus Infections in Pregnancy: Maternal and Neonatal Risks

Staphylococcus aureus is carried by up to one third of the general population; about 2% are carriers for methicillin-resistant S. aureus (MRSA). Infections caused by the antibiotic-resistant form include skin and soft tissue infections, as well as pneumonia, sepsis, and wound infections. Although the risks of hospital-associated systemic infections have decreased with attention to infection control procedures, serious obstetric illness remains a concern. This article describes the range of MRSA infection in the setting of pregnancy and discusses risks to both mother and newborn associated with active MRSA infection during pregnancy and childbirth. Methicillin-resistant S. aureus remains a risk to mothers and newborns, requiring prompt identification and appropriate management.

ABM Clinical Protocol #26: Persistent Pain with Breastfeeding

A central goal of The Academy of Breastfeeding Medicine is the development of clinical protocols for managing common medical problems that may impact breastfeeding success. These protocols serve only as guidelines for the care of breastfeeding mothers and infants and do not delineate an exclusive course of treatment or serve as standards of medical care. Variations in treatment may be appropriate according to the needs of an individual patient.

Therapeutic Breast Massage in Lactation for the Management of Engorgement, Plugged Ducts, and Mastitis

BACKGROUND

Many women in developed countries do not meet their breastfeeding goals and wean early because of breast pain.

OBJECTIVE

This study aimed to describe clinical response to therapeutic breast massage in lactation (TBML) in the management of engorgement, plugged ducts, and mastitis.

METHODS

Breastfeeding women presenting with engorgement, plugged ducts, or mastitis who received TBML as part of their treatment were enrolled (n = 42). Data collected at the initial visit included demographic, history, and exam data pre-TBML and post-TBML. Email surveys sent 2 days, 2 weeks, and 12 weeks following the initial visit assessed pain and breastfeeding complications. A nested case control of engorged mothers (n = 73) was separately enrolled to compare engorgement severity.

RESULTS

Reasons for the visit included engorgement (36%), plugged ducts (67%), and mastitis (29%). Cases, compared to controls, were significantly more likely to have severe engorgement (47% vs 7%, P < .001). Initial mean breast pain level among those receiving TBML was 6.4 out of 10. Following TBML, there was significant improvement in both breast (6.4 vs 2.8, P < .001) and nipple pain (4.6 vs 2.8, P = .013). All women reported immediate improvement in their pain level. At the 12-week survey, 65% found the massage treatment very helpful. The majority of the women with a new episode of mastitis or plugged duct during the study follow-up found the techniques learned during the office visit very helpful for home management of these episodes.

CONCLUSION

In office, TBML is helpful for the reduction of acute breast pain associated with milk stasis. Mothers find TBML helpful both immediately in-office and for home management of future episodes.

Acute, Subclinical, and Subacute Mastitis

There is a controversy about the origin, definition, and types of acute mastitis, breast pain, and their clinical management. This article reviews current definitions, bacteriological findings, their possible meanings, and their use in clinical settings as well as the latest evidence-based clinical management guidelines.

Severe lactational mastitis: particularities from admission

OBJECTIVE

to identify characteristics of women who have suffered severe lactational mastitis.

METHOD

a descriptive, retrospective, documentary, quantitative study was performed. Data were collected from patient records of 114 hospitalized women from January of 2009 to December of 2013. Data were analyzed by using descriptive statistics.

RESULTS

a higher percentage of severe lactational mastitis was found in young, primiparous women who had completed high school, who had no partner, and did not have a job; 96.5% of women had breast complications before admission and remained hospitalized an average of 4.4 days; at discharge, 23.7% of women had weaned their infants.

CONCLUSION

this study showed that severe lactational mastitis can cause great harm to the woman and the baby.

Determinants of mastitis in women in the CASTLE study: a cohort study

BACKGROUND

Mastitis is an acute, debilitating condition that occurs in approximately 20 % of breastfeeding women who experience a red, painful breast with fever. This paper describes the factors correlated with mastitis and investigates the presence of Staphylococcus aureus in women who participated in the CASTLE (Candida and Staphylococcus Transmission: Longitudinal Evaluation) study. The CASTLE study was a prospective cohort study which recruited nulliparous women in late pregnancy in two maternity hospitals in Melbourne, Australia in 2009-2011.

METHODS

Women completed questionnaires at recruitment and six time-points in the first eight weeks postpartum. Postpartum questionnaires asked about incidences of mastitis, nipple damage, milk supply, expressing practices and breastfeeding problems. Nasal and nipple swabs were collected from mothers and babies, as well as breast milk samples. All samples were cultured for S. aureus. "Time at risk" of mastitis was defined as days between birth and first occurrence of mastitis (for women who developed mastitis) and days between birth and the last study time-point (for women who did not develop mastitis). Risk factors for incidence of mastitis occurring during the time at risk (Incident Rate Ratios [IRR]) were investigated using a discrete version of the multivariable proportional hazards regression model.

RESULTS

Twenty percent (70/346) of participants developed mastitis. Women had an increased risk of developing mastitis if they reported nipple damage (IRR 2.17, 95 % CI 1.21, 3.91), over-supply of breast milk (IRR 2.60, 95 % CI 1.58, 4.29), nipple shield use (IRR 2.93, 95 % CI 1.72, 5.01) or expressing several times a day (IRR 1.64, 95 % CI 1.01, 2.68). The presence of S. aureus on the nipple (IRR 1.72, 95 % CI 1.04, 2.85) or in milk (IRR 1.78, 95 % CI 1.08, 2.92) also increased the risk of developing mastitis.

CONCLUSIONS

Nipple damage, over-supply of breast milk, use of nipple shields and the presence of S. aureus on the nipple or in breast milk increased the mastitis risk in our prospective cohort study sample. Reducing nipple damage may help reduce maternal breast infections.

Treatments for breast abscesses in breastfeeding women

BACKGROUND

The benefits of breastfeeding are well known, and the World Health Organization recommends exclusive breastfeeding for the first six months of life and continuing breastfeeding to age two. However, many women stop breastfeeding due to lactational breast abscesses. A breast abscess is a localised accumulation of infected fluid in breast tissue. Abscesses are commonly treated with antibiotics, incision and drainage (I&D) or ultrasound-guided needle aspiration, but there is no consensus on the optimal treatment.

OBJECTIVES

To assess the effects of different treatments for the management of breast abscesses in breastfeeding women.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trial Register (27 February 2015). In addition we searched African Journals Online (27 February 2015), Google Scholar (27 February 2015), ProQuest Dissertations and Theses Databases (27 February 2015) and the WHO International Clinical Trials Registry Platform (ICTRP) search portal (27 February 2015). We also checked reference lists of retrieved studies and contacted experts in the field as well as relevant pharmaceutical companies.

SELECTION CRITERIA

Randomised controlled trials (RCTs) investigating any intervention for treating lactational breast abscesses compared with any other intervention. Studies published in abstract form, quasi-RCTs and cluster-RCTs were not eligible for inclusion.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed studies for inclusion, assessed risk of bias and extracted data. Data were checked for accuracy.

MAIN RESULTS

We included six studies. Overall, trials had an unclear risk of bias for most domains due to poor reporting. Two studies did not stratify data for lactational and non-lactational breast abscesses, and these studies do not contribute to the results. This review is based on data from four studies involving 325 women. Needle aspiration (with and without ultrasound guidance) versus incision and drainage (I&D) Mean time (days) to complete resolution of breast abscess (three studies) - there was substantial heterogeneity among these data (Tau(2) = 47.63, I(2) = 97%) and a clear difference between subgroups (with or without ultrasound guidance; Chi(2) = 56.88, I(2) = 98.2%, P = < 0.00001). We did not pool these data in a meta-analysis. Two studies excluded women who had treatment failure when they calculated the mean time to complete resolution. One study found that the time to complete resolution of breast abscess favoured needle aspiration over I&D (mean difference (MD) -6.07; 95% confidence interval (CI) -7.81 to -4.33; n = 36), but excluded 9/22 (41%) women in the needle aspiration group due to treatment failure. Another study reported faster resolution in the needle aspiration group (MD -17.80; 95% CI -21.27 to -14.33; n = 64) but excluded 6/35 (17%) women in the needle aspiration group due to treatment failure. A third study also reported that needle aspiration was associated with a shorter time to complete resolution of breast abscess (MD -16.00; 95%CI -18.73 to -13.27; n = 60); however, the authors did not indicate the number of women who were lost to follow-up for either group, and it is unclear how many women contributed to this result. Considering the limitations of the available data, we do not consider the results to be informative. Continuation of breastfeeding, after treatment (success): results favoured the needle aspiration group, but we did not pool data from the two studies because of substantial unexplained heterogeneity (I(2) = 97%). One study reported that women in the needle aspiration group were more likely to continue breastfeeding (risk ratio (RR) 2.89; 95% CI 1.64 to 5.08; n = 60), whereas the other study found no clear difference (RR 1.09; 95% CI 0.97 to 1.22 n = 70). Treatment failure was more common among women treated with needle aspiration compared to those who underwent I&D (RR 16.12; 95% CI 2.21 to 117.73; two studies, n = 115, low quality evidence). In one study, treatment with needle aspiration failed in 9/22 women who subsequently underwent I&D to treat their breast abscess. In another study, treatment with needle aspiration failed in 6/35 women, who subsequently underwent I&D. All abscesses in the I&D group were successfully treated.The included studies provided limited data for the review's secondary outcomes. No data were reported for adverse events. One study (60 women) reported that women in the needle aspiration group were more satisfied with their treatment than women who received I&D to treat their breast abscesses. Incision and drainage (I&D) with or without antibioticsOne study (150 women) compared the value of adding a broad-spectrum cephalosporin (single dose or a course of treatment) to women who underwent I&D for breast abscesses.The mean time to resolution of breast abscess was reported as being similar in all groups (although women with infection were excluded). Mean time to resolution for women who received a course of antibiotics was reported as 7.3 days, 6.9 days for women who received a single dose of antibiotics and 7.4 days for women who did not receive antibiotics. Standard deviations, P values and CIs were not reported and prevented further analysis. No data were reported for any continuation of breastfeeding after treatment (success). For treatment failure, there was no clear difference between the groups of women who received antibiotics (either a single dose or a course of antibiotics) and those who did not (RR 1.00; 95% CI 0.36 to 2.76).Included studies rarely reported this review's secondary outcomes (including adverse events). For post-operative complications/morbidity, there was no difference in the risk of wound infections between the antibiotics and no antibiotics groups (RR 0.58; 95% CI 0.29 to 1.17), irrespective of whether women received a single dose or a course of antibiotics.

AUTHORS' CONCLUSIONS

There is insufficient evidence to determine whether needle aspiration is a more effective option to I&D for lactational breast abscesses, or whether an antibiotic should be routinely added to women undergoing I&D for lactational breast abscesses. We graded the evidence for the primary outcome of treatment failure as low quality, with downgrading based on including small studies with few events and unclear risk of bias.

Mouse models of mastitis - how physiological are they?

Lactation mastitis is a common, but poorly understood, inflammatory breast disease that is a significant health burden. A better understanding of the aetiology of mastitis is urgently required, and will assist in the development of improved prevention and treatment strategies in both human and animal species. Studies in mice have the potential to greatly assist in identifying new drug candidates for clinical trials, and in developing a better understanding of the disease. Mouse models of mastitis involve administration of a mastitis-inducing agent to the mammary gland usually during lactation to examine the host immune response, and progression through to resolution of the disease. There are important variations in the protocols of these mouse models that critically affect the conclusions that can be drawn from the research. Some protocols involve weaning of offspring at the time of mastitis induction, and there are variations in the mastitis-inducing agent and its carrier. Induction of mammary gland involution through weaning of offspring limits the capacity to study the disease in the context of a lactating mammary gland. Administration of live bacteria in an aqueous carrier can cause sepsis, restricting the physiological relevance of the model. Mouse model research should employ appropriately designed controls and closely monitor the health of the mice. In this commentary, we discuss the advantages and study design limitations of each mouse model, and highlight the potential for further development of physiologically relevant mouse models of mastitis.