Neonatology Practice Questions

Q: What is the most common obstetrics nerve palsy observed in newborns?

Facial nerve. **Explanation:** The **Facial nerve (CN VII)** is the most common birth-related nerve palsy. This injury typically occurs due to compression of the nerve as it exits the stylomastoid foramen. The primary risk factors include **forceps-assisted delivery** (where the forceps blade exerts direct pressure on the nerve) and prolonged labor where the nerve is compressed against the maternal sacral promontory. Clinically, it presents as loss of the nasolabial fold, inability to close the eye, and the mouth drooping toward the unaffected side when the infant cries. Most cases are neuropraxic and resolve spontaneously within weeks. **Analysis of Incorrect Options:** * **Common Peroneal Nerve (C):** While this is the most common lower extremity palsy in adults (due to its superficial position at the fibular head), it is rare in neonates. It may occur due to intrauterine malposition or umbilical artery catheterization complications, but it is far less frequent than facial nerve injury. * **Tibial and Sural Nerves (A & B):** These nerves are deeply seated or located in protected areas. Isolated birth injuries to these nerves are extremely rare and are not characteristic of obstetric trauma. **High-Yield Clinical Pearls for NEET-PG:** * **Most common peripheral nerve injury:** Brachial plexus injury (Erb’s palsy is the most frequent subtype). * **Most common cranial nerve injury:** Facial nerve (CN VII). * **Differential Diagnosis:** Always distinguish traumatic facial palsy from **Möbius syndrome** (congenital aplasia of the 6th and 7th cranial nerve nuclei), which presents with bilateral involvement and inability to abduct the eyes. * **Management:** Most traumatic facial palsies require only supportive care (e.g., artificial tears to prevent corneal ulceration).

Q: Which of the following is a risk factor for retinopathy of prematurity (ROP)?

Prematurity (born at 28 weeks gestation). **Explanation:** **Retinopathy of Prematurity (ROP)** is a vasoproliferative disorder caused by the abnormal development of retinal blood vessels in preterm infants. **Why Option A is Correct:** The primary risk factors for ROP are **low gestational age** and **low birth weight**. Normal retinal vascularization begins at 16 weeks of gestation and is completed peripherally by 40 weeks (term). When an infant is born at **28 weeks**, the retina is incompletely vascularized. The transition from the relatively hypoxic intrauterine environment to extrauterine hyperoxia (often exacerbated by supplemental oxygen) causes initial vasoconstriction and vessel obliteration, followed by the release of Vascular Endothelial Growth Factor (VEGF), leading to pathological neovascularization. **Analysis of Incorrect Options:** * **Option B (RDS):** While RDS often necessitates oxygen therapy (a major risk factor), RDS itself is a pulmonary condition. The underlying prematurity is the definitive risk factor for the retinal pathology. * **Option C (Birth weight 2.3 kg):** Screening for ROP is typically indicated for infants with a birth weight **≤1500g** or gestational age **≤32 weeks**. A weight of 2.3 kg is significantly above the high-risk threshold. * **Option D (Neonatal Jaundice):** There is no established direct causal link between hyperbilirubinemia and the pathogenesis of ROP. **High-Yield Clinical Pearls for NEET-PG:** * **Screening Criteria (India/RBSK):** All infants <32 weeks OR <1500g; also infants 32–35 weeks/1500–2000g with an unstable clinical course. * **Timing of First Screen:** Usually at **4 weeks (30 days)** of life or 31 weeks post-menstrual age (whichever is later). * **Zone of Involvement:** Zone 1 (centered on the optic nerve) is the most critical/severe. * **Plus Disease:** Characterized by venous dilation and arterial tortuosity in the posterior pole; it indicates active, severe ROP.

Q: What is the most common cause of an abdominal mass in neonates?

Multicystic dysplastic kidney. In neonatology, abdominal masses are frequently encountered, and the vast majority (approximately 55-60%) are of **renal origin**. **Why Multicystic Dysplastic Kidney (MCDK) is correct:** MCDK is the most common cause of a palpable abdominal mass in a newborn. It results from abnormal metanephric differentiation, leading to a non-functioning kidney replaced by multiple non-communicating cysts. While Hydronephrosis (often due to UPJ obstruction) is the most common cause of neonatal *neonatal renal enlargement* overall, MCDK is the most common *cystic* renal mass identified clinically. **Analysis of Incorrect Options:** * **A. Neuroblastoma:** This is the most common *malignant* abdominal tumor in neonates, but it is significantly less common than benign renal anomalies. * **C. Polycystic Kidney:** Autosomal Recessive Polycystic Kidney Disease (ARPKD) typically presents with bilateral, smooth, "giant" flank masses and is less common than the sporadic, often unilateral MCDK. * **D. Umbilical Hernia:** This is a defect in the abdominal wall, not an intra-abdominal mass. **High-Yield Clinical Pearls for NEET-PG:** * **Most common cause of neonatal abdominal mass:** Renal anomalies (MCDK > Hydronephrosis). * **Most common neonatal renal malignancy:** Congenital Mesoblastic Nephroma (not Wilms tumor, which peaks at 3–4 years). * **Most common neonatal adrenal mass:** Adrenal Hemorrhage (often presents with jaundice and a drop in hematocrit). * **Initial Investigation:** Ultrasonography is the gold standard first-line investigation for any suspected neonatal abdominal mass.

Q: A 6-week-old infant is admitted to the hospital with jaundice. Out-patient blood work demonstrated a total bilirubin of 12 mg/dL with a direct portion of 3.5 mg/dL. Which of the following disorders is most likely to be responsible?

Choledochal cyst. **Explanation** The core of this question lies in distinguishing between **unconjugated (indirect)** and **conjugated (direct) hyperbilirubinemia**. 1. **Why Choledochal Cyst is Correct:** The infant has a total bilirubin of 12 mg/dL and a direct bilirubin of 3.5 mg/dL. According to clinical guidelines, direct hyperbilirubinemia (cholestasis) is defined as a direct bilirubin >1.0 mg/dL if the total is 20% of the total** if the total is >5 mg/dL. Here, 3.5 mg/dL is ~29% of the total, confirming cholestasis. A **choledochal cyst** is a structural cause of extrahepatic biliary obstruction leading to conjugated jaundice, typically presenting in early infancy with jaundice, an abdominal mass, or clay-colored stools. 2. **Why Incorrect Options are Wrong:** * **ABO and Rh Incompatibility:** These are causes of **hemolytic jaundice**, which results in the overproduction of **unconjugated** bilirubin. Furthermore, Rh/ABO incompatibility typically presents in the first 24–48 hours of life, not at 6 weeks. * **Gilbert Disease:** This is a benign genetic condition characterized by reduced activity of the enzyme UDP-glucuronosyltransferase. It causes mild, intermittent **unconjugated** hyperbilirubinemia, usually triggered by stress or fasting, and rarely presents in the neonatal period. **NEET-PG High-Yield Pearls:** * **Conjugated Jaundice is always pathologic:** Any neonate with jaundice at 2 weeks of age or older must be screened for cholestasis. * **Biliary Atresia:** The most common cause of neonatal cholestasis; must be ruled out alongside choledochal cysts using ultrasound and HIDA scans. * **Kasai Procedure:** Best outcomes for biliary atresia occur when surgery is performed before 60 days of life. * **Stool Color:** Always ask about "acholic" (pale/clay-colored) stools in cases of direct hyperbilirubinemia.

Q: What device is used to prevent hypothermia in a preterm neonate?

Incubator. **Explanation:** The primary goal in managing a preterm neonate is maintaining a **Neutral Thermal Environment (NTE)**, where oxygen consumption and metabolic rate are minimal. **Why the Incubator is correct:** An **Incubator** is the preferred device for long-term thermoregulation in stable preterm neonates. It provides a closed environment that controls not only air temperature but also **humidity**. High humidity is crucial for preterms (especially <30 weeks) to reduce **transepidermal water loss (TEWL)** and prevent evaporative heat loss, which is their primary mode of cooling. **Analysis of Incorrect Options:** * **Radiant Warmer:** While excellent for resuscitation and procedures because it allows easy access to the baby, it is an open system. It increases insensible water loss and is generally used for short-term stabilization rather than long-term care of small preterms. * **Room Heater:** These are unsafe as they provide unregulated heat, increase the risk of fire/burns, and do not address the specific physiological needs (like humidity) of a neonate. * **Phototherapy Unit:** This is used specifically for treating neonatal hyperbilirubinemia (jaundice) by converting bilirubin into water-soluble isomers. While the lamps emit some heat, it is not a thermoregulation device. **High-Yield Clinical Pearls for NEET-PG:** * **Modes of Heat Loss:** Evaporation (most common in delivery room), Radiation (most common in nursery), Convection, and Conduction. * **Kangaroo Mother Care (KMC):** The most effective low-cost method for preventing hypothermia in stable LBW infants. * **Cold Stress:** Defined as a rectal temperature of 36.0°C–36.4°C. Neonates do not shiver; they rely on **Non-shivering Thermogenesis** via metabolism of **Brown Adipose Tissue**. * **VLBW/ELBW:** For extremely preterm babies, plastic wraps or "polyethylene bags" are used immediately after birth to prevent evaporative heat loss.

Question 1

What is the most common obstetrics nerve palsy observed in newborns?

Accepted Answer

Facial nerve

Answer

Sural nerve

Answer

Tibial nerve

Answer

Common peroneal nerve

Question 2

Which of the following scoring systems is used to assess respiratory distress in neonates?

Accepted Answer

Silverman-Anderson score

Answer

CRIB score

Answer

APGAR score

Answer

SNAP score

Question 3

Which of the following is a risk factor for retinopathy of prematurity (ROP)?

Accepted Answer

Prematurity (born at 28 weeks gestation)

Answer

Respiratory distress syndrome

Answer

Birth weight of 2.3 kg

Answer

Neonatal jaundice

Question 4

What is the most common cause of an abdominal mass in neonates?

Accepted Answer

Multicystic dysplastic kidney

Answer

Neuroblastoma

Answer

Polycystic kidney

Answer

Umbilical hernia

Question 5

All the following mechanisms contribute to heat production in a neonate, EXCEPT:

Accepted Answer

Shivering

Answer

Breakdown of brown fat with adrenaline secretion

Answer

Universal flexion similar to a fetus

Answer

Cutaneous vasoconstriction

Question 6

A 6-week-old infant is admitted to the hospital with jaundice. Out-patient blood work demonstrated a total bilirubin of 12 mg/dL with a direct portion of 3.5 mg/dL. Which of the following disorders is most likely to be responsible?

Accepted Answer

Choledochal cyst

Answer

ABO incompatibility

Answer

Rh incompatibility

Answer

Gilbert disease

Question 7

What is true about neonatal sepsis?

Accepted Answer

Late sepsis is due to organisms in the maternal genital tract.

Answer

Early sepsis is due to organisms in the maternal genital tract.

Answer

Environmental factors cause late sepsis.

Answer

Environmental factors cause early sepsis.

Question 8

Unconjugated hyperbilirubinemia in neonates is seen in all of the following conditions except?

Accepted Answer

Dubin-Johnson syndrome

Answer

Physiological jaundice

Answer

Hypothyroidism

Answer

Hemolytic anemia

Question 9

What device is used to prevent hypothermia in a preterm neonate?

Accepted Answer

Incubator

Answer

Radiant warmer

Answer

Room heater

Answer

Phototherapy unit

Question 10

Which of the following best describes Level 3 newborn care?

Accepted Answer

Care for neonates with less than 32 weeks gestation and less than 1500 gm, and those with critical illnesses.

Answer

Includes the full range of advanced subspecialities, including cardiac surgery.

Answer

Care for neonates with more than 32 weeks gestation and 500 gm.

Answer

Ability to provide CPAP and ventilation for brief periods.

Neonatology — MCQs

Neonatology — MCQs

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