Icterus in Children
Introduction to Icterus in Children
Icterus, or jaundice, is a yellowing of the skin and sclera due to hyperbilirubinemia. In children, it can be a sign of various underlying conditions, ranging from benign to life-threatening. A thorough clinical examination is crucial for proper diagnosis and management.
Key points:
- Icterus is visible when serum bilirubin exceeds 2-3 mg/dL
- Can be physiological in newborns or pathological at any age
- May indicate hepatobiliary dysfunction, hemolysis, or other systemic issues
History Taking in Icteric Children
A comprehensive history is essential for determining the cause of icterus:
- Age of onset: Neonatal vs. infantile vs. childhood jaundice
- Duration and progression: Acute, chronic, or fluctuating
- Associated symptoms:
- Fever, abdominal pain, weight loss
- Pruritus (suggestive of cholestasis)
- Pale stools, dark urine
- Bleeding tendencies
- Perinatal history: For neonates and infants
- Feeding history: Breastfeeding jaundice, malnutrition
- Medication history: Hepatotoxic drugs
- Family history: Hereditary conditions (e.g., Gilbert's syndrome)
- Travel history: Exposure to infectious agents
Physical Examination of Icteric Children
A systematic approach is crucial:
- General appearance:
- Assess for signs of chronic illness or acute distress
- Note the degree and distribution of jaundice
- Vital signs: Temperature, heart rate, respiratory rate, blood pressure
- Skin examination:
- Assess jaundice in natural light
- Look for petechiae, purpura, or bruising
- Check for signs of pruritus
- Eye examination:
- Scleral icterus
- Kayser-Fleischer rings (Wilson's disease)
- Abdominal examination:
- Hepatomegaly: Size, consistency, tenderness
- Splenomegaly
- Ascites
- Abdominal masses
- Neurological examination:
- Level of consciousness
- Signs of encephalopathy
- Kernicterus in severe neonatal jaundice
Special Considerations in Examining Icteric Children
Certain aspects require particular attention:
- Neonatal jaundice:
- Assess extent using Kramer's rule
- Look for signs of hemolysis (pallor, tachycardia)
- Check for signs of sepsis
- Cholestatic jaundice:
- Inspect stool and urine color
- Look for xanthomas and scratch marks
- Hepatocellular jaundice:
- Assess for signs of liver failure (spider nevi, palmar erythema)
- Look for caput medusae in portal hypertension
Differential Diagnosis of Icterus in Children
Based on the clinical examination, consider the following categories:
- Neonatal jaundice:
- Physiological jaundice
- Breastfeeding or breast milk jaundice
- Hemolytic disease (ABO/Rh incompatibility)
- Sepsis
- Biliary atresia
- Hepatocellular causes:
- Viral hepatitis (A, B, C, E)
- Autoimmune hepatitis
- Wilson's disease
- Drug-induced liver injury
- Cholestatic causes:
- Biliary obstruction
- Progressive familial intrahepatic cholestasis
- Alagille syndrome
- Hemolytic causes:
- Hereditary spherocytosis
- Glucose-6-phosphate dehydrogenase deficiency
- Sickle cell disease
Investigations for Icteric Children
Based on the clinical examination, consider the following tests:
- Initial tests:
- Total and direct bilirubin
- Complete blood count
- Liver function tests (ALT, AST, ALP, GGT, albumin)
- Prothrombin time / INR
- Further investigations:
- Viral hepatitis serology
- Autoimmune markers
- Ceruloplasmin and urinary copper (Wilson's disease)
- Alpha-1 antitrypsin levels
- Newborn metabolic screen results
- Imaging studies:
- Abdominal ultrasound
- Hepatobiliary scintigraphy (HIDA scan)
- Magnetic resonance cholangiopancreatography (MRCP)
- Specialized tests:
- Liver biopsy
- Endoscopic retrograde cholangiopancreatography (ERCP)
- Genetic testing for inherited disorders
Viva Q&A
What is the definition of pathological jaundice in a term newborn?
Pathological jaundice in a term newborn is defined as a total serum bilirubin (TSB) level >12 mg/dL or visible jaundice in the first 24 hours of life.
Name three common causes of unconjugated hyperbilirubinemia in neonates.
1. ABO incompatibility, 2. Rh incompatibility, 3. Glucose-6-phosphate dehydrogenase (G6PD) deficiency.
What is the gold standard test for diagnosing biliary atresia?
The gold standard test for diagnosing biliary atresia is an intraoperative cholangiogram.
At what total serum bilirubin level would you consider phototherapy for a 2-day-old term infant without risk factors?
Consider phototherapy for a 2-day-old term infant without risk factors when the total serum bilirubin level is ≥15 mg/dL (257 μmol/L).
What is the mechanism of action of phenobarbital in treating neonatal jaundice?
Phenobarbital induces hepatic enzymes, particularly UDP-glucuronosyltransferase, enhancing bilirubin conjugation and excretion.
How does breast milk jaundice differ from breastfeeding jaundice?
Breastfeeding jaundice occurs in the first week of life due to insufficient milk intake, while breast milk jaundice occurs after the first week and is caused by substances in breast milk that increase enterohepatic circulation of bilirubin.
What is the most common cause of conjugated hyperbilirubinemia in infants?
The most common cause of conjugated hyperbilirubinemia in infants is biliary atresia.
Name three risk factors for severe hyperbilirubinemia in newborns.
1. Prematurity, 2. ABO or Rh hemolytic disease, 3. Exclusive breastfeeding (particularly if nursing is not going well and weight loss is excessive).
What is the role of HIDA scan in evaluating neonatal cholestasis?
HIDA (hepatobiliary iminodiacetic acid) scan helps differentiate biliary atresia from neonatal hepatitis by assessing bile flow from the liver to the intestine.
What is the appropriate management for a neonate with Rh incompatibility and rapidly rising bilirubin levels?
Management includes intensive phototherapy, intravenous immunoglobulin (IVIG), and preparation for possible exchange transfusion if bilirubin continues to rise despite these interventions.
How does Gilbert syndrome affect bilirubin metabolism?
Gilbert syndrome is characterized by a deficiency in UDP-glucuronosyltransferase, resulting in mild unconjugated hyperbilirubinemia due to decreased bilirubin conjugation.
What is the significance of the direct bilirubin level in neonatal jaundice evaluation?
A direct (conjugated) bilirubin level >20% of the total serum bilirubin or >1 mg/dL suggests cholestasis and requires further evaluation for underlying liver disease.
How does crigler-najjar syndrome type I differ from type II?
Crigler-Najjar syndrome type I is characterized by complete absence of UDP-glucuronosyltransferase activity and does not respond to phenobarbital, while type II has partial enzyme activity and shows some response to phenobarbital treatment.
What is the mechanism of bilirubin-induced neurological dysfunction (BIND)?
BIND occurs when unconjugated bilirubin crosses the blood-brain barrier and causes neurotoxicity, particularly affecting the basal ganglia and auditory pathways.
How does end-tidal carbon monoxide (ETCOc) measurement help in jaundice evaluation?
ETCOc measurement helps identify hemolysis as the cause of hyperbilirubinemia, as increased carbon monoxide production reflects increased heme catabolism.
What is the role of ursodeoxycholic acid in pediatric cholestasis?
Ursodeoxycholic acid is used to enhance bile flow, protect hepatocytes, and improve liver function tests in various cholestatic conditions such as progressive familial intrahepatic cholestasis (PFIC) and biliary atresia.
How does G6PD deficiency contribute to neonatal jaundice?
G6PD deficiency causes increased red blood cell breakdown (hemolysis) when exposed to oxidative stress, leading to increased bilirubin production and subsequent jaundice.
What is the diagnostic criteria for neonatal cholestasis?
Neonatal cholestasis is diagnosed when conjugated bilirubin is >1 mg/dL if the total bilirubin is ≤5 mg/dL, or >20% of total bilirubin if the total bilirubin is >5 mg/dL.
How does zinc-protoporphyrin/heme ratio help in diagnosing the cause of jaundice?
An elevated zinc-protoporphyrin/heme ratio indicates iron-deficient erythropoiesis or lead poisoning, which can help differentiate these conditions from other causes of jaundice.
What is the pathophysiology of kernicterus?
Kernicterus occurs when high levels of unconjugated bilirubin cross the blood-brain barrier and deposit in brain tissues, causing neuronal injury, particularly in the basal ganglia, hippocampus, and cerebellum.
How does albumin administration help in managing severe hyperbilirubinemia?
Albumin administration can increase bilirubin-binding capacity in the blood, potentially reducing the risk of bilirubin crossing the blood-brain barrier and causing neurotoxicity.
What is the role of the Kasai procedure in biliary atresia management?
The Kasai procedure (hepatoportoenterostomy) is used to restore bile flow from the liver to the intestine in biliary atresia by connecting the porta hepatis directly to a loop of jejunum.
How does transcutaneous bilirubinometry compare to serum bilirubin measurement?
Transcutaneous bilirubinometry provides a non-invasive estimate of bilirubin levels and correlates well with serum bilirubin up to 12-14 mg/dL, but may be less accurate in dark-skinned infants or those undergoing phototherapy.
What is the significance of clay-colored stools in a jaundiced infant?
Clay-colored stools in a jaundiced infant suggest biliary obstruction, such as in biliary atresia, as they indicate a lack of bile pigments reaching the intestine.
How does alpha-1 antitrypsin deficiency present with liver disease in children?
Alpha-1 antitrypsin deficiency can present with neonatal cholestasis, elevated liver enzymes, and progressive liver fibrosis. In some cases, it may lead to cirrhosis and liver failure requiring transplantation.
What is the role of exchange transfusion in managing severe neonatal hyperbilirubinemia?
Exchange transfusion rapidly removes bilirubin and sensitized red blood cells, and is used when bilirubin levels approach or exceed exchange transfusion thresholds, or when there's evidence of acute bilirubin encephalopathy despite intensive phototherapy.
How does inspissated bile syndrome contribute to neonatal cholestasis?
Inspissated bile syndrome occurs when thick, viscous bile obstructs the biliary tree, often secondary to hemolysis or total parenteral nutrition. It causes cholestasis and can mimic biliary atresia.
What is the significance of prolonged jaundice (>2 weeks) in a neonate?
Prolonged jaundice beyond 2 weeks of age warrants further evaluation to rule out pathological causes, particularly cholestatic conditions such as biliary atresia, which require timely intervention for optimal outcomes.
How does blue light phototherapy work in treating neonatal jaundice?
Blue light phototherapy works by converting bilirubin in the skin to water-soluble isomers (primarily lumirubin) that can be excreted without liver conjugation, thus reducing serum bilirubin levels.
