Jaundice in Newborns 35 Weeks and Older ppt

Jaundice in Newborns

• Importance: Jaundice is common in newborns and can cause serious complications.
• Cause: Yellow skin and eye discoloration, called jaundice, happens when too much bilirubin builds up in the blood. This happens when the level of bilirubin, a product of broken-down red blood cells, exceeds the amount that the protein albumin can carry in the bloodstream.
• Risk: Excess bilirubin can cross the blood-brain barrier and affect the brain.
• Bilirubin-Induced Neurologic Dysfunction (BIND): This is a serious brain condition that can lead to long-term problems, including cerebral palsy, hearing loss, and vision problems.
• Types of Bilirubin: Total bilirubin is made up of unconjugated (indirect) and conjugated (direct) bilirubin. Conjugated bilirubin is water-soluble due to the addition of glucuronic acid in the liver.
• Assessing Jaundice:
  • Use a bright light to check for jaundice.
  • Start at the forehead and move down the body.
  • Measure bilirubin levels at 24 hours of life using a transcutaneous light meter or blood draw.
  • Measure bilirubin levels sooner than 24 hours if the newborn looks jaundiced.

Bilirubin Metabolism

• Newborn Differences: Newborns process bilirubin differently compared to adults.
• Steps:
  • Red blood cells and proteins are broken down, releasing heme into the bloodstream.
  • Bilirubin is conjugated in the liver.
  • Bacteria in the large intestine convert conjugated bilirubin to urobilinogen.

Why Newborns Develop Jaundice:

• Factors:
  • Newborns have a higher hematocrit (50-60% vs. 35-50% in adults), meaning they have more red blood cells
  • Newborns have a faster red blood cell turnover rate (85 days vs 120 days in adults).
• Increased Bilirubin Production: These factors lead to a higher production of bilirubin in newborns.
• Liver Enzyme: The liver enzyme UGT1A1 conjugates bilirubin by adding glucuronic acid.

Newborn Jaundice

• Why is newborn jaundice important?
  • All newborns experience some jaundice.
  • Yellow discoloration of skin and eyes due to bilirubin buildup.
  • Occurs when bilirubin exceeds albumin's binding capacity.
  • Bilirubin unbound to albumin can cross the blood-brain barrier.
  • Bilirubin is a neurotoxin and can cause permanent brain damage.

Bilirubin-Induced Neurologic Dysfunction (BIND)

• Permanent brain damage from bilirubin deposition.
• Acute bilirubin encephalopathy:
  • First stage of BIND.
  • Can be progressive if untreated.
  • Symptoms range from lethargy and decreased muscle tone to seizures, increased muscle tone, coma, and death.
• Kernicterus:
  • Second stage of BIND.
  • Permanent outcome of untreated acute bilirubin encephalopathy.
  • Leads to cerebral palsy, hearing loss, eye movement problems, and dental enamel defects.

Bilirubin Components

• Total bilirubin: Unconjugated bilirubin (indirect) + conjugated bilirubin (direct).
• Conjugated bilirubin: Water-soluble due to the addition of glucuronic acid in the liver.
• Conjugation: The process of adding glucuronic acid.

Assessing Jaundice

• Use skin blanching technique with bright light every 12 hours until discharge.
• Check forehead, then chest for jaundice.
• Routinely measure bilirubin levels at 24 hours via transcutaneous light meter or blood draw.
• Check bilirubin levels earlier than 24 hours if jaundice is visible.
• Jaundice before 24 hours is abnormal.
• Measure bilirubin levels twice before discharge to track the trend.

Bilirubin Metabolism

• Newborns metabolize bilirubin differently than older individuals.
• Differences in metabolic steps make newborns susceptible to jaundice:
  • Red blood cells and proteins are broken down and heme is released into the bloodstream.
  • Bilirubin is conjugated in the liver.
  • Bacteria in the intestines convert conjugated bilirubin to urobilinogen.

Why Do Newborns Develop Jaundice?

• Increased bilirubin production:
  • Newborns have higher hematocrit (50-60% vs. 35-50% in adults).
  • Newborn red blood cell turnover is faster (85 days vs. 120 days in adults).
• Immature liver enzyme activity:
  • UGT1A1 is the enzyme responsible for conjugating bilirubin.
  • UGT1A1 activity is lower in newborns, leading to slower bilirubin processing.

Direct Hyperbilirubinemia (Cholestasis)

• Defined as a direct bilirubin level greater than 1 mg/dL
• Caused by obstructed bile flow
• Results in jaundice, pale stools, and dark urine
• Rare, with an incidence of about 1 in 2500 newborns worldwide

Biliary Atresia

• The most common cause of newborn cholestasis
• Results from idiopathic and progressive fibrosis of the intrahepatic and extrahepatic bile ducts
• Bile becomes trapped inside the liver, leading to cirrhosis and portal hypertension
• Requires urgent surgical intervention within 8 weeks of life to avoid the need for a liver transplant
• Incidence of about 1 in 14,000 newborns, making it the most common indication for pediatric liver transplant

Other Causes of Newborn Cholestasis

• Infections, such as sepsis or urinary tract infections (UTIs)
• Total parenteral nutrition (TPN) can cause biliary sludging
• Metabolic disorders, like galactosemia:
  • Deficiency in one of three enzymes required to digest galactose in human and bovine milk
  • Causes both indirect and direct hyperbilirubinemia

Pathologic Jaundice

• Unconjugated (indirect) hyperbilirubinemia
• Conjugated (direct) hyperbilirubinemia, also known as cholestasis, biliary atresia, infection, TPN, and metabolic disorders

Treatment of Pathologic Indirect Hyperbilirubinemia

• Phototherapy:
  • Uses blue-green light to isomerize indirect bilirubin to lumirubin, which can be excreted in urine
  • Always initiated before a workup for the cause
  • The need for phototherapy is determined by plotting total serum bilirubin on an appropriate graph
  • The phototherapy threshold depends on gestational age, chronological age (age in hours since birth), and the presence of one or more neurotoxicity risk factors
  • A separate graph with lower phototherapy thresholds exists for newborns with neurotoxicity risk factors
• Neurotoxicity risk factors increase the risk of bilirubin-induced neurologic dysfunction (BIND):
  • A rapid rise in bilirubin levels, exceeding 0.2 mg/dL/hr, indicates ongoing hemolysis
  • The total bilirubin level and its relationship to the phototherapy threshold at discharge determine if a newborn requires post-discharge bilirubin checks