Jaundice Flashcards
What is jaundice?
Yellow color of the skin and sclerae caused by bilirubin deposits.
When is jaundice visible in adults?
Sclera bilirubin level > 2 mg/dL.
When is jaundice visible in newborn skin?
When bilirubin level > 5 mg/dL.
What percentage of term neonates have jaundice?
60% of term neonates.
What percentage of preterm neonates have jaundice?
80% of preterm neonates.
What is unconjugated bilirubin?
Also known as indirect bilirubin, it binds to albumin, is fat-soluble, crosses the blood-brain barrier, and is toxic at high levels.
What is conjugated bilirubin?
Also known as direct bilirubin, it is water-soluble, excreted in urine and stool, and non-toxic.
What causes increased bilirubin load in newborns?
High hemoglobin concentration, hemolysis, cephalhematoma or bruising, and polycythemia.
What leads to decreased bilirubin conjugation in the liver?
Low uridine glucuronyl transferase activity and Glucuronyl Transferase Deficiency Type 1 (Crigler-Najjar Syndrome).
What are the two main types of jaundice in neonates?
Physiological and pathological jaundice.
When does physiological jaundice appear?
After 24 hours of age.
Why does physiological jaundice develop in neonates?
Due to increased bilirubin load, defective bilirubin conjugation, and increased enterohepatic circulation.
When does pathological jaundice appear?
Within the first 24 hours of age.
What are signs of pathological jaundice?
Jaundice within the first 24 hours, rapid bilirubin increase, jaundice lasting more than 14 days, pale stools, dark urine, and direct bilirubin > 30 mmol/L.
What is breast milk jaundice?
Prolonged jaundice in term infants caused by increased enterohepatic circulation of bilirubin.
When does bilirubin peak in breast milk jaundice?
Bilirubin peaks at 10-15 days of age.
What are common causes of neonatal jaundice?
Physiological jaundice, blood group incompatibility, G6PD deficiency, breast milk jaundice, cephalhematoma, and infections.
What are the two types of hyperbilirubinemia?
Unconjugated (indirect) hyperbilirubinemia and conjugated (direct) hyperbilirubinemia.
What is Crigler-Najjar syndrome type I?
A rare, severe form of hyperbilirubinemia with complete absence of UDPGT, requiring liver transplantation as the only definitive treatment.
How does ABO incompatibility cause jaundice?
Type O mothers may have IgG antibodies that cross the placenta, causing hemolytic disease in babies with blood type A or B.
What is Rh isoimmunization?
Hemolytic disease in newborns caused by Rh incompatibility between mother and baby.
What is jaundice in G6PD-deficient infants associated with?
Lower serum conjugated bilirubin fractions and potential, though uncommon, severe hemolytic attacks.
What are TORCH infections, and why are they relevant in neonatal jaundice?
TORCH (toxoplasmosis, other [syphilis], rubella, cytomegalovirus, herpes) infections can lead to jaundice due to liver involvement.
What are the risk factors for jaundice?
Early jaundice, family history of neonatal jaundice, unrecognized hemolysis, poor nursing, G6PD deficiency, and infections.
What is kernicterus?
A severe condition caused by high bilirubin levels leading to bilirubin encephalopathy.
What are the signs of acute bilirubin encephalopathy?
Lethargy, poor sucking, retrocollis, opisthotonos, and convulsions.
What are the major clinical features of chronic bilirubin encephalopathy?
Athetosis, upward gaze, sensorineural hearing loss, and intellectual deficits.
What is the bilirubin level associated with jaundice on the face?
102 mmol/L.
What bilirubin level indicates jaundice on the lower trunk and thighs?
204 mmol/L.
What are the typical management steps for a jaundiced newborn?
Assess birth weight, gestational age, clinical condition, classify jaundice type, and check for kernicterus.
What is the recommended distance for phototherapy light?
Approximately 45 cm, but closer if necessary without overheating the baby.
Why should phototherapy devices be kept clean and dust-free?
Dust can carry bacteria and reduce the effectiveness of the light.
What supportive care is given during phototherapy?
Shielding eyes, keeping the baby naked, maintaining close light source distance, and regular feeding.
What is the function of phototherapy in neonatal jaundice?
Phototherapy helps break down bilirubin into a form that can be excreted by the body.
What bilirubin level typically necessitates stopping phototherapy?
When bilirubin levels are 50 micromol/L below the phototherapy threshold.
What lab tests are essential for diagnosing jaundice?
Total and direct bilirubin, blood group and Rh, hematocrit, retic count, G6PD assay, Coomb’s test, sepsis screen, liver and thyroid function tests.
What should be done if a newborn with jaundice is unable to feed?
Consider immediate exchange transfusion if phototherapy alone is insufficient.
What is phenobarbital used for in Crigler-Najjar syndrome type II?
It dramatically reduces bilirubin levels, helping confirm the diagnosis.
