Flashcards in Case 8 Deck (76)
What does a history of breastfeeding, normal physical exam, normal newborn screen and later appearance of jaundice suggest?
A diagnosis of breastfeeding-associated jaundice. This is treated with continued breastfeeding and observation.
What is the differential diagnosis for breastfeeding-associated jaundice?
Physiologic jaundice, breast milk jaundice, hemolysis, metabolic, sepsis, biliary atresia, liver disease
What is jaundice?
The physical finding associated with hyperbilirubinemia (either unconjugated or conjugated form). The bilirubin accumulates in the epidermis, resulting in yellow skin, sclera and mucosal. Sixty percent of newborns have sufficiently elevated bilirubin levels to become clinically jaundiced.
75 percent of bilirubin production in newborns occurs when...
...hemoglobin from red blood cells is broken down and converted to unconjugated bilirubin.
How is water-insoluble bilirubin processed in the adult?
Water-insoluble bilirubin binds to albumin and goes to the liver, where it is conjugated with glucuronide by uridine diphosphate glucuronyltransferase (UDPGT). From there, the now-water-soluble bilirubin is excreted into bile. In adults, intestinal flora metabolize the conjugated bilirubin to urobilinogen, then stercobilinogen and it is excreted in the stool.
What happens to bile in neonates?
Neonates lack the GI flora to metabolize bile, so the beta-glucuronidase in the meconium hydrolyzes the conjugated bilirubin back to an unconjugated form. The unconjugated bilirubin is reabsorbed into the bloodstream, where it binds to albumin and is recirculated (enterohepatic circulation). An imbalance of bilirubin production and metabolism causes hyperbilirubinemia.
What are the etiologies of indirect hyperbilirubinemia?
Physiologic jaundice, Jaundice associated with breastfeeding, Hemolysis, Non-hemolytic breakdown of red blood cells, Inborn metabolic disorders.
What is physiologic jaundice?
Seen in full-term, healthy infants. Total bilirubin is less than or equal to 15 mg/dL (less than or equal to 257 mmol/L). Treatment is not required. Usually peaks at 3-4 days of life.
What factors may lead to physiologic jaundice?
Increased bilirubin production (from breakdown of the short-lived fetal red cells), Relative deficiency of hepatocyte proteins and UDPGT, lack of intestinal flora to metabolize bile, high levels of beta-glucuronidase in meconium, minimal oral (enteral) intake in the first two to four days of life resulting in slow excretion of meconium (esp. common with breastfed infants).
What is breastfeeding jaundice?
Early in first week of life. Decreased milk supply leads to limited enteral intake. Increased enterohepatic circulation. Decreased GI motility promotes retention of meconium. Often difficult to distinguish from physiologic jaundice.
What is breast-milk jaundice?
Begins in first 4-7 days of life but may not peak until 10-14 days. Not the result of low milk volume. Cause not completely understood. May be caused by inhibitory substance in breast milk that increases enterohepatic circulation. Can persist for up to 12 weeks.
What is Antibody positive hemolysis?
Direct Coombs or direct antibody test (DAT) positive.
-Rh incompatibility (i.e. mother is Rh neg and baby is Rh pos)
-ABO incompatibility (i.e. mother is type O and baby is type A or B)
-Incompatibilities with minor blood group antigens (much less common)
What is antibody negative hemolysis?
Direct Coombs or DAT negative. Infants with red blood cell membrane defects (eg. spherocytosisor elliptocytosis) or enzyme defects (G6PD or pyruvate kinase deficiency)
What non-hemolytic breakdown of red blood cells can cause jaundice?
Extensive bruising from birth trauma, large cephalohematoma or other hemorrhage (e.g. intracranial), Polycythemia, Swallowed blood during delivery.
What are inborn metabolic disorders that can cause jaundice?
Crigler-Najjar Syndrome, Galactosemia, Hypothyroidism.
What is Crigler-Najjar Syndrome?
Decreased bilirubin clearance caused by deficient or completely absent UDPGT.
How does ethnicity affect jaundice?
-Neonatal jaundice is more common in asian newborns than caucasian
-Less common in black infants than caucasian
-G6PD deficiency - an Xlinked recessive trait that can result in hemolysis and jaundice - is more common in families of mediterranean origin than in other ethnic groups
-Hemoglobinopathies, including sickle cell or one of the thalassemias, are also more common among individuals from the Mediterranean region.
-A family history of anemia or jaundice is important information.
What are additional risk factors for jaundice?
Prematurity, Bowel obstruction, Birth at high altitude
What is Kernicterus?
Most serious outcome of unconjugated hyperbilirubinemia, but rare in healthy term babies without hemolysis.
How do you define Kernicterus?
Pathological term used to describe staining of the basal ganglia and cranial nerve nuclei by bilirubin. Also describes the clinical condition that results from the toxic effects of high levels of unconjugated bilirubin.
What is the etiology of Kernicterus?
In the past, kernicterus among full-term newborn infants primarily resulted from Rh incompatibility (erythroblastosis fettles). Infants typically were severely anemic, in shock, and acidotic, and had total bilirubin levels well above 25 mg/dL (428 umol/L)
What are signs of kernicterus in a seriously affected newborn?
Loss of suck reflex, lethargy, hyperirritability, seizures, possible death.
What are possible sequelae of kernicterus?
Opisthotonus (abnormal posturing that involves rigidity and severe arching of the back, with the head thrown backward), rigidity, oculomotor paralysis, tremors, hearing loss, ataxia.
How do you PREVENT kernicterus?
-Screening for Rh incompatibility and use of anti-Rh immunoglobulin (RhoGAM) have markedly reduced Rh-induced hemolysis and the incidence of kernicterus.
-Tx of unconjugated hyperbilirubinemia with phototherapy also has had an important impact.
Breast milk content:
Breast milk contains the perfect balance of carbs, fats, proteins for human infants, as well as antibodies, growth factors, and other components.
Both human milk and standard infant formulas contain lactose as the major carbohydrate. Lactose intolerance is uncommon in the first year of life.
Represent approx. 50 percent of calories in human milk. Most of the fat in breast milk appears at the end of feeding on each breast, so it is important that infants empty each breast before going to the other.
Combination of whey proteins (70 percent) and casein (30 percent). Formulas contain slightly more protein than human milk. The casein::whey ratio of cow-milk-based formulas varies. Unmodified cow milk contains approx. 3 times the protein content of human milk and approx. 80 percent casein and 20 percent whey proteins. As mentioned, infants should not be given cow's milk ("regular" milk from the dairy section) until one year of age.
Yellowish fluid produced in the first five days postpartum, and gradually replaced by milk. Concentrated source of non-nutritive substances - oligosaccharides, lactoferrin, lysozyme, growth factors, bifidobacteria, and other substances that protect against infection and promote growth.