Jaundice Flashcards
What is jaundice and how is it clinically identified in adults?
Jaundice is characterized by yellow discoloration of the skin and sclera. In adults, examining the sclera is the easiest way to detect jaundice.
Why is detecting jaundice in newborns more challenging?
Detecting jaundice in newborns is more challenging because of the difficulty in seeing the sclera. Therefore, it is easier to detect jaundice in the skin of newborns.
At what bilirubin level does clinical jaundice become evident?
Clinical jaundice becomes evident when bilirubin levels are about 75 µmol.
How does the difficulty of detecting jaundice increase in dark-skinned infants?
Detecting jaundice in dark-skinned infants is more difficult due to the skin pigmentation.
What technique can be used to detect jaundice in newborns with difficulty in seeing the sclera?
Gently pressing on the tip of the infant’s nose and then examining the color of the skin immediately upon releasing the pressure can help detect jaundice in newborns.
How common is jaundice in newborns?
Jaundice is extremely common in newborns, with 60% of term infants and 80% of pre-term infants exhibiting visible clinical jaundice in the first week of life. Additionally, up to 10% of breastfed infants may show jaundice at 1 month of age.
Why is it important to understand the underlying physiology of jaundice in newborns?
Understanding the underlying physiology of jaundice in newborns is crucial for recognizing when jaundice may be pathological and knowing how to investigate and treat it.
What should healthcare providers be able to recognize regarding jaundice in newborns?
Healthcare providers should be able to recognize when jaundice in newborns may be pathological, as opposed to physiological, and require further investigation and treatment.
What are some important aspects of investigating jaundice in newborns?
Investigating jaundice in newborns involves understanding the underlying cause, which may include assessing bilirubin levels, evaluating liver function, and considering any underlying conditions or risk factors.
How should jaundice in newborns be treated?
Treatment for jaundice in newborns may vary depending on the underlying cause and severity. Options may include phototherapy, exchange transfusion, addressing any underlying conditions, and ensuring adequate feeding and hydration.
Where are red blood cells removed from circulation, and what happens to them afterward?
Red blood cells are primarily removed from circulation in the reticulo-endothelial system, mainly in the spleen. After removal, hemoglobin from these red blood cells is broken down into heme and globin.
What happens to globin after the breakdown of hemoglobin?
Globin, a component of hemoglobin, is metabolized into amino acids after the breakdown of hemoglobin.
How is heme metabolized after the breakdown of hemoglobin?
Heme, another component of hemoglobin, is metabolized into biliverdin, which is then converted into bilirubin.
Besides the breakdown of hemoglobin, when else is bilirubin formed?
Bilirubin is also formed during the breakdown of myoglobin and cytochromes, not just hemoglobin.
What is the primary binding protein for unconjugated bilirubin in plasma?
Unconjugated bilirubin in plasma is primarily bound to albumin
How is unconjugated bilirubin primarily removed in the fetus?
In the fetus, most unconjugated bilirubin is rapidly removed by the placenta. However, about 10% is still conjugated in the fetal liver and excreted into the gut.
What happens to unconjugated bilirubin in the fetal gut?
In the fetal gut, unconjugated bilirubin is deconjugated by the enzyme beta glucuronidase and then reabsorbed via the enterohepatic circulation.
How is fetal bilirubin maintained to facilitate its excretion across the placenta?
Most fetal bilirubin is maintained in the unconjugated state to facilitate its excretion across the placenta.
What enzyme is responsible for conjugating bilirubin in the newborn infant?
In the newborn infant, bilirubin is conjugated with glucuronic acid by the enzyme glucuronyl transferase.
How does the handling of bilirubin change after separation from the placenta in newborn infants?
After separation from the placenta, progressively more bilirubin is taken up by the liver and conjugated with glucuronic acid by the enzyme glucuronyl transferase in newborn infants.
What is the characteristic of conjugated bilirubin regarding its solubility and toxicity?
Conjugated bilirubin is water-soluble and is not toxic to brain tissue.
How is conjugated bilirubin excreted from the body?
Conjugated bilirubin is excreted through the bile duct system into the duodenum.
What happens to most of the conjugated bilirubin in the gut?
Most of the conjugated bilirubin in the gut is broken down to stercobilin by bacteria, to be excreted in the stool.
What is the fate of some of the conjugated bilirubin in the gut?
Some of the conjugated bilirubin in the gut is de-conjugated (back into unconjugated bilirubin) and reabsorbed.
How long does the enterohepatic circulation of bilirubin typically remain after delivery?
The enterohepatic circulation of bilirubin typically remains for a few weeks after delivery.
What role does the intestinal enzyme beta glucuronidase play in neonatal jaundice?
Beta glucuronidase, present in breast milk, is responsible for the enterohepatic circulation of bilirubin, contributing to neonatal jaundice, which is more common in breastfed infants.
Why is neonatal jaundice more common in breastfed infants compared to formula-fed infants?
Neonatal jaundice is more common in breastfed infants because breast milk contains the intestinal enzyme beta glucuronidase, which contributes to the enterohepatic circulation of bilirubin.
What happens if there is obstruction to the biliary tree in newborns?
If there is obstruction to the biliary tree, conjugated bilirubin enters the plasma and may be excreted in the urine.
What is the role of bilirubin as an oxygen free radical scavenger?
Bilirubin acts as an oxygen free radical scavenger, helping to neutralize and eliminate free radicals in the body.
How does mild jaundice potentially reduce the risk of damage during labor?
Mild jaundice may reduce the risk of damage by free radicals generated during labor, as bilirubin acts as an oxygen free radical scavenger.
What is the prevalence of increased unconjugated bilirubin levels in newborn infants?
All normal newborn infants have increased amounts of unconjugated bilirubin in their blood, and more than half develop visible jaundice
When does physiological jaundice typically present in newborn infants?
Physiological jaundice typically presents on the second or third day after birth.
When does physiological jaundice usually peak and disappear in newborns?
Physiological jaundice usually peaks by day 3 or 4 and disappears within 7 days in most infants.
What is the typical range of total serum bilirubin (TSB) in formula-fed infants?
The total serum bilirubin (TSB) usually does not exceed 200 µmol/l in formula-fed infants.
What is the potential range of total serum bilirubin (TSB) in healthy breastfed infants?
In some healthy breastfed infants, the total serum bilirubin (TSB) might reach as high as 275 µmol/l.
How is the diagnosis of physiological jaundice typically made in infants?
The diagnosis of physiological jaundice in infants is made by excluding pathological causes of jaundice in infants who are active, feed well, and show no sign of illness.
What are some key characteristics of physiological jaundice in terms of onset and duration?
Physiological jaundice never appears within the first 24 hours of life and seldom lasts beyond 7 days.
What are the recommended interventions for physiological jaundice in infants?
Physiological jaundice typically does not require treatment other than reassuring the mother, encouraging frequent feeds, and monitoring the infant for abnormal signs.
What are some signs that distinguish physiological jaundice from pathological jaundice in infants?
Signs such as activity level, feeding behavior, and absence of other illness symptoms help distinguish physiological jaundice from pathological jaundice in infants.
How long should physiological jaundice typically be monitored before considering further intervention?
Physiological jaundice should be monitored until it resolves within the typical timeframe, usually within 7 days, before considering further intervention.
Physiological jaundice is due to a combination of
- The high haematocrit and shorter red cell survival time, which results in a high
bilirubin production. - Slow hepatic conjugation (immature glucuronyl transferase enzyme).
- The enterohepatic circulation of bilirubin (beta glucuronidase in the intestinal
brush border).
Why are preterm infants especially likely to develop clinical jaundice?
Preterm infants are especially likely to develop clinical jaundice because they have an immature liver with a limited ability to conjugate bilirubin in the first weeks of life.
What is the reason behind some term infants developing ‘idiopathic hyperbilirubinemia’?
Some term infants develop ‘idiopathic hyperbilirubinemia’ because they also have a slow rate of bilirubin conjugation, leading to elevated bilirubin levels.
What is ‘breast milk jaundice’ and who is at risk of developing it?
‘Breast milk jaundice’ is a condition where breastfed infants develop prolonged unconjugated hyperbilirubinemia with jaundice that lasts several weeks. Breastfed infants are at risk of developing this condition.
What may be the underlying cause of ‘breast milk jaundice’?
‘Breast milk jaundice’ may be the result of increased enterohepatic circulation of bilirubin, likely due to the presence of beta glucuronidase in breast milk.
How does the immature liver of preterm infants contribute to clinical jaundice?
The immature liver of preterm infants has a limited ability to conjugate bilirubin in the first weeks of life, leading to an increased risk of clinical jaundice.
What is the difference in toxicity between conjugated and unconjugated bilirubin?
Conjugated bilirubin is not toxic, whereas free unconjugated bilirubin is toxic.
How does unconjugated bilirubin bound to albumin behave differently from free unconjugated bilirubin
Unconjugated bilirubin bound to albumin crosses the blood-brain barrier less readily than free unconjugated bilirubin.
Why is free unconjugated bilirubin able to penetrate cells?
Free unconjugated bilirubin, not bound to albumin, is fat-soluble, which enables it to penetrate cells.
Which areas of the brain are particularly susceptible to damage by unconjugated bilirubin?
The cells of the basal ganglia, mid-brain, and brainstem are particularly susceptible to damage by unconjugated bilirubin.
What are the potential consequences of damage caused by unconjugated bilirubin in the brain?
What are the potential consequences of damage caused by unconjugated bilirubin in the brain?
How does an intact blood-brain barrier influence the risk of bilirubin encephalopathy?
An intact blood-brain barrier reduces the risk of bilirubin encephalopathy by limiting the passage of bilirubin into the brain tissue.
What does the term “Kernicterus” refer to?
“Kernicterus” is the autopsy description of brain tissue stained with bilirubin pigment, indicating bilirubin deposition in the brain.
Why should the term “Kernicterus” not be used to describe neurological signs in live infants?
The term “Kernicterus” should not be used to describe neurological signs (encephalopathy) in live infants because it specifically refers to the autopsy finding of bilirubin-stained brain tissue and not clinical symptoms observed in living individuals.
What is the significance of distinguishing between “Kernicterus” and encephalopathy in live infants?
Distinguishing between “Kernicterus” and encephalopathy in live infants is important for accurate diagnosis and appropriate management of bilirubin-related neurological complications
What are the potential consequences of bilirubin encephalopathy in live infants?
Bilirubin encephalopathy in live infants can lead to neurological impairments such as developmental delays, hearing loss, and motor abnormalities if not promptly diagnosed and treated.
Risk of bilirubin encephalopathy is increased by:
- Very high levels of serum unconjugated bilirubin e.g. severe haemolysis.
- Low serum albumin (as present in preterm or septic infants).
- Very early jaundice (first two days of life).
- Competition for binding sites by drugs e.g. salicylates, sulphonamides, and by
non-esterified fatty acids (NEFA - increased by hypothermia). - ‘Opening’ of the blood-brain barrier in sick infants with hypoxia, acidosis and
infection
Clinical presentation of bilirubin encephalopathy:
- Severe jaundice, especially if jaundice becomes visible in hands and feet.
- Lethargy, with poor feeding and a depressed Moro reflex.
- High-pitched cry with increased tone.
- Tendency to retract head, progressing to opisthotonus and convulsions.
- Deconjugate eye movements with ‘setting sun’ appearance.
- Death.
What are some potential long-term outcomes for survivors of bilirubin encephalopathy?
Survivors of bilirubin encephalopathy may develop late signs of hypotonic or athetoid cerebral palsy, deafness, stained teeth, and some degree of intellectual disability.
What is hypotonic cerebral palsy?
Hypotonic cerebral palsy is a form of cerebral palsy characterized by decreased muscle tone, leading to floppy or weak muscles and difficulties with movement and posture
What is athetoid cerebral palsy?
Athetoid cerebral palsy is a form of cerebral palsy characterized by uncontrolled, involuntary movements, often affecting the hands, feet, face, and tongue.
How does bilirubin encephalopathy contribute to deafness in survivors?
How does bilirubin encephalopathy contribute to deafness in survivors?
What are the potential causes of stained teeth in survivors of bilirubin encephalopathy?
Stained teeth in survivors of bilirubin encephalopathy may result from the deposition of bilirubin pigment in the dental enamel during periods of high bilirubin levels.
classification of jaundice
non- pathological
pathological
What is non-pathological jaundice?
Non-pathological jaundice refers to jaundice that arises as a normal physiological process and does not indicate underlying illness or disease
What is physiological jaundice?
Physiological jaundice is a type of non-pathological jaundice that occurs in newborn infants due to the normal breakdown of red blood cells and the immaturity of their liver function.
What is the significance of physiological jaundice in breastfeeding infants?
Physiological jaundice is commonly seen in breastfeeding infants due to factors such as delayed onset of mature milk production and increased enterohepatic circulation of bilirubin, but it is typically mild and transient.
How is jaundice in clinically well infants characterized?
Jaundice in clinically well infants is typically mild and transient, without accompanying signs of illness or distress.
What is the recommended management for mild, transient jaundice in clinically well infants?
Mild, transient jaundice in clinically well infants typically does not require treatment such as phototherapy and can be managed through measures such as frequent breastfeeding and monitoring of bilirubin levels
Jaundice can be considered pathological if it is:
- Too early: jaundice in 1st 24 hours of life is always pathological.
- Too late: prolonged jaundice (more than day 14 in a term infant, day 21
in pre-term). - Too high: any level above the “phototherapy line”.
- Conjugated:
What are the causes of unconjugated jaundice?
The causes of unconjugated jaundice include
-excessive haemolysis,
-excessive entero-hepatic circulation,
-polycythaemia,
-defective conjugation, and
-haematomas or haemorrhage.
What are some causes of excessive haemolysis leading to unconjugated jaundice?
- Antibody mediated (blood group incompatibility): Rhesus disease, ABO
incompatibility, minor antigens). - Infection, sepsis.
- Haemoglobinopathy (thalassaemia).
- RBC enzyme deficiency (glucose 6 phosphatase deficiency, pyruvate kinase
deficiency). - RBC membrane defects (spherocytosis, ovalocytosis).
What is the association between breastfeeding and unconjugated jaundice?
Excessive entero-hepatic circulation, often seen in breastfeeding infants, can lead to unconjugated jaundice.
What conditions may result in defective conjugation leading to unconjugated jaundice?
Conditions associated with defective conjugation include prematurity, infant of a diabetic mother, hypothyroidism, Gilbert syndrome, and Crigler-Najjar syndrome.
How can haematomas or haemorrhage contribute to unconjugated jaundice?
Haematomas or haemorrhage, such as cephalohaematoma or traumatic delivery-related bruising, can lead to excessive haemolysis and subsequent unconjugated jaundice. Internal haemorrhage, although rare, can also contribute to this condition.
What are the causes of conjugated jaundice?
The causes of conjugated jaundice include
-congenital infections with hepatitis,
-total parenteral nutrition,
-septicaemia/urinary tract infection,
-obstruction, and
-metabolic disorders.
What congenital infections can lead to conjugated jaundice?
Congenital infections with hepatitis caused by viruses (e.g., herpes, CMV, rubella), spirochaetes (e.g., syphilis), and protozoa (e.g., toxoplasmosis) can lead to conjugated jaundice
How can total parenteral nutrition contribute to conjugated jaundice?
Total parenteral nutrition (TPN) can lead to conjugated jaundice, possibly due to factors such as liver injury or cholestasis associated with TPN administration.
What infectious conditions may lead to conjugated jaundice?
Septicaemia and urinary tract infections are infectious conditions that may lead to conjugated jaundice, likely due to liver involvement or cholestasis.
What is a common cause of late-onset obstruction leading to conjugated jaundice?
: Late-onset obstruction causing conjugated jaundice may result from conditions such as choledochal cysts or biliary atresia.
What metabolic disorders can result in conjugated jaundice?
Metabolic disorders such as cystic fibrosis, galactosaemia (very rare), and other inborn errors of metabolism can lead to conjugated jaundice.
How can jaundice be screened for in newborns?
Jaundice can be screened for in newborns using a transcutaneous bilirubinometer (TCB).
How do neonatal units differ in their approach to starting phototherapy based on TCB values?
Neonatal units may differ in their approach to starting phototherapy based on TCB values; some units may initiate phototherapy based solely on TCB values, while others may require confirmation with total serum bilirubin (TSB) before starting phototherapy.
How can blood gas machines aid in clinical decision-making regarding jaundice?
Blood gas machines can provide a bilirubin value within minutes, which can aid in clinical decision-making regarding jaundice. However, these values may not have the same medico-legal status as a validated TSB from an accredited laboratory.
When should a very high TCB reading be confirmed with a TSB?
A very high TCB reading should be confirmed with a TSB to ensure accuracy and reliability before any clinical decisions or interventions are made.
When are investigations typically unnecessary for jaundiced infants?
Investigations are typically unnecessary for jaundiced infants who are asymptomatic, mildly jaundiced, and feeding well.
When should investigations be considered for jaundiced infants?
Investigations should be considered for jaundiced infants if jaundice appears in the first 24 hours or is prolonged, or if the bilirubin level approaches the exchange transfusion level.
What investigations are commonly performed to exclude haemolytic disease or infection in jaundiced infants?
Common investigations to exclude haemolytic disease or infection in jaundiced infants include blood group determination, Coombs test, haemoglobin level assessment, and C-reactive protein (CRP) measurement.
When are levels of conjugated bilirubin and liver function tests typically performed?
Levels of conjugated bilirubin and liver function tests are typically performed if obstructive jaundice is suspected based on clinical presentation and other investigative findings
What is the typical course of treatment for physiological jaundice in infants?
Physiological jaundice in infants typically does not require treatment. Early feeding can help lessen enterohepatic circulation of bilirubin and reduce the need for phototherapy.
How does early feeding help in managing physiological jaundice?
Early feeding helps reduce enterohepatic circulation of bilirubin, which can decrease bilirubin levels and the need for phototherapy in infants with physiological jaundice.
What is the standard treatment for most forms of unconjugated hyperbilirubinemia?
Most forms of unconjugated hyperbilirubinemia respond well to phototherapy, which helps to break down bilirubin and facilitate its excretion.
When is exchange blood transfusion typically required in the treatment of hyperbilirubinemia?
Exchange blood transfusion is rarely required and is typically reserved for severe cases of hyperbilirubinemia that do not respond to phototherapy or when the bilirubin levels reach dangerously high levels.
How is obstructive or conjugated jaundice treated?
Treatment of obstructive or conjugated jaundice involves addressing the underlying condition, which may include surgical interventions for conditions like biliary atresia or antibiotic treatment for congenital infections like congenital syphilis.
How does visible light affect unconjugated bilirubin in the skin?
Visible light, specifically in the blue end of the spectrum (420–460 nm), isomerises unconjugated bilirubin in the skin to a water-soluble, non-toxic isomer known as ‘lumirubin’, which can then be excreted in the stools and urine.
What is the purpose of phototherapy in the treatment of jaundice?
Phototherapy is used to reduce the level of unconjugated bilirubin in the blood, thereby decreasing the risk of kernicterus and minimizing the need for exchange transfusions.
Why is it important to properly cover the eyes during phototherapy?
Properly covering the eyes during phototherapy is essential to prevent retinal damage, as the light used in phototherapy can be harmful to the eyes.
When can eye pads be removed during phototherapy?
Eye pads can be temporarily removed during feeds to allow infants to feed comfortably, but they should be promptly replaced afterward to continue protecting the eyes during phototherapy.
What temperature considerations are important during phototherapy?
It is crucial to check the infant’s temperature regularly during phototherapy to prevent overheating or, less commonly, hypothermia, which can occur due to the heat generated by the phototherapy lights or excessive cooling from the light source.
How should the response to phototherapy be monitored?
The response to phototherapy should be monitored using total serum bilirubin (TSB) or a blood gas machine to measure bilirubin levels at least daily, or more frequently if the jaundice is severe, to assess the effectiveness of treatment.
What happens to the correlation between clinical jaundice of the skin and transcutaneous bilirubin (TCB) levels once phototherapy has been initiated?
Once phototherapy has been started, clinical jaundice of the skin and TCB levels do not correlate with serum bilirubin levels due to the removal of bilirubin from the skin. Therefore, monitoring must be done with blood tests rather than assessment of cutaneous bilirubin.
What is the recommended location for providing phototherapy to newborns?
If possible, phototherapy should be provided beside the mother in the postnatal ward. This setup encourages maternal-infant bonding and allows for continued breastfeeding.
How should breastfeeding be managed in infants undergoing phototherapy?
Mothers should be encouraged to continue breastfeeding frequently while their infants are undergoing phototherapy. Breastfeeding is not contraindicated during phototherapy and can even aid in the elimination of bilirubin.
What is the lifespan of phototherapy lights, and how does this impact their effectiveness?
Phototherapy lights, particularly fluorescent and radiant lights, have a limited lifespan of about 800 hours. After this point, while they may still emit visible light, they may no longer emit the necessary wavelength radiation required for effective phototherapy.
How should the lifespan of phototherapy lights be managed?
All phototherapy lights should be assessed and replaced according to the manufacturer’s guidelines to ensure optimal effectiveness. LED lights typically last longer than fluorescent or radiant lights and may be preferred for this reason.
What is a phototherapy chart?
A phototherapy chart is a guide used to determine the need for phototherapy treatment based on the infant’s age or weight after birth.
How is the infant’s age or weight typically used in a phototherapy chart?
The infant’s age or weight is used as a reference point on the phototherapy chart to determine when phototherapy treatment should be initiated or discontinued.
When should phototherapy be started according to the phototherapy chart?
Phototherapy should be initiated when the infant’s bilirubin level crosses the appropriate line on the phototherapy chart.
How should phototherapy be adjusted if risk factors for encephalopathy are present?
If risk factors for encephalopathy are present, such as prematurity or hemolytic disease, phototherapy should be initiated one line lower than indicated on the chart.
When can phototherapy be stopped according to the phototherapy chart?
Phototherapy may be discontinued when the total serum bilirubin (TSB) level is more than 50 µmol/l below the line corresponding to the infant’s age or weight on the chart.
Why is it important to monitor the bilirubin level again 24-48 hours after stopping phototherapy?
Many infants experience “rebound” jaundice after discontinuing phototherapy. Therefore, it is essential to monitor the bilirubin level again 24-48 hours after stopping phototherapy to ensure that the jaundice does not return to dangerous levels.
What is an exchange blood transfusion?
An exchange blood transfusion is a medical procedure that involves removing a significant portion of an infant’s blood and replacing it with stable adult whole blood
How is an exchange blood transfusion typically performed?
An exchange blood transfusion is usually performed using an umbilical vein catheter or an arterial line, through which the infant’s blood is gradually exchanged with donor blood.
What are the primary purposes of an exchange blood transfusion?
The primary purposes of an exchange blood transfusion are to remove excess bilirubin, correct anemia, and eliminate anti-red cell antibodies present in the infant’s blood
Under what circumstances is an exchange blood transfusion typically performed?
An exchange blood transfusion is typically performed when there is a high risk of bilirubin encephalopathy, a condition where high levels of bilirubin in the blood may lead to brain damage.
What does an exchange transfusion chart indicate?
An exchange transfusion chart provides guidelines and criteria indicating when an exchange transfusion is necessary based on factors such as the infant’s age, weight, and bilirubin levels.
How should risk factors for bilirubin encephalopathy be considered when using an exchange transfusion chart?
When additional risk factors for bilirubin encephalopathy are present, such as haemolysis, sepsis, acidosis, and asphyxia, the next lower line on the exchange transfusion chart should be used as a guideline for determining the need for the procedure.
What is typically involved in a “double volume” exchange transfusion?
A “double volume” exchange transfusion involves replacing approximately twice the infant’s circulating blood volume, which is typically around 80 ml/kg, over a period of 4 hours
What are some risks associated with a double volume exchange transfusion?
Risks associated with a double volume exchange transfusion include hypothermia, hypoglycaemia, sepsis, and the typical risks of blood transfusion, such as incompatibility reactions and infection.
Why is performing an exchange transfusion considered a high-risk intervention?
An exchange transfusion is considered a high-risk intervention due to the potential for complications such as hypothermia, hypoglycaemia, sepsis, and the risks associated with blood transfusion. Therefore, it should only be performed in a medical center with expertise in this procedure
What expertise should be available when considering an exchange transfusion?
When considering an exchange transfusion, it is essential to have access to medical professionals experienced in performing the procedure and managing any associated complications
