NEONATOLOGY 2

What is the most common sequela that needs to be observed in a newborn who recovered from NEC?

Presence of stricture

What is the most common life-threatening emergency of the gastrointestinal tract in the newborn period, particularly in preterm infants?

Necrotizing enterocolitis (NEC)

Which areas of the intestine are most commonly involved in NEC?

Distal ileum and proximal colon

What are the three major risk factors for NEC?

Prematurity, bacterial colonization of the gut, formula feeding

Name some other contributing factors to the development of NEC.

Intestinal immaturity, microbial dysbiosis, mucosal ischemia, genetic predispositions

Which term or preterm infants are at higher risk of NEC based on age of onset?

The smaller the baby, the earlier the onset (age of onset inversely related to gestational age)

List the early non-specific signs of NEC.

Lethargy, temperature instability, abdominal distention, feeding intolerance, bloody stools

What radiographic finding confirms the diagnosis of NEC?

Pneumatosis intestinalis (air in bowel mucosa)

What radiographic sign indicates severe NEC?

Portal venous gas

What radiographic sign indicates bowel perforation in NEC?

Pneumoperitoneum (football sign)

What is the treatment for suspected NEC (Bell Stage I)?

NPO for 3 days and antibiotics for 7 days

What is the treatment for definite NEC (Bell Stage II)?

NPO 3–7 days and antibiotics for at least 10 days

What additional treatment may be needed for moderate NEC with portal gas?

Supportive care including extended NPO + antibiotics 14 days

What is the treatment for NEC with bowel perforation (Stage IIIB)?

NPO + antibiotics + surgery

What is the benign variation of Hirschsprung disease?

Meconium plug

Which condition is commonly seen in 90% of patients with cystic fibrosis?

Meconium ileus

What are the clinical features of meconium ileus?

Bilious emesis, abdominal distention, no passage of meconium (distal ileum involvement)

When may surgery be required in meconium peritonitis?

Persistent obstruction, ongoing peritonitis, or presence of abdominal mass

At what bilirubin level is jaundice visible in a newborn?

5 mg/dL

Which form of bilirubin is fat-soluble, crosses the blood-brain barrier, and is potentially neurotoxic?

Unconjugated (indirect) bilirubin

Which form of bilirubin is water-soluble, does not cross the blood-brain barrier, and is always pathologic?

Conjugated (direct) bilirubin

When does physiologic jaundice typically appear in a term newborn?

2–3 days of life

What total serum bilirubin levels are considered pathologic in term and preterm neonates?

Term: >12 mg/dL, Preterm: >15 mg/dL

What is the most common cause of severe hyperbilirubinemia in newborns?

Hemolytic disease of the newborn

Name some inherited hepatic causes of hyperbilirubinemia.

Crigler-Najjar type 1 & 2, Gilbert syndrome, Rotor syndrome

What is the difference between breastfeeding-associated jaundice and breast milk jaundice?

Breastfeeding-associated occurs early due to low intake; Breast milk jaundice occurs later and may persist up to 3 months

What is the primary goal of phototherapy in neonatal hyperbilirubinemia?

Prevent bilirubin encephalopathy by keeping bilirubin levels below pathologic threshold

Which wavelength of light is most effective in phototherapy for newborn jaundice?

Blue light, 420–470 nm

When is exchange transfusion indicated in hyperbilirubinemia?

If intensive phototherapy fails and serum bilirubin ≥25 mg/dL

What is the role of IVIG in neonatal hyperbilirubinemia?

Adjunctive therapy for iso-immune hemolytic disease to reduce RBC destruction

What are the three main mechanisms causing neonatal anemia?

Blood loss, increased RBC destruction, underproduction of erythrocytes

What laboratory test is used to distinguish between hypoproliferative anemia and hemolysis in a newborn?

Reticulocyte count

If a newborn has low reticulocyte count, what type of anemia is likely?

Hypoproliferative or congenital disease

If a newborn has normal or high reticulocyte count, what further test is requested to differentiate the cause?

Coombs test

What does a positive Coombs test indicate in a newborn?

Hemolytic disease

What does a negative Coombs test indicate and what should be checked next?

Check MCV; low MCV suggests alpha-thalassemia, normal/high MCV → check PBS

What is the minimum hematocrit level recommended in a newborn before considering transfusion?

40% (ideally 45-60%)

What factors influence the decision to transfuse an anemic newborn?

Severity of symptoms, hemoglobin levels, comorbidities, ongoing blood loss, anticipation of hemolysis, planned surgery

What is hemolytic disease of the fetus and newborn also called?

Erythroblastosis Fetalis

What is the most common cause of clinically significant hemolytic disease in newborns?

ABO incompatibility

Which Rh antigen is most commonly involved in Rh incompatibility?

D antigen

Why is the first Rh+ baby usually not affected in an Rh- mother?

First pregnancy induces IgM antibodies which do not cross the placenta

When should Rhogam be administered to an Rh- mother?

At 28 weeks GA and at birth of Rh+ baby

What is the most severe manifestation of Rh hemolytic disease?

Hydrops fetalis

Describe hydrops fetalis in the newborn.

Marked edema, effusion in serous cavities, gross hepatosplenomegaly, large edematous placenta, may result in stillbirth

What is icterus gravis?

Deep jaundice appearing

When does congenital hemolytic anemia typically present in Rh disease?

End of first week of life or later, mildest form, usually no jaundice

What test confirms Rh incompatibility in the newborn?

Direct Coombs test positive on infant RBCs

What type of maternal antibody crosses the placenta and causes hemolysis in Rh disease?

IgG

How is ABO incompatibility different from Rh incompatibility in severity?

ABO is usually milder due to antigen expression in all tissues diluting maternal antibodies

Which laboratory findings may be seen in ABO incompatibility?

Microspherocytosis, polychromasia, spherocytes, reticulocytosis, increased RBC count

What is polycythemia in a newborn?

Hemoglobin >20 g/dL or hematocrit >65%

Name primary and secondary causes of neonatal polycythemia.

Primary: increased fetal erythropoietin; Secondary: transfer of RBC mass (e.g., twin-to-twin transfusion)

What is the calculation formula for partial exchange transfusion in polycythemia?

Blood volume exchanged = (Observed Hct − Desired Hct) / Observed Hct × Infant blood volume

What vitamin is required for γ-carboxylation of glutamic acid residues in coagulation factors?

Vitamin K

Which coagulation factors are vitamin K dependent?

II, VII, IX, X and proteins C, S, Z

What are the three types of Vitamin K deficiency in newborns?

Early (

Which type of Vitamin K deficiency is associated with maternal drugs?

Early type

Which type of Vitamin K deficiency occurs in exclusively breastfed infants 2–7 days of life?

Classic type

What are common bleeding manifestations of Vitamin K deficiency?

GIT bleeding, intracranial hemorrhage, skin bruising, post-circumcision bleeding

How is Vitamin K deficiency treated in newborns?

IM injection of 1 mg vitamin K at birth

What is the prevalence of inborn errors of metabolism (IEM) globally?

3–5%

What is a classic presentation clue for inborn errors of metabolism in neonates?

Vomiting, breathlessness, tachypnea, seizures, floppiness, peculiar body/urine odor

Match these specific smells to IEM: Sweaty feet, Maple syrup odor, Musty odor, Male cat urine

Sweaty feet → Isovaleric acidemia/Glutaric aciduria; Maple syrup odor → Branched chain AA; Musty odor → PKU; Male cat urine → Glycinuria

Define hypoglycemia in infants of diabetic mothers (IDM).

Blood glucose

What are common clinical features of hypoglycemia in IDM?

Sweating, lethargy, irritability, jitteriness, tachycardia, tremors, cyanosis, apneic spells, seizures

How is symptomatic hypoglycemia in IDM treated initially?

10% dextrose 2 mL/kg IV bolus followed by 4–10 mg/kg/min IV infusion until blood sugar >40 mg/dL

Which medications are used if hypoglycemia persists after 12–24 hrs of IV glucose?

Prednisolone or Hydrocortisone, Glucagon, Diazoxide

Name maternal and perinatal causes of early neonatal hypocalcemia.

Maternal: DM, hyperparathyroidism; Perinatal: prematurity, asphyxia, infections

Name causes of late hypocalcemia in neonates.

Hypoparathyroidism, hypomagnesemia, vitamin D deficiency

What are the signs and symptoms of neonatal hypocalcemia?

Jitteriness, high-pitched cry, laryngospasm, tetany, positive Chvostek/Trousseau, seizures, prolonged QTc

How is neonatal hypocalcemia treated?

Calcium supplementation, vitamin D, low phosphate formula, breastfeeding

What is neonatal sepsis?

Clinical syndrome of systemic illness accompanied by bacteremia in the 1st month of life

How are neonatal infections classified by timing?

Congenital, perinatal, early onset, late onset, very late onset

Which neonates have a higher incidence of sepsis?

Term male infants; low birth weight infants; preterm infants with maternal chorioamnionitis, congenital immune defects, gene mutations affecting innate immunity, galactosemia, or malformations

What are congenital infections?

Infections acquired in utero, usually viral or non-bacterial, often associated with congenital malformations or TORCH infections

What defines perinatal infections?

Infections acquired around delivery, up to the 1st week of life, can be bacterial or viral

What is early onset sepsis (EOS)?

Infection in the first 7 days of life, usually from perinatal acquisition, vertical transmission from mother

What are common causative agents of EOS?

Group B Streptococcus (GBS), E. coli, coagulase-negative Staphylococcus, Haemophilus influenzae, Listeria monocytogenes

Which maternal factors increase risk of neonatal sepsis?

Chorioamnionitis, GBS colonization, preterm delivery (

What is late onset sepsis (LOS)?

Infection between 7–30 days of life, usually acquired postnatally from environment or invasive devices

What are common LOS pathogens?

Coagulase-negative Staphylococcus (CONS), Staphylococcus aureus, Pseudomonas species

Why are preterm neonates more susceptible to sepsis?

Immature epithelial barrier, low IgG, incompetent opsonization/complement activation, need for invasive devices

Name 3 defense mechanisms of the innate immune system in neonates.

(1) Physical barrier (skin/mucosa), (2) Cellular component, (3) Humoral response

When does maternal IgG transfer start and peak?

Starts around 34 weeks gestation, maximal transfer at 36 weeks

What are common clinical signs of neonatal sepsis?

Respiratory distress, apnea, hypoxia, temperature instability, lethargy, feeding intolerance, jaundice, pallor, hypotension (late sign)

What is the first step in managing suspected neonatal sepsis?

Start empiric antibiotics immediately, even without lab confirmation

What antibiotics are typically used for early onset sepsis?

IV ampicillin + aminoglycoside (covers GBS, E. coli, Listeria)

What antibiotics are used for late onset sepsis?

Vancomycin + aminoglycoside or cephalosporin + aminoglycoside, depending on nosocomial pathogens

What is the mortality rate of EOS and LOS?

EOS: 5–10%, LOS: 2–6%; higher in preterm or low birth weight infants

Name 3 complications of neonatal sepsis.

Chronic lung disease, neurodevelopmental impairment (hearing/vision), multiorgan failure

What preventive measure reduces vertical transmission of GBS?

Intrapartum Antibiotic Prophylaxis (IAP) at least 4 hours prior to delivery

What congenital infections are included in TORCHES CLAP?

Toxoplasmosis, Rubella, CMV, HSV, VZV, Congenital syphilis, Parvovirus, HIV, Hepatitis B, Neisseria gonorrhoeae, Chlamydia, Mycobacterium tuberculosis

Which congenital infections are most common?

CMV, Rubella, Toxoplasmosis

What is dysmorphology?

The study of differences in human form and the mechanisms that cause them

What percentage of newborns have a recognizable birth defect?

Approximately 2.5% (1 in 40)

How many newborns with malformations have a single vs. multiple anomaly?

About half have a single malformation, the other half have multiple malformations

What proportion of infant deaths is caused by congenital abnormalities?

20-30% of infant deaths and 30-50% of deaths after the neonatal period

What are the five categories of congenital malformations?

Single gene mutations (6%), Chromosomal disorders (7.5%), Multifactorial inherited conditions (20%), Disorders with unusual inheritance patterns (2-3%), Conditions caused by teratogens (6%)

What is a dysmorphic feature?

A difference in the body’s structure, which can be normal or related to a congenital disorder/syndrome or birth defect