Neonatology — MCQs

Neonatology Indian Medical PG Practice Questions and MCQs

Question 621: Which of the following substances is toxic to neurons?

A. Unconjugated bilirubin (Correct Answer)
B. Bile salt
C. Haemoglobin
D. Melanin

Explanation: ### Explanation **Correct Answer: A. Unconjugated bilirubin** **Medical Concept:** Unconjugated bilirubin (UCB) is the correct answer because it is **lipid-soluble (lipophilic)** and non-polar. Unlike conjugated bilirubin, UCB can cross the blood-brain barrier (BBB) when its concentration exceeds the binding capacity of albumin. Once in the brain, it has a high affinity for lipid-rich neuronal tissue, particularly in the **basal ganglia** (subthalamic nucleus and globus pallidus) and brainstem nuclei. It causes neurotoxicity by inhibiting mitochondrial enzymes, interfering with DNA synthesis, and inducing apoptosis, leading to **Kernicterus** (Chronic Bilirubin Encephalopathy). **Why Incorrect Options are Wrong:** * **B. Bile salts:** These are detergents synthesized in the liver to aid lipid digestion. While they can cause pruritus (itching) in obstructive jaundice, they are not neurotoxic. * **C. Haemoglobin:** While the breakdown of hemoglobin produces bilirubin, the hemoglobin molecule itself is not neurotoxic. It is usually contained within RBCs or bound to haptoglobin in the plasma. * **D. Melanin:** This is a natural pigment produced by melanocytes in the skin and brain (substantia nigra). It is protective against UV radiation and is not a neurotoxin. **NEET-PG High-Yield Pearls:** * **Kernicterus Site:** The most common site affected is the **Globus Pallidus**. * **Albumin Binding:** Only "Free" UCB (not bound to albumin) crosses the BBB. Conditions like acidosis, prematurity, and drugs (e.g., sulfonamides) displace bilirubin from albumin, increasing toxicity risk. * **Bilirubin Levels:** In healthy term neonates, neurotoxicity usually occurs when Total Serum Bilirubin (TSB) exceeds **20–25 mg/dL**. * **Clinical Sign:** The earliest sign of acute bilirubin encephalopathy is often poor feeding and **lethargy**, progressing to **opisthotonus** (arching of the back).

Question 622: Which of the following diseases can lead to opisthotonus?

A. Tetany
B. Kernicterus (Correct Answer)
C. Measles
D. Pertussis

Explanation: **Explanation:** **Kernicterus** (Bilirubin-induced neurologic dysfunction) is the correct answer. It occurs when unconjugated bilirubin crosses the blood-brain barrier and deposits in the **basal ganglia** and brainstem nuclei. **Opisthotonus**—a state of severe hyperextension where the head, neck, and spinal column enter a bridge-like arching position—is a hallmark clinical sign of **Acute Bilirubin Encephalopathy (Phase 2)**. It results from extrapyramidal involvement and intense muscle spasticity. **Analysis of Incorrect Options:** * **Tetany (A):** Characterized by increased neuromuscular irritability due to hypocalcemia. Clinical features include carpopedal spasm, laryngospasm, and seizures, but not typically opisthotonus. * **Measles (C):** A viral prodrome followed by a maculopapular rash and Koplik spots. While it can cause encephalitis as a complication, opisthotonus is not a classic or defining feature. * **Pertussis (D):** Known as "whooping cough," it presents with paroxysmal cough and inspiratory whoop. Neurological symptoms (pertussis encephalopathy) are rare and usually secondary to hypoxia or hemorrhage, not primary opisthotonus. **High-Yield Clinical Pearls for NEET-PG:** * **Target Site:** The **Globus Pallidus** is the most common site of bilirubin deposition in Kernicterus. * **Clinical Triad of Chronic Kernicterus:** Choreoathetoid cerebral palsy, sensorineural hearing loss (SNHL), and upward gaze palsy. * **Differential Diagnosis for Opisthotonus:** Tetanus (neonatal and adult), Kernicterus, Meningitis, and Phenothiazine toxicity (extrapyramidal reaction). * **MRI Finding:** High-intensity signals in the globus pallidus on T2-weighted images.

Question 623: A newborn with an APGAR score of 2 at 1 minute and 6 at 5 minutes presents with respiratory distress and mediastinal shift. What is the most likely diagnosis?

A. Congenital adenomatoid lung disease
B. Pneumothorax
C. Diaphragmatic hernia
D. All of these (Correct Answer)

Explanation: **Explanation:** The correct answer is **D. All of these**. The clinical presentation of a newborn with low APGAR scores, respiratory distress, and a **mediastinal shift** indicates a space-occupying lesion or pressure imbalance within the thoracic cavity that is displacing the heart and trachea to the contralateral side. **1. Why "All of these" is correct:** * **Congenital Diaphragmatic Hernia (CDH):** This is the most classic cause. Abdominal contents herniate into the chest (usually the left side), compressing the lungs and shifting the mediastinum to the opposite side. It presents with a scaphoid abdomen and immediate respiratory distress. * **Pneumothorax:** In neonates (especially those requiring resuscitation or having meconium aspiration), air can leak into the pleural space. A tension pneumothorax creates positive pressure that pushes the mediastinum away from the affected side. * **Congenital Pulmonary Airway Malformation (CPAM/CCAM):** This is a cystic adenomatoid proliferation of lung tissue. Large cysts can cause significant mass effect, leading to lung hypoplasia and mediastinal shift. **2. Clinical Pearls for NEET-PG:** * **Immediate Management of CDH:** Avoid bag-and-mask ventilation (as it distends the bowel in the chest, worsening compression); instead, perform **immediate endotracheal intubation**. * **Diagnosis:** A chest X-ray is the gold standard for differentiating these conditions. CDH shows bowel loops in the thorax; Pneumothorax shows a hyperlucent area without lung markings; CPAM shows multi-cystic lesions. * **Mediastinal Shift:** Always look for this sign in "Respiratory Distress" questions. If the shift is *toward* the lesion, think of collapse/agenesis; if the shift is *away* from the lesion, think of CDH, pneumothorax, or cysts.

Question 624: A newborn has a heart rate of 80 bpm and gasping respirations. What is your next immediate step?

A. Positive pressure ventilation with room air. (Correct Answer)
B. Intubate the newborn.
C. Positive pressure ventilation with 50% oxygen.
D. Continuous positive airway pressure with 100% oxygen.

Explanation: ### Explanation The management of a newborn at birth follows the **NRP (Neonatal Resuscitation Program) 8th Edition guidelines**. The primary goal in neonatal resuscitation is to establish effective ventilation, as most neonatal depression is due to respiratory failure rather than primary cardiac issues. **Why Option A is Correct:** The key triggers for starting **Positive Pressure Ventilation (PPV)** are: 1. Apnea or gasping respirations. 2. Heart rate (HR) < 100 bpm. In this scenario, the newborn has both gasping respirations and a HR of 80 bpm, making PPV the immediate priority. For term and late-preterm infants (≥35 weeks), resuscitation should always be initiated with **room air (21% oxygen)** to prevent oxidative stress and damage to the developing brain and lungs. **Why Other Options are Incorrect:** * **Option B:** Intubation is usually reserved for cases where PPV is ineffective, prolonged, or if chest compressions are required. It is not the first step. * **Option C & D:** High concentrations of oxygen (50% or 100%) are contraindicated for initial resuscitation in term infants. Excessive oxygen causes "oxygen toxicity" due to free radical formation. Oxygen concentration is only titrated upward based on pre-ductal SpO2 targets using a blender. CPAP is used for babies with labored breathing or persistent cyanosis who have a HR > 100 bpm, not for those with a HR < 100 bpm. **Clinical Pearls for NEET-PG:** * **Golden Minute:** The first 60 seconds of life are dedicated to completing the initial steps and starting PPV if indicated. * **Initial Oxygen Concentration:** * ≥35 weeks gestation: 21% O2 (Room air). * <35 weeks gestation: 21–30% O2. * **MR. SOPA:** The mnemonic used to troubleshoot ineffective PPV (Mask adjustment, Reposition airway, Suction, Open mouth, Pressure increase, Alternative airway). * **Chest Compressions:** Only initiated if HR remains < 60 bpm despite 30 seconds of effective PPV.

Question 625: What is the minimum and maximum score of the Expanded New Ballard Score?

A. -15 and 40
B. 20 and 44
C. -20 and 44
D. -10 and 50 (Correct Answer)

Explanation: **Explanation:** The **New Ballard Score (NBS)** is a clinical tool used to estimate gestational age in neonates by assessing physical and neuromuscular maturity. The "Expanded" version was specifically designed to include extremely premature infants (born as early as 20 weeks). **1. Why the Correct Answer is D (-10 and 50):** The Expanded New Ballard Score assesses **6 Neuromuscular** and **6 Physical** criteria. Each criterion is scored on a scale from -1 to 5 (some physical criteria start at -2). * **Minimum Score:** The lowest possible score for each of the 12 categories is either -1 or -2. When totaled, the minimum cumulative score is **-10**, which corresponds to **20 weeks** of gestation. * **Maximum Score:** The highest possible score for each category is 5 (for post-mature features). The maximum cumulative score is **50**, which corresponds to **44 weeks** of gestation. **2. Analysis of Incorrect Options:** * **Option A (-15 and 40):** Incorrect range; the scale does not go as low as -15, and 40 only represents 40 weeks of gestation. * **Option B (20 and 44):** These numbers represent the gestational age range (20 to 44 weeks) that the score covers, not the numerical score itself. * **Option C (-20 and 44):** Incorrect; -20 is not a possible score, and 44 is the gestational age limit, not the maximum score. **Clinical Pearls for NEET-PG:** * **Timing:** For maximum accuracy, the assessment should be performed within **24 hours** of birth. If the infant is <26 weeks, it should be done within the first 12 hours. * **Components:** Remember the "6+6" rule (6 Neuromuscular + 6 Physical signs). * **Neuromuscular signs include:** Posture, Square window, Arm recoil, Popliteal angle, Scarf sign, and Heel to ear. * **Physical signs include:** Skin, Lanugo, Plantar surface, Breast, Eye/Ear, and Genitals.

Question 626: A term neonate, delivered by C-section, presents with respiratory distress immediately after birth. X-ray shows perihilar streaking, and the distress subsides after 48-72 hours. What is the diagnosis?

A. Neonatal apnea
B. Meconium aspiration syndrome
C. ARDS
D. Transient tachypnea of the newborn (Correct Answer)

Explanation: **Explanation:** **Transient Tachypnea of the Newborn (TTN)**, also known as "Wet Lung Disease," is the most likely diagnosis. The underlying pathophysiology is the **delayed clearance of fetal lung fluid** by the pulmonary lymphatic system. 1. **Why Option D is correct:** TTN characteristically occurs in **term neonates** delivered via **elective C-section** (missing the "thoracic squeeze" of vaginal delivery) or precipitous labor. The classic X-ray findings include **perihilar streaking** (prominent pulmonary vascular markings) and fluid in the interlobar fissures. Clinically, the distress is self-limiting and typically resolves within **48–72 hours** as the fluid is absorbed. 2. **Why other options are incorrect:** * **Neonatal Apnea:** Refers to a cessation of breathing for >20 seconds; it is a disorder of respiratory control, not a parenchymal lung issue presenting with tachypnea. * **Meconium Aspiration Syndrome (MAS):** Occurs in post-term infants with a history of meconium-stained liquor. X-ray shows "patchy opacities" and hyperinflation, not simple perihilar streaking. * **ARDS (or RDS/HMD):** Primarily affects **preterm** infants due to surfactant deficiency. X-ray shows a "ground-glass" appearance and air bronchograms. **Clinical Pearls for NEET-PG:** * **Risk Factors:** Elective C-section, maternal asthma, and maternal diabetes. * **X-ray Buzzwords:** Perihilar streaking, "Sunburst" appearance, fluid in fissures, and mild cardiomegaly. * **Management:** Supportive care (oxygen via hood/CPAP). It is a diagnosis of exclusion. * **Key differentiator:** If the distress lasts >72 hours, reconsider the diagnosis (e.g., pneumonia or congenital heart disease).

Question 627: What are the most common causes of perinatal mortality?

A. Birth injury
B. Intrauterine infection
C. Birth asphyxia (Correct Answer)
D. Low birth weight (LBW)

Explanation: **Explanation:** Perinatal mortality refers to fetal deaths after 28 weeks of gestation (stillbirths) plus early neonatal deaths (within the first 7 days of life). Understanding the leading causes is crucial for NEET-PG, as these statistics often appear in both Pediatrics and PSM. **Why Birth Asphyxia is the Correct Answer:** Birth asphyxia (hypoxic-ischemic insult) is the leading cause of perinatal mortality globally and in India. It occurs due to an impairment in gas exchange during the birthing process, leading to progressive hypoxemia and hypercapnia. It accounts for a significant portion of both late stillbirths and early neonatal deaths. While prematurity is the leading cause of *neonatal* mortality (0–28 days), birth asphyxia takes precedence in the *perinatal* period. **Analysis of Incorrect Options:** * **A. Birth Injury:** While significant in the past, improved obstetric techniques and the rise of C-sections have made fatal birth injuries (like intracranial hemorrhage from forceps) relatively rare. * **B. Intrauterine Infection:** Infections (TORCH, Chorioamnionitis) are important causes of fetal loss, but they are statistically less frequent than asphyxia-related events. * **D. Low Birth Weight (LBW):** LBW is a major *predisposing factor* or "underlying cause" for mortality, but it is generally categorized as a contributor to neonatal mortality rather than the primary cause of perinatal death in this specific comparison. **High-Yield Clinical Pearls for NEET-PG:** * **Leading cause of Neonatal Mortality (0-28 days):** Prematurity/Preterm birth complications. * **Leading cause of Infant Mortality (0-1 year):** Prematurity (followed by Sepsis/Pneumonia). * **Leading cause of Under-5 Mortality:** Pneumonia (Globally) / Prematurity (India). * **The "Golden Hour":** The first 60 minutes of postnatal life where timely resuscitation can prevent asphyxia-related mortality.

Question 628: A 32-week premature infant, weighing less than 1 kg and otherwise healthy, presents with jaundice and a serum bilirubin level of 5 mg%. What is the ideal management in this case?

A. Observation
B. Phototherapy (Correct Answer)
C. Medical management
D. Exchange transfusion

Explanation: **Explanation:** The management of neonatal jaundice in preterm infants depends on birth weight, gestational age, and clinical stability. In this case, the infant is **extremely low birth weight (ELBW <1000g)** and premature (32 weeks). **1. Why Phototherapy is Correct:** Preterm infants are at a significantly higher risk of bilirubin encephalopathy (Kernicterus) at much lower bilirubin levels than term infants due to an immature blood-brain barrier and lower serum albumin levels. For an infant weighing **<1000g**, the threshold to initiate phototherapy is very low—typically starting at **5 mg/dL** or even prophylactic phototherapy in some protocols. This "aggressive" approach prevents the bilirubin from reaching levels that would require invasive exchange transfusion. **2. Why Other Options are Incorrect:** * **Observation:** While 5 mg% is normal for a term baby, it is the treatment threshold for an ELBW infant. Delaying treatment risks neurotoxicity. * **Medical Management:** Drugs like Phenobarbitone (to induce glucuronosyltransferase) take 48–72 hours to work and are not indicated for acute management of neonatal jaundice. * **Exchange Transfusion:** This is a high-risk procedure reserved for cases where bilirubin levels are dangerously high (typically >10–15 mg/dL in this weight category) or when intensive phototherapy fails. **Clinical Pearls for NEET-PG:** * **Rule of Thumb for Preterms:** A common clinical guide for starting phototherapy in stable preterms is **1% of birth weight** (e.g., 5 mg/dL for 500g, 10 mg/dL for 1000g). However, for ELBW infants (<1kg), many guidelines mandate starting at 5 mg/dL regardless. * **Maximum Bilirubin:** In term infants, jaundice is "pathological" if it appears in the first 24 hours, rises >5 mg/dL/day, or exceeds 15 mg/dL. * **Most common cause** of jaundice requiring exchange transfusion is Rh isoimmunization.

Question 629: What differentiates secondary apnea from primary apnea in a newborn?

A. Simple stimulation reverses it.
B. Accompanied by loss of neuromuscular tone.
C. Will spontaneously resume respiratory efforts.
D. Clinically, primary and secondary apnea are indistinguishable. (Correct Answer)

Explanation: ### Explanation In neonatal resuscitation, understanding the progression of respiratory failure is crucial. When a newborn experiences hypoxia, they undergo a predictable sequence: initial rapid breathing followed by **Primary Apnea**, then gasping, and finally **Secondary (Terminal) Apnea**. **Why Option D is correct:** Clinically, when a clinician first encounters a non-breathing neonate, it is **impossible to distinguish** between primary and secondary apnea by physical examination alone. Both present with a lack of respiratory effort, cyanosis, and varying degrees of bradycardia. The differentiation is made retrospectively based on the **response to stimulation**. **Analysis of Incorrect Options:** * **Option A:** Simple stimulation (flicking the soles or rubbing the back) only reverses **Primary Apnea**. Secondary apnea will not respond to tactile stimulation. * **Option B:** While neuromuscular tone decreases as hypoxia progresses, both stages can present with hypotonia. It is not a definitive clinical differentiator at the bedside. * **Option C:** Primary apnea may spontaneously resolve if the insult is removed, but **Secondary Apnea** will never resume spontaneously; it requires Positive Pressure Ventilation (PPV) to restore breathing. **High-Yield Clinical Pearls for NEET-PG:** * **The Golden Rule:** If a newborn does not breathe immediately after stimulation, assume they are in **Secondary Apnea** and initiate PPV immediately. * **Heart Rate:** In primary apnea, the heart rate is usually maintained or slightly decreased; in secondary apnea, the heart rate falls significantly. * **Sequence of Events:** Rapid breathing $\rightarrow$ Primary Apnea $\rightarrow$ Gasping $\rightarrow$ Secondary Apnea $\rightarrow$ Death. * **Recovery:** During recovery from secondary apnea, the sequence is reversed (except for the initial rapid breathing): the baby starts gasping first before regular rhythmic respirations return.

Question 630: Which of the following are associated with neonatal lupus?

A. Heart block
B. Thrombocytopenia
C. Cutaneous lesion
D. All of the above (Correct Answer)

Explanation: **Explanation:** Neonatal Lupus Erythematosus (NLE) is a rare acquired autoimmune disorder caused by the transplacental passage of maternal **anti-Ro (SS-A)** and **anti-La (SS-B)** antibodies. It is not true systemic lupus; rather, it is a form of passive immunity where maternal antibodies damage fetal tissues. **Why "All of the above" is correct:** * **Heart Block (Option A):** This is the most serious complication. It typically manifests as a **permanent** third-degree (complete) congenital heart block due to antibody-mediated fibrosis of the AV node. It is often detected in utero (fetal bradycardia). * **Thrombocytopenia (Option B):** Hematological abnormalities are common but usually **transient**. These include thrombocytopenia, neutropenia, or anemia, resolving as maternal antibodies clear the infant’s system (usually by 6 months). * **Cutaneous Lesions (Option C):** These are classic **transient** erythematous, annular (ring-shaped) scaly plaques, often appearing in the periorbital area ("raccoon eyes" or "owl's eye" appearance). They typically appear after UV light exposure and resolve without scarring. **Clinical Pearls for NEET-PG:** 1. **Reversibility:** Unlike the permanent cardiac damage, the skin, liver, and hematological manifestations are **transient** and disappear as maternal IgG is metabolized. 2. **Maternal Status:** The mother may be asymptomatic at the time of delivery or have a diagnosed connective tissue disease (SLE or Sjögren’s syndrome). 3. **Treatment:** Permanent heart block often requires a **pacemaker**. Cutaneous lesions require sun protection. 4. **Key Antibodies:** Always associate NLE with **Anti-Ro/SSA** (most specific) and **Anti-La/SSB**.

Practice by Chapter

Neonatal Resuscitation

Practice Questions

Care of the Normal Newborn

Practice Questions

Prematurity and Low Birth Weight

Practice Questions

Respiratory Distress Syndrome

Practice Questions

Neonatal Jaundice

Practice Questions

Neonatal Sepsis

Practice Questions

Necrotizing Enterocolitis

Practice Questions

Intraventricular Hemorrhage

Practice Questions

Persistent Pulmonary Hypertension

Practice Questions

Perinatal Asphyxia

Practice Questions

Neonatal Seizures

Practice Questions

Congenital Anomalies

Practice Questions

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