Description of the condition
The benefits of breastfeeding are well known and the World Health Organization (WHO) thus recommends exclusive breastfeeding for the first six months and continuing for one to two years (WHO 2003; WHO 2012). There are, however, many reasons why women stop breastfeeding; one of the most common reasons being complications of lactation (Dener 2003). Amir and colleagues (Amir 2004) indicated that it is difficult to determine the proportion of women who develop breast abscesses following mastitis due to variations in the definition of mastitis. Amir 2004, in a study of women who commenced breastfeeding, found that 0.4% (5/1183) experienced a breast abscess.
Mastitis is an inflammatory condition of the breast that is usually associated with lactation (WHO 2000). Symptoms include breast pain together with malaise, myalgia (muscle pain), sweating, nausea, and vomiting and occasionally, rigours. Common signs include localised pain, redness and engorgement. The primary cause of mastitis is milk stasis, (Hughes 1989). Some of the predisposing factors are limited feeding, poor positioning of the baby, illness of mother or baby, maternal malnutrition and cracked nipples (Amir 2008). In infective mastitis, Staphylococcus aureus and Staphylococcus epidermidis are the commonest causative organisms (Riordan 1990). Mastitis usually occurs during the first six weeks but may occur at any time during lactation (Amir 2008). Conservative management includes efficient removal of milk, with the addition of antibiotics for possible bacterial infections (Baker 2010; Marchant 2002). Other measures include supportive care; rest and fluids, application of heat packs and analgesics. Antibiotics are recommended if symptoms are not improving (Lawrence 2005), although a Cochrane systematic review found insufficient evidence to confirm or refute the use of antibiotics in mastitis (Jahanfar 2012).
A breast abscess is defined as a localised infection with accumulation of fluid in breast tissue that may be acute or chronic. Breast abscesses are usually puerperal (lactational) but can be non-puerperal (Baker 2010). The most common causative organism is Staphloccocus aureus (WHO 2003) although other organisms have been cultured (Bertrand 1991; Dixon 1988; Karstrup 1993). A recent study has suggested that methicillin-resistant Staphylococcus aureus (MRSA) is also beginning to play an important role (Branch-Elliman 2012). Risk factors for developing lactational breast abscesses include: age over 30, first pregnancies, gestational age ≥ 41 weeks and mastitis (Kvist 2005). A breast abscess presents as a hard, tender and sometimes fluctuant mass with overlying erythema (redness of the skin) (Barbosa-Cesnick 2003). It can be diagnosed using ultrasound that demonstrates a hypoechoic lesion and has an irregular border (Dirbas 2011).
Three Cochrane reviews (Crepinsek 2012; Lumbiganon 2012; Mangesi 2010) have illustrated the need for effective treatments for the prevention of mastitis and engorgement, both of which contribute towards the formation of abscesses. It is therefore necessary to examine data on the available treatments for breast abscesses.
Description of the intervention
The goals of treatment of a breast abscess are to ensure quick resolution, maternal and infant safety and maternal satisfaction during treatment with minimal or no interruption to breastfeeding. Approaches to treating breast abscesses include incision and drainage (I & D) under general anaesthesia, needle aspiration which may be a single aspiration with a drain left in or serial aspirations. Antibiotics are recommended following either a needle aspiration or I & D (Abou-Dakn 2010).
Breast milk and fluid samples should be sent for culture to detect the presence of bacteria or resistant pathogens e.g. MRSA (Amir 2004). Treatment with the appropriate antibiotic allows for the continuation of breastfeeding and is encouraged as long as the infant's mouth is not in contact with the abscess. For sensitive organisms, cloxacillin is recommended (Cusack 2011); for MRSA the favoured antibiotic is trimethoprim-sulphamethoxazole. For an infection with oxacillin-resistant Staphylococcus aureus and MRSA infection, vancomycin, clindamycin or rifampin therapy can be prescribed (Walker 2011).
Traditionally, abscesses have been treated by I & D, but recently less invasive procedures are favoured. Where possible, all women with a suspected breast abscess should have an ultrasound, which will be helpful in identifying all pockets of fluid. Management may depend on the state of the overlying skin. For skin that appears normal, evacuation of the abscess is carried out via ultrasound. If the skin over the abscess is thin and shiny or the abscess appears as if it will burst, then I & D is recommended (Dirbas 2011).
Incision and drainage is carried out under general anaesthetic. An incision is made and if necessary, a counter incision is made and a drain placed to allow for drainage of fluid. Daily washing out of the wound may be required until secretions decrease or are clear. By week four, the wound should be closed and without complications. Incision and drainage is recommended when the abscess is large or if there are multiple abscesses. A course of antibiotics is also advised (Abou-Dakn 2010).
3. Ultrasound-guided aspiration
Breast abscesses can also be treated via needle aspiration, using a local anaesthetic and under sterile conditions, with or without ultrasound. Eryilmaz 2005 has shown that abscesses of less than three centimetres in diameter can be treated with single aspiration or serial aspirations until resolution. Failure was seen with abscesses greater than five centimetres in diameter. A probe or a drain is an alternative to using a needle. If the aspirate is viscous then a saline or antibiotic solution can be used to assist with the aspiration. Daily aspirations are recommended until the wound cannot be punctured anymore (< 4 mm). Serial aspirations are done on average between two to nine times. A course of antibiotics should be given (Abou-Dakn 2010).
Regardless of the treatment options exercised by the clinician, the ideal would be for minimal or no interruption of breastfeeding. Failure to allow breastfeeding lends itself to the production of fluid that is viscous, which aggravates engorgement. Breastfeeding ensures drainage of the affected area and speedy resolution of the abscess (Walker 2011).
How the intervention might work
The objective of any of the interventions employed in treating an abscess is to remove the fluid as speedily as possible, hastening resolution, thereby reducing the pain and discomfort and allowing the woman to continue breastfeeding her infant with little or no interruption. Maintaining the integrity of the breast is also important, i.e. that the procedure leaves the woman complication-free, minimal if any scarring, and the function of breastfeeding maintained.
Saleem 2008 found percutaneous ultrasound-guided drainage to be less invasive with a high resolution rate, caused less scarring, had a low complication rate and preserved breast function compared with conventional I & D. Christensen 2005 favoured the use of ultrasound-guided drainage of breast abscesses as it caused less scarring, did not affect breastfeeding, did not require anaesthesia or hospitalisation and was less expensive than surgery. Although I & D has the advantage of breaking down the loculi, the procedure requires a general anaesthetic and between one to three days of hospitalisation and regular dressings. This is thought to cause considerable distress to both mother and baby during what is already a difficult time and the final cosmetic result may be unsatisfactory (Benson 1989; Dixon 1998). Scholefield 1987 expressed a similar view, suggesting that I & D is associated with a prolonged healing time, regular dressings, difficulties in breastfeeding, and the possibility of an unsatisfactory cosmetic outcome. Conversely Jones 1976 and Ajao 1994 found that I & D, curettage and primary closure of the abscess cavity had better scar formation and a reduction of cost of treatment. The cosmetic results are generally good and breastfeeding is encouraged (Dirbas 2011.
Antibiotics and I & D are still seen as standard therapy in managing lactational breast abscesses. More recently, however, there has been an emergence of studies favouring a less invasive technique such as ultrasound-guided needle aspiration to treat breast abscesses.
Opinions on the different treatment modalities for lactational breast abscesses vary. This may be due to the personal preferences or experience of the medical team or the algorithm (standardised decisions) being followed at the time and even the availability of resources. With the emphasis on breastfeeding, it is important that whatever the intervention is, it should not disrupt any momentum gained by the mother with regards to breastfeeding.
Why it is important to do this review
(Mangesi 2010) examined treatments for breast engorgement during lactation with one of its key outcomes being mastitis. The authors reported that most of the studies in the review did not report on the key outcomes. One of the secondary outcomes was breast abscess and one study showed that there was a difference in breast abscesses between the group that received acupuncture and those that did not, however, this study was underpowered and the results were not statistically significant.
(Lumbiganon 2012) looked at antenatal breastfeeding education in increasing breastfeeding duration. As a secondary outcome, they also listed breastfeeding complications such as mastitis and breast abscesses. The authors reported that compared to formal breastfeeding education plus lactation consultation versus routine breastfeeding, education showed no significant difference in mastitis but a significant reduction in nipple pain. (Crepinsek 2012) examined the effect of different interventions for the prevention of mastitis following childbirth. They showed that none of the interventions were effective in preventing mastitis.
Effective interventions for the prevention of engorgement and mastitis are still to be determined. In the absence of these interventions there is an increased likelihood of developing a breast abscess. Currently, there appears to be no consensus on which is the best treatment for lactational breast abscess and to this end there is a need to synthesise existing research to obtain clarity.
To date, no systematic review has been carried out to evaluate surgical or non-surgical, pharmacological or non-pharmacological, invasive or non-invasive interventions, or a combination of treatments, compared with any other intervention, for treating lactational breast abscesses. A systematic review will contribute to evidence-informed decision making in the management of lactational breast abscesses.
To assess the effects of different treatment strategies for the management of breast abscesses in breastfeeding women.
Criteria for considering studies for this review
Types of studies
Randomised controlled trials. Trials using a cluster-randomised or cross-over design will not be included. Quasi-randomised trials will only be included if no randomised controlled trials are identified. Studies only reported as abstracts will be included in the review, but will be excluded from the meta-analysis if insufficient information is present.
Types of participants
Breastfeeding women (exclusive breastfeeding or mixed-feeding) presenting with breast abscesses in one or both breasts. We will include women with co-morbidities (e.g. HIV, diabetes).
Types of interventions
Any intervention, surgical, non-surgical, pharmacological, non-pharmacological, invasive, non-invasive, or a combination of treatments, to treat lactational breast abscesses, compared with any other intervention, surgical, non-surgical, pharmacological, non-pharmacological, invasive, non-invasive, or a combination of treatments, aimed at treating lactational breast abscesses.
Types of outcome measures
- Time to complete resolution of abscess (resolution of abscess will be defined as no recurrence of abscess or need for any intervention). Time is defined by the authors as time of presentation for care or from time of hospitalisation.
- Any continuation of breastfeeding after treatment (success).
- Number of follow-up visits.
- Duration of continuation of breastfeeding after treatment.
- Maternal satisfaction with treatment.
- Post-operative complications/morbidity.
- Duration of hospital stay.
- Adverse events .
Search methods for identification of studies
We will contact the Trials Search Co-ordinator to search the Cochrane Pregnancy and Childbirth Group’s Trials Register.
The Cochrane Pregnancy and Childbirth Group’s Trials Register is maintained by the Trials Search Co-ordinator and contains trials identified from:
- monthly searches of the Cochrane Central Register of Controlled Trials (CENTRAL);
- weekly searches of MEDLINE;
- weekly searches of EMBASE;
- handsearches of 30 journals and the proceedings of major conferences;
- weekly current awareness alerts for a further 44 journals plus monthly BioMed Central email alerts.
Details of the search strategies for CENTRAL, MEDLINE and EMBASE, the list of handsearched journals and conference proceedings, and the list of journals reviewed via the current awareness service can be found in the ‘Specialized Register’ section within the editorial information about the Cochrane Pregnancy and Childbirth Group.
Trials identified through the searching activities described above are each assigned to a review topic (or topics). The Trials Search Co-ordinator searches the register for each review using the topic list rather than keywords.
In addition, we will carry out supplementary searches of African Journals Online. We will also search dissertation databases, trial registries for ongoing studies and Google Scholar. For dissertations we will search ProQuest Dissertations and Theses Databases, Index to Theses in Great Britain and Ireland and DissOnline. For ongoing trials we will search the WHO International Clinical Trials Registry Platform ICTRP Search Portal. See Appendix 1 for search terms to be used in these databases.
Searching other resources
We will check the reference lists of included studies, for relevant citations and contact experts in the field as well as relevant pharmaceutical companies via email in order to find any unpublished studies. We will not apply any language restrictions.
Data collection and analysis
Selection of studies
Two review authors (Hayley Irusen (HI) and Anke Rohwer (AR) or Wilhelm Steyn (WS)) will independently assess for inclusion all the potential studies we identify as a result of the search strategy. We will screen titles and abstracts of search results to exclude irrelevant studies. We will then retrieve full text articles of seemingly relevant studies and examine them to see whether they meet the inclusion criteria. We will resolve any disagreement through discussion and consultation with the third review author (Taryn Young (TY)).
Data extraction and management
We will design a form to extract data (Appendix 2). For eligible studies, two review authors will extract the data using the agreed form. We will resolve discrepancies through discussion. We will enter data into Review Manager software (RevMan 2011) and check for accuracy.
When information regarding any of the above is unclear, we will attempt to contact authors of the original reports to provide further details.
Assessment of risk of bias in included studies
Two review authors (HI and AR) will independently make judgements about risk of bias. Discrepancies will be resolved through discussion and by consultation with the third review author (TY) if not resolved.
(1) Random sequence generation (checking for possible selection bias)
We will describe for each included study the method used to generate the allocation sequence in sufficient detail to allow an assessment of whether it should produce comparable groups.
We will assess the method as:
- low risk of bias (any truly random process, e.g. random number table; computer random number generator);
- high risk of bias (any non-random process, e.g. odd or even date of birth; hospital or clinic record number);
- unclear risk of bias.
(2) Allocation concealment (checking for possible selection bias)
We will describe for each included study the method used to conceal allocation to interventions prior to assignment and will assess whether intervention allocation could have been foreseen in advance of, or during recruitment, or changed after assignment.
We will assess the methods as:
- low risk of bias (e.g. telephone or central randomisation; consecutively numbered sealed opaque envelopes);
- high risk of bias (open random allocation; unsealed or non-opaque envelopes, alternation; date of birth);
- unclear risk of bias.
(3.1) Blinding of participants and personnel (checking for possible performance bias)
We will describe for each included study the methods used, if any, to blind study participants and personnel from knowledge of which intervention a participant received. We will consider that studies are at low risk of bias if they were blinded, or if we judge that the lack of blinding would be unlikely to affect results. We will assess blinding separately for different outcomes or classes of outcomes.
We will assess the methods as:
- low, high or unclear risk of bias for participants;
- low, high or unclear risk of bias for personnel.
(3.2) Blinding of outcome assessment (checking for possible detection bias)
We will describe for each included study the methods used, if any, to blind outcome assessors from knowledge of which intervention a participant received. We will assess blinding separately for different outcomes or classes of outcomes.
We will assess methods used to blind outcome assessment as:
- low, high or unclear risk of bias.
(4) Incomplete outcome data (checking for possible attrition bias due to the amount, nature and handling of incomplete outcome data)
We will describe for each included study, and for each outcome or class of outcomes, the completeness of data including attrition and exclusions from the analysis. We will state whether attrition and exclusions were reported and the numbers included in the analysis at each stage (compared with the total randomised participants), reasons for attrition or exclusion where reported, and whether missing data were balanced across groups or were related to outcomes. Where sufficient information is reported, or can be supplied by the trial authors, we will re-include missing data in the analyses which we undertake.
We will assess methods as:
- low risk of bias (e.g. no missing outcome data; missing outcome data balanced across groups);
- high risk of bias (e.g. numbers or reasons for missing data imbalanced across groups; ‘as treated’ analysis done with substantial departure of intervention received from that assigned at randomisation);
- unclear risk of bias.
(5) Selective reporting (checking for reporting bias)
We will describe for each included study how we investigated the possibility of selective outcome reporting bias and what we found.
We will assess the methods as:
- low risk of bias (where it is clear that all of the study’s pre-specified outcomes and all expected outcomes of interest to the review have been reported);
- high risk of bias (where not all the study’s pre-specified outcomes have been reported; one or more reported primary outcomes were not pre-specified; outcomes of interest are reported incompletely and so cannot be used; study fails to include results of a key outcome that would have been expected to have been reported);
- unclear risk of bias.
(6) Other bias (checking for bias due to problems not covered by (1) to (5) above)
We will describe for each included study any important concerns we have about other possible sources of bias.
We will assess whether each study was free of other problems that could put it at risk of bias:
- low risk of other bias;
- high risk of other bias;
- unclear whether there is risk of other bias.
(7) Overall risk of bias
We will make explicit judgements about whether studies are at high risk of bias, according to the criteria given in the Cochrane Handbook for Systematic Interventions Reviews (Higgins 2011). With reference to (1) to (6) above, we will assess the likely magnitude and direction of the bias and whether we consider it is likely to impact on the findings. We will explore the impact of the level of bias through undertaking sensitivity analyses - see Sensitivity analysis.
Measures of treatment effect
For dichotomous data, we will present results as summary risk ratio with 95% confidence intervals. These data will include resolution of abscess, permanent cessation of breastfeeding and post-operative morbidity.
For continuous data, we will use the mean difference if outcomes are measured in the same way between trials. We will use the standardised mean difference to combine trials that measure the same outcome, but use different methods. These data will include time to complete resolution, duration of hospital stay, number of follow-up visits, duration of temporary cessation of breastfeeding and maternal satisfaction with treatment.
Unit of analysis issues
We will not include cluster-randomised trials.
We will not include cross-over trials as these are not an appropriate study design for the interventions in this review.
Other unit of analysis issues
Studies with two or more than two treatment groups will be included and will be dealt with as recommended by the Cochrane Handbook for Systematic Interventions Reviews (Higgins 2011).When a multi-arm study contributes more than one comparison to a particular meta-analysis we will either combine treatment groups or divide the control group, so that the inclusion of data from the same woman more than once in the same analysis will be avoided.
Dealing with missing data
For included studies, we will note levels of attrition. We will explore the impact of including studies with high levels of missing data in the overall assessment of treatment effect by using sensitivity analysis.
For all outcomes, we will carry out analyses, as far as possible, on an intention-to-treat basis, i.e. we will attempt to include all participants randomised to each group in the analyses, and analyse all participants in the group to which they were allocated, regardless of whether or not they received the allocated intervention. The denominator for each outcome in each trial will be the number randomised minus any participants whose outcomes are known to be missing.
Assessment of heterogeneity
We will assess statistical heterogeneity in each meta-analysis using the T², I² and Chi² statistics. We will regard heterogeneity as substantial if the T² is greater than zero and either the I² is greater than 30% or there is a low P value (less than 0.10) in the Chi² test for heterogeneity. For significant heterogeneity, we will use the random-effects model or report results narratively.
Assessment of reporting biases
If there are 10 or more studies in the meta-analysis we will investigate reporting biases (such as publication bias) using funnel plots. We will assess funnel plot asymmetry visually. If asymmetry is suggested by a visual assessment, we will perform exploratory analyses to investigate it.
We will carry out statistical analysis using the Review Manager software (RevMan 2011). We will use fixed-effect meta-analysis for combining data where it is reasonable to assume that studies are estimating the same underlying treatment effect: i.e. where trials are examining the same intervention, and the trials’ populations and methods are judged sufficiently similar. If there is clinical heterogeneity sufficient to expect that the underlying treatment effects differ between trials, or if substantial statistical heterogeneity (if the T² is greater than zero and either the I² is greater than 30% or there is a low P value (less than 0.10) in the Chi² test for heterogeneity) is detected, we will use random-effects meta-analysis to produce an overall summary if an average treatment effect across trials is considered clinically meaningful. The random-effects summary will be treated as the average range of possible treatment effects and we will discuss the clinical implications of treatment effects differing between trials. If the average treatment effect is not clinically meaningful, we will not combine trials.
If we use random-effects analyses, the results will be presented as the average treatment effect with 95% confidence intervals, and the estimates of T² and I².
Subgroup analysis and investigation of heterogeneity
If we identify substantial heterogeneity, we will investigate it using subgroup analyses and sensitivity analyses. We will consider whether an overall summary is meaningful, and if it is, use random-effects analysis to produce it.
We plan to carry out the following subgroup analyses.We will assess different definitions for the primary outcome.
- Primigravidae versus multigravida.
- Catheter aspiration (abscess > 3 cm) versus needle aspiration (abscess < 3 cm).
- Women under 30 years of age versus those over 30 years of age.
- Urban settings versus rural settings.
- Co-morbidities versus no co-morbidities.
- Exclusive breastfeeding versus mixed breast-bottle feeding.
- High-income settings versus low-income settings.
We will use the following outcomes in subgroup analysis.
- Time to complete resolution of abscess.
- Any continuation of breastfeeding after treatment.
We will assess subgroup differences by interaction tests available within RevMan (RevMan 2011). We will report the results of subgroup analyses quoting the χ2 statistic and P value, and the interaction test I² value.
We will perform sensitivity analysis on primary outcomes, to see what effect the exclusion of studies with high risk of bias (for allocation concealment, and incomplete outcome data) might have on the overall result of the meta-analysis.
As part of the pre-publication editorial process, this protocol has been commented on by four peers (an editor and three referees who are external to the editorial team), a member of the Pregnancy and Childbirth Group's international panel of consumers and the Group's Statistical Adviser.
This document is an output from a project funded by the UK Department for International Development (DFID) for the benefit of developing countries. The views expressed are not necessarily those of DFID.
Appendix 1. Search terms for Google Scholar, African Journals Online, ICTRP and dissertation databases
African Journals Online, ICTRP and dissertation databases
(breastfeed* OR lactation OR lactational OR lactating OR puerper* OR postpartum OR post-partum OR postnatal) AND abscess* AND (manage* OR therap* OR treat* OR intervent* )
(breastfeed* OR lactation OR lactational OR lactating OR puerper* OR postpartum OR post-partum OR postnatal) AND abscess* AND (manage* OR therap* OR treat* OR intervent* ) AND random*
Appendix 2. DATA extraction form
SYSTEMATIC REVIEW - LACTATIONAL BREAST ABSCESS
STUDY ELIGIBILITY FORM
Chapter 8 Assessing risk of bias in included studies. Higgins JPT. Cochrane Handbook for Systematic Review of Interventions.
RESULTS PER OUTCOME
Primary outcome 1:
Primary outcome 2:
Primary outcome 3:
Secondary outcome: 1
Secondary outcome 2
Secondary outcome 3
Secondary outcome 4
Secondary outcome 5
Contributions of authors
Hayley Irusen is guarantor for the review and she developed the protocol, Anke Rohwer and Taryn Young gave input on the draft. Professor Daniël Wilhelm Steyn commented on the clinical aspects of the protocol.
Declarations of interest
Sources of support
- Centre for Evidence-based Health Care, Faculty of Medicine and Health Sciences, Stellenbosch University, South Africa.
- Department for International Development, UK.