Icterus physiology & phototherapy process


Phototherapy is a therapy based on exposure of the skin to a light source. It is very efficient to reduce bilirubin levels of newborns

What does "icterus" mean ?

Icterus, also called jaundice, is characterised by a yellowing of the skin and the whites of the eyes caused by an accumulation of bile pigment (bilirubin) in the blood, it can be a symptom of gallstones or liver infection or anaemia.

There is an impressive number of different kinds of icterus: the catarrhal jaundice, chronic idiopathic or also haemolytic are just a part of this large amount of varieties.

Examples of icterus :

The pathology we are interested in, is called jaundice of the newborn. This is the jaundice we can see in the first days or even first hours of a baby's life

At birth, all babies have a excess of red blood cells that are metabolised in the course of the first two weeks, into a pigment called bilirubin . In a large number of cases the icterus heals without any treatment.
In the case of a rhesus or ABO incompatibility, the destruction of the red blood cells is at an elevated level and the bilirubin in the blood can reach alarming levels.
Although benign or even normal in some cases, icterus can always revert to a severe case

Types of Icterus and their dangers

The physiologic icterus occurs in practically every premature baby, and in every second term baby. The child needs to be examined by a paediatrician right after birth and just before discharge. When a diagnose of a physiologic icterus is made, the paediatrician will probably not start any treatment.

The retention icterus will only be mentioned for your information.

The third jaundice is called severe jaundice or severe icterus of the newborn. It's a result of the incompatibility we discussed in 1.2. Like its name indicates this is a severe disease which could endanger the baby's life. The baby will have to be admitted to a neonatal service.

The most dangerous icterus is the kernicterus. Due to the incompatibility, the haemolysis start already intrauterine. The excess bilirubin settles down in all tissues and specifically in the grey matter of the brains (hence its name). This disease often ends in a tragic way. In case the baby survives there will be severe neurological after-effects (cerebral paralysis).

What does phototherapy mean ?

Non invasive therapy based on light exposure
Eliminates the bilirubin level in the blood of newborns
The measuring units of the level of bilirubin is the micro mole (µMOL).

The process of the BiliCrystal® technology

Phototherapy works through a process of isomerization (same molecule but different arrangement of the atoms). This process changes the bilirubin into water-soluble isomers that can be passed through the liver.

The infant is placed under lamps imitating the visible part of the light spectrum, between 400 and 700 nanometers. Blue and green's parts of the spectrum with the highest intensity allow to break down the bilirubin so it can be metabolize by the liver and eliminated by urines.

The BiliCrystal® process doesn't generate any excess heat (to avoid the dehydratation of the baby).

The toxicity of bilirubin

The risk of neurological complication exists as of 300 µMOL for normal newborns


When is treatment of the babies jaundice required?

Neonatal jaundice is often seen around the second day after birth, lasting until day 8 in normal births to around 14 in premature births. The jaundice is usually harmless except in those cases: