Fifty shades of green
- Conflict of interest: None declared.
Arguably, green has always been considered a dominant colour in medicine and is often found to be the colour of choice to decorate hospitals. As early as 1914, Sherman reported feeling discomfort in working in white operating rooms and advised that ‘green should be chosen for the colour of the floor and the wainscot. A room painted in this way, the floor and the walls for six feet from the floor, bright spinach green, and all above a glazed white, was matched for use against a room painted a glazed white floor, walls and ceilings. No-one who could get into the green room to do an operation ever went into the white room’.[1] In 1921, Ludlow reported green as a restful colour and, when used in lighter shades, makes an ‘agreeable surrounding’.[2]
However, although reported as restful and agreeable, there is also something unsettling and a little sinister about the colour green. A clinician's antennae start to quiver when ‘green’ is mentioned as part of an infant's history or is noted on a physical examination: blue-green pus of a bacterial infection, the yellowish-green sclera of biliary atresia, dark green blood found in sulfhaemogolbinaemia, the greenish nails of chloronychia and the greenish hue of the skin in hypochromic anaemia (historically known as chlorosis); the list can go on.
And with the colour green comes its multitudes of shades. Wikipedia, the ‘renowned encyclopaedia’, has 73 pages in the category ‘shades of green’.[3] As clinicians, we try to dig deep into the symptomatology to narrow down our differential diagnosis. With a time-tested approach such as this comes a possibility of teasing out the specific shades of a colour, allowing it to be a diagnostic clue or to help exclude a condition. With this viewpoint, we would like to apply this to the frequent and often perplexing condition of vomiting in the newborn.
Vomiting in a newborn infant is a very common reason for parents to present to general practitioners and paediatricians and has been reported as the reason to visit the emergency departments in up to 36% of presentations.[4] Infants vomit more frequently compared with older children as they have an ‘immature gastro-oesophageal sphincter, their, position is mainly supine and liquid feeds are easier to regurgitate than solids’.[5]
Although a source of great stress for parents, the aetiology of vomiting may or may not be clinically significant. The causes are myriad and include overfeeding and gastro-oesophageal reflux, cows milk protein allergy, infections, metabolic disorders and surgical conditions.[5] The timing of onset of vomiting is a useful, although not definitive, indicator of causation, with vomiting in the first few days suggestive of a congenital intestinal atresia and later in the neonatal period suggestive of Hirschprung disease or intestinal malrotation.[6]
Bilious vomiting or gastric aspirates in a sick infant with an obvious intra-abdominal pathology usually arouses clinical suspicions and precipitates a series of tests and ultimately a diagnosis. Unfortunately, when the infant is apparently well, a single bilious vomit may be unremarkable, and clinicians may not recognise the clinical significance. The appearance of the well newborn who has fed well until recently, is well hydrated and normally perfused and with wet nappies has the potential to lull one into a false sense of security. This presentation may dissuade the clinician from referring the infant to a distant hospital and subjecting him or her to the radiation exposure of an upper gastrointestinal contrast study as not everyone with such a presentation will have intestinal obstruction. However, the life-threatening condition of malrotation should not be forgotten.
Malrotation of the intestine is a congenital condition that results from failure of the intestines to rotate and fix normally. Although not necessarily a problem in itself, it can lead to intestinal obstruction or worse – a volvulus. It is estimated to occur in approximately 1 in 500 live births.[7] The only pointer towards a diagnosis of malrotation in a newborn could be bilious vomit. A common misconception is that the abdomen should be distended if the bowel is obstructed. As the volvulus in malrotation involves very proximal bowel, the abdomen may be paradoxically scaphoid in this setting.
Appropriate action can often be delayed, even when bilious vomiting is suspected. In a questionnaire sent to neonatologists, 80% agreed to admit a newborn with a single episode of bilious vomiting for observation, although 19% felt that observation on the post-natal ward was appropriate; however, more than 50% did not consider it appropriate to order an upper gastrointestinal contrast study.[8] We suggest, from our experience, to differ with the approach of observation and believe that any bilious vomit or gastric aspirate in a newborn is a sign of intestinal obstruction unless proven otherwise and in a well newborn mandate the exclusion of malrotation.
Unfortunately, there is no consensus with regards to the precise shade of green required to diagnose vomit as being bilious. An individual's perception of shade may well be different to others. Walker reported that many general practitioners and parents do not recognise green as the colour for bile, and conversely, yellow vomit does not exclude intestinal obstruction.[8] At the other end of the spectrum, colour charts have been developed to confidently identify and act on a bilious aspirate with potential to reduce over-recognition of bile and unnecessary interruptions in feeding.[9]
Lastly, another complication of this ‘shady’ topic is the issue of colour blindness. A review article reported colour vision deficiencies in the medical profession. Of the 40 doctors in this study, 18 reported difficulties with detecting blood or bile in urine, faeces, sputum or vomit.[10] In another study, breakdown of the ability of staff to correctly identify bile colour in neonates showed that 74% of the female staff correctly identified bile, as compared to a dismal 34% of the male staff, and mothers (45%) did better than fathers (35%).[11]
Having recently witnessed death, devastation and catastrophe of Short Gut Syndrome that followed only a few hours after a bilious vomit in an apparently healthy newborn with malrotation, we were compelled to emphasise this oft-repeated dictum. Our view point is that a healthy looking newborn with a single vomit that is neither milky nor has blood in it should be suspected of having bile and requires a careful assessment by experienced practitioners. Bilious vomit or its suspicion certainly necessitates exclusion of malrotation.
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