ageing bruising by visual assessment

 

Colour changes in bruises

As red blood cells degrade within a bruise, haemoglobin breaks down into bilirubin and biliverdin, and it is these pigments that pass through a series of colour changes. These are generally from reds through to darker reds/ purples, through to yellows, browns and greens.

haemoglobin breakdown animation

As these pigments resolve, the bruise changes in shape, size and location. Colour changes tend to begin at the margins of a bruise, and thus a large collection of blood will take comparatively longer to pass through a series of colour changes.

Traditionally, opinion regarding the 'age' of a bruise was based in large part on the colour of the bruise, and authors of forensic textbooks gave their own suggested 'timetable' of colour changes with time (summarised in Langlois and Gresham 1991).

There appeared to be a 'consensus' view that red, blue and purple were 'early' colours, greens appearing after 4-7 days and yellow making a late appearance after at least 7 days. Yellow colouration appeared in bruises in calves, however, by 48 hours (McCauseland and Dougherty 1978).

However, it is now clear that the progressive colour changes do not occur in a 'linear' or predictable fashion, and researchers have attempted to identify what, if any, information can be gained from observing colour changes in bruises, and subsequently giving an opinion regarding their likely duration. 

 

Yellowing bruise (several days old)

 

Research into colour changes in bruises

In a widely quoted paper, Langlois and Gresham (1991) examined 369 photographs of 89 subjects (age range 10-100 years, grouped into <65 years and >65 years) presenting to a casualty department (in addition to staff and in-patients) with bruises, the age and cause of which was known. A standard colour chart was included, and in some, but not all cases, repeat photographs were taken.

The key finding of this study was that yellow was not seen in bruises less than 18 hours old, but that not all bruises developed this colour before resolving, and so a bruise without yellow could not be said to be less than 18 hours old.

They also indicated that the colours in bruises were dynamic, and could 'reappear' days later, and that separate bruises on the same person, inflicted at the same time did not necessarily exhibit the same colours, nor undergo equivalent changes in colours over time.

Skin colouration affected the evaluation of bruising, and the study findings were therefore limited to white skinned individuals.

Following this study, Munang and colleagues (2002) looked at bruises in children, and observers were asked to decribe the predominant colour in vivo, and then again at a later date from a colour photograph. Inter-observer variation was also assessed. They found that in only 31% of cases was there complete agreement of colour description by the same observer, between the in vivo examination and assesseing the photograph. Agreement between observers for a bruise examined in vivo was seen in 27% and between photographs of the same bruise in only 24%.

In only 1 in 10 bruises examined at the same time and in the same place did 3 individuals completely agree as to the predominant colour seen.

Reliance on the colour yellow was thus beginning to be questioned, and Hughes et al (2004) showed subjects a series of photographs of bruises in which the yellow 'saturation' was digitally altered, in order to evaluate differences in yellow perception. They found that there was a variability in yellow perception and that an individual's ability to perceive yellow declines with age. All subjects used in this study had normal colour vision, as assessed using Ishihara plates.

 

Research into ageing bruising in children

The Welsh Child Protection Systematic Review Group (http://www.core-info.cardiff.ac.uk/about%20wcpsrg.html) conducted an all language literature review in order to answer the question 'can you age bruises accurately in children?'.

They identified only 3 papers that met their inclusion criteria (out of 1495 articles, of which the full text of 167 papers was reviewed), and concluded that the assessment of the age of a bruise in children was inaccurate (Maguire et al 2005).

Bariciak et al (2003) evaluated inter-observer accuracy of bruise characteristics and age, where the age of the bruise was known, and where abuse or a medical condition predisposing the injured child to bruising were excluded.

They found that there was a significant association between bruise age and colour, with red/blue and purple colours being more common in bruises <48 hours old, and yellow, brown and green bruises being more common in those over 7 days.

However, there was significant overlap between these groups of colours. Estimates of the exact age of the bruise to within 24 hours was poor (only 40%), and inter-observer agreement (Kappa statistic) on colour was similarly poor (κ = -0.03).

Stephenson and Bialas (1996) photographed bruises of children on an orthopaedic ward, where the time of their injury was known, and concluded that different colours appear in the same bruise at the same time, and that not all colours appeared in every bruise. Red could appear any time up to 1 week, whilst blue, brown, grey and purple could appear between 1 and 14 days. Yellow occurred after 1 day and no photograph of a bruise older than 48 hours was considered to be 'fresh'.

Although Carpenter (1990) was primarily looking at bruising patterns, it was noted that colour could not be matched with age except that yellow only appeared in bruises over 48 hours old.

 

Bruises can take minutes to days to develop (Atwal et al 1998 pp.215-230) and a visual assessment of their age is influenced by the light source, the observer, the size of the bruise, the background, and the healing properties of the individual (as well as the amount of blood extravasated and the location of the injury).

 

As Maquire and colleagues have shown, age assessments of bruises are inaccurate, and should only be given in very broad terms, such as 'recent' or 'old' etc.

 

 


 

 

 

ageing bruising by other techniques

 

UV photography

Hempling (1981) described the utility of photographing the skin under UV lighting, in order to demonstrate bruises that were no longer discernable to the naked eye. This phenomenon was ascribed to extravasated blood pigments absorbing more of the visible violet light and/or the effects of the absorbtion of UV radiation by melanocytes that have migrated to the edges of the wound.

This technique was therefore said to be of particular use where the bruise had distinctive or 'clear cut' margins. This theory of melanocyte migration has also been linked with the phenomenon of 'post-inflammatory hyperpigmentation', responsible for the ability to visualise injuries including 'tram-track bruising' months or years after torture, for example (Peel et al 2003).

Barsley et al (1990) note that a major disadvantage of using UV photography is that the observer can not visualise what is being captured on film, and describe a technique of using a video recorder to capture UV images.

Other photographic techniques, including red-free and infrared lighting, have been investigated by Tetley (2005).

 

Transillumination

Horisberger and Krompecher (1997) reviewed the utility of various clinical imaging modalities to identify subcutaneous haematomas that are invisible to the naked eye, and noted that ultrasonography was of limited use because of the echogenicity of subcutaneous adipose tissue, and computed tomography (CT), although sensitive was not specific enough and involved the exposure of the subject to radiation. Magnetic Resonance Imaging (MRI) was the most sensitive and specific imaging modality but was costly and impractical in most cases.

They recommended  the use of transillumination, or 'diaphanoscopy', which relies on the optical principles of light diffusion and absorption, to identify bruises and subcutaneous haematomas. They found the technique to be highly sensitive (95%) and specific (97%) for determining the presence or abscence of subcutaneous invisible haematomas, and recommended its use in the living.

 

Colourimeters - Tristimulus and spectrophotometric methods of assessing the colour of bruises

Colourimetry has been utilised by several researchers in order to evaluate bruises.  Bohnert et al (2000) found a relationship between the colour of a bruise and its location in the cutis/ sub-cutis at post-mortem using spectrophotometry.

Bruises located nearer to the surface appearing red, while those located deeper appeared blue (due to the optical characteristics of the skin and the 'Rayleigh scatter phenomenon' i.e. blue wavelengths of the light being scattered (and reflected) more than the red wavelengths).

 

Yajima and Funayama (2006) analysed bruising in the living using both tristimulus and spectrophotometric measurement, and indicated that single readings were so variable as to be meaningless, but that multiple readings over a series of days showed some promise as a quantitative method of analysing bruises (enabling allocation of bruises to 'recent', 'older', or 'nearly healed' groupings).

 

Alternative light sources

Red blood cells contain haemoglobin, which has an absorbtion peak at 415 nm. Macrophages accumulate within a bruise during the healing process, and convert haemoglobin to bilirubin which has a broad absorption peak maximal at 460 nm. As a bruise ages, a decrease in the absorption of light at 415 nm and an increase of absorption of light at 460 nm would be expected (Hughes et al 2006).

Hughes et al investigated the use of an alternative light source - the Polilight® with units capable of emitting light at 415 nm and 450 nm.  40 bruises of known age (in living subjects) were assessed, and found that the technique was not sensitive enough to detect relative changes in haemoglobin and bilirubin levels. They concluded that the alternative light source used was not able to assist in determining the age of a bruise.

 

 

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