Neonatology — MCQs
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Dried blood drops from an infant can be used to screen for which of the following?
A mother reports that her 2-week-old infant sleeps most of the day and needs to be awakened every 4 hours for feeding, taking only one ounce of formula at a time. She is also concerned about the infant's persistently hard, pellet-like stools. Examination reveals an infant with normal weight and length, but with an enlarged head, a heart rate of 75 beats per minute, a temperature of 35°C (95°F), persistent jaundice, large anterior and posterior fontanelles, a distended abdomen, and an umbilical hernia. This clinical presentation is likely a result of which of the following?
In Rh isoimmunization, exchange transfusion is indicated in all of the following situations EXCEPT:
A neonate presents with a warm abdomen but cold extremities. What is the likely condition?
Respiratory distress syndrome (RDS) in a neonate is primarily due to deficiency of which substance?
What is the common cause of neonatal hypoglycemia?
A newborn has a fever of 103°F. Blood culture grows gram-positive cocci in chains. This is most likely to be which of the following?
A neonate delivered at 38 weeks of gestation with a birth weight of 2.2 kg develops intolerance to feeds and abdominal distension on the second day of life. Physical examination is unremarkable. Sepsis screen is negative. PCV is observed to be 72%. What is the best management option?
Hypoglycemia in a newborn is seen in which of the following conditions?
Macrosomia is seen in all of the following conditions EXCEPT:
Neonatology Indian Medical PG Practice Questions and MCQs
Question 11: Dried blood drops from an infant can be used to screen for which of the following?
- A. Blood sugar levels
- B. Inborn errors of metabolism (Correct Answer)
- C. Hepatitis infection
- D. Congenital cataracts
Explanation: **Explanation:** The correct answer is **Inborn Errors of Metabolism (IEM)**. This screening method is known as the **Guthrie Test** or **Newborn Screening (NBS)** using **Dried Blood Spots (DBS)**. 1. **Why it is correct:** Dried blood spots are collected by pricking the infant's heel (Heel-prick test) and dropping the blood onto specialized filter paper (Whatman 903). This method is ideal for screening IEMs because the samples are stable, easy to transport, and can be analyzed using **Tandem Mass Spectrometry (TMS)**. Common conditions screened include Phenylketonuria (PKU), Congenital Hypothyroidism, Galactosemia, and G6PD deficiency. 2. **Why other options are incorrect:** * **Blood sugar levels:** These require immediate analysis of fresh whole blood (usually via glucometer or venous sample) to manage acute hypoglycemia; dried spots are not suitable for real-time monitoring. * **Hepatitis infection:** Screening for Hepatitis B or C in neonates typically involves serological markers (HBsAg) or PCR from fresh serum/plasma, not routine dried blood spots. * **Congenital cataracts:** This is a clinical diagnosis made via the **Red Reflex Test** (Bruckner test) using an ophthalmoscope, not a laboratory blood test. **High-Yield Clinical Pearls for NEET-PG:** * **Timing:** NBS should ideally be performed **48–72 hours after birth** to ensure the infant has ingested sufficient protein (for PKU) and to avoid the physiological TSH surge. * **Most common IEM in India:** Congenital Hypothyroidism (CH) followed by G6PD deficiency. * **The "Guthrie Test"** specifically refers to the original bacterial inhibition assay for Phenylketonuria. * **Storage:** DBS samples can be stored at room temperature for long periods, making them excellent for large-scale epidemiological studies.
Question 12: A mother reports that her 2-week-old infant sleeps most of the day and needs to be awakened every 4 hours for feeding, taking only one ounce of formula at a time. She is also concerned about the infant's persistently hard, pellet-like stools. Examination reveals an infant with normal weight and length, but with an enlarged head, a heart rate of 75 beats per minute, a temperature of 35°C (95°F), persistent jaundice, large anterior and posterior fontanelles, a distended abdomen, and an umbilical hernia. This clinical presentation is likely a result of which of the following?
- A. Congenital hypothyroidism (Correct Answer)
- B. Congenital megacolon (Hirschsprung disease)
- C. Sepsis
- D. Infantile botulism
Explanation: ### Explanation **Correct Answer: A. Congenital Hypothyroidism** This infant presents with the classic "quiet baby" syndrome of **Congenital Hypothyroidism (CH)**. Thyroid hormones are essential for metabolic processes and neurological development. A deficiency leads to a generalized slowing of body functions, manifesting as: * **Metabolic slowing:** Hypothermia (35°C), bradycardia (75 bpm), and lethargy (sleeping most of the day). * **Gastrointestinal:** Decreased motility leads to constipation (hard, pellet-like stools), poor feeding, and abdominal distension. * **Structural signs:** Large anterior and posterior fontanelles (delayed bone age), umbilical hernia, and macroglossia (often causing feeding issues). * **Jaundice:** Prolonged unconjugated hyperbilirubinemia due to delayed glucuronyl transferase activity. **Why other options are incorrect:** * **B. Hirschsprung Disease:** While it causes constipation, abdominal distension, and potentially an umbilical hernia, it does **not** explain the bradycardia, hypothermia, large fontanelles, or prolonged jaundice. * **C. Sepsis:** Can cause lethargy, poor feeding, and temperature instability, but it is an acute presentation. It would not explain the large fontanelles or umbilical hernia. * **D. Infantile Botulism:** Presents with "floppy baby" syndrome (hypotonia) and constipation, but typically occurs in slightly older infants (after honey ingestion) and does not feature the structural/metabolic signs of CH. **NEET-PG High-Yield Pearls:** * **Most common cause:** Dysgenesis (Agenesis/Ectopy) of the thyroid gland. * **Most sensitive screening test:** Serum TSH (usually performed via heel prick on day 3–5). * **Clinical Clue:** A posterior fontanelle >0.5 cm in a term neonate is highly suggestive of CH. * **Treatment:** Levothyroxine (10–15 μg/kg/day). Early treatment (within 2 weeks) is critical to prevent permanent intellectual disability (Cretinism).
Question 13: In Rh isoimmunization, exchange transfusion is indicated in all of the following situations EXCEPT:
- A. Cord blood hemoglobin < 10 g/dL
- B. Cord bilirubin > 5 mg/dL
- C. Direct Coombs Test (DCT) positive with a history of a previously affected sibling
- D. Hydrops fetalis (Correct Answer)
Explanation: ### Explanation In Rh isoimmunization, the primary goal of **Exchange Transfusion (ET)** is to prevent bilirubin encephalopathy (kernicterus) by removing sensitized RBCs and circulating antibodies. **Why "Hydrops fetalis" is the correct answer (the exception):** Hydrops fetalis is a state of severe decompensated heart failure and anasarca. While these infants are severely affected by Rh isoimmunization, they are **hemodynamically unstable**. Performing a standard exchange transfusion immediately can be fatal due to volume overload or cardiac arrest. The immediate management for a hydropic neonate is **resuscitation and stabilization** (e.g., correction of hypoxia, paracentesis for respiratory distress, or a small-volume "partial" exchange transfusion with packed RBCs to correct anemia) rather than a formal double-volume exchange transfusion. **Analysis of Incorrect Options (Indications for ET):** * **Cord Hemoglobin < 10 g/dL:** This indicates severe fetal anemia, necessitating immediate replacement of RBCs to improve oxygen-carrying capacity. * **Cord Bilirubin > 5 mg/dL:** High cord bilirubin reflects rapid hemolysis occurring in utero, signaling a high risk for rapid post-natal jaundice. * **DCT positive with a history of a previously affected sibling:** A positive Direct Coombs Test combined with a significant family history indicates a high likelihood of aggressive hemolysis, often serving as an early indication for intervention. **High-Yield Pearls for NEET-PG:** * **Double Volume Exchange Transfusion (DVET):** Uses 160 ml/kg of blood; removes 85% of sensitized RBCs and 50% of bilirubin. * **Rate of Rise (ROR):** If serum bilirubin rises >0.5 mg/dL/hr despite intensive phototherapy, ET is indicated. * **Blood used for Rh isoimmunization:** O-negative (Rh-negative) blood cross-matched with the mother's serum. * **Most common cause of Hydrops Fetalis:** Currently, non-immune causes (e.g., chromosomal anomalies, parvovirus B19) are more common than Rh isoimmunization due to Anti-D prophylaxis.
Question 14: A neonate presents with a warm abdomen but cold extremities. What is the likely condition?
- A. Normal body temperature
- B. Severe hypothermia
- C. Cold stress (Correct Answer)
- D. Shock
Explanation: **Explanation:** The clinical presentation of a **warm abdomen with cold extremities** is the hallmark sign of **Cold Stress** (Mild Hypothermia) in a neonate. **1. Why Cold Stress is correct:** In neonates, the body’s initial physiological response to a drop in environmental temperature is peripheral vasoconstriction. This mechanism shunts blood away from the skin and extremities toward the vital organs in the core to maintain central temperature. Consequently, the extremities feel cold to the touch while the trunk (abdomen) remains warm. In neonatal thermoregulation, the core temperature (measured via the axilla or rectum) during cold stress typically ranges between **36.0°C to 36.4°C (96.8°F to 97.5°F)**. **2. Why the other options are incorrect:** * **Normal body temperature:** In a normothermic baby (36.5°C–37.5°C), both the trunk and the extremities should feel warm, indicating adequate peripheral perfusion. * **Severe hypothermia:** Defined as a core temperature **<32°C**. At this stage, the compensatory mechanisms have failed; both the abdomen and the extremities will be cold to the touch, often accompanied by bradycardia and central cyanosis. * **Shock:** While shock also presents with cold extremities due to poor perfusion, it is usually accompanied by other systemic signs like prolonged capillary refill time (>3 seconds), tachycardia, hypotension, and a weak pulse, rather than being a isolated finding of thermal imbalance. **NEET-PG High-Yield Pearls:** * **The "Touch Test":** It is a rapid clinical screening tool. If the feet are cold but the abdomen is warm, it is **Cold Stress**. If both are cold, it is **Moderate/Severe Hypothermia**. * **Brown Fat Metabolism:** Neonates do not shiver; they generate heat through **non-shivering thermogenesis** by metabolizing brown adipose tissue. * **Kangaroo Mother Care (KMC):** The gold standard for managing stable hypothermic neonates. * **WHO Classification:** * Normal: 36.5°C – 37.5°C * Cold Stress (Mild): 36.0°C – 36.4°C * Moderate Hypothermia: 32.0°C – 35.9°C * Severe Hypothermia: < 32.0°C
Question 15: Respiratory distress syndrome (RDS) in a neonate is primarily due to deficiency of which substance?
- A. Sphingomyelin
- B. Ceramide
- C. Dipalmitoyl lecithin (Correct Answer)
- D. All of the above
Explanation: **Explanation:** **Respiratory Distress Syndrome (RDS)**, also known as Hyaline Membrane Disease, is caused by a deficiency of **pulmonary surfactant**. Surfactant is a complex mixture of lipids and proteins synthesized by **Type II pneumocytes**. Its primary function is to reduce surface tension at the air-liquid interface of the alveoli, preventing alveolar collapse (atelectasis) during expiration. **Why Option C is correct:** The most abundant and active component of pulmonary surfactant (accounting for approximately 50-60% of its composition) is **Dipalmitoylphosphatidylcholine (DPPC)**, commonly known as **Dipalmitoyl lecithin**. It is the specific molecule responsible for the surface-tension-lowering properties of surfactant. **Why other options are incorrect:** * **A. Sphingomyelin:** This is a membrane phospholipid. While it is measured alongside lecithin to determine fetal lung maturity (L/S ratio), its concentration remains relatively constant during gestation and it does not possess the surfactant properties required to prevent RDS. * **B. Ceramide:** This is a precursor for sphingolipids and a signaling molecule involved in cell apoptosis and skin barrier function, but it plays no role in reducing alveolar surface tension. **High-Yield Clinical Pearls for NEET-PG:** * **L/S Ratio:** A Lecithin/Sphingomyelin ratio of **>2:1** in amniotic fluid indicates fetal lung maturity. * **Risk Factors:** Prematurity (most common), maternal diabetes, and Cesarean section without labor. * **Chest X-ray Findings:** Characterized by a diffuse **"ground-glass appearance"** and prominent air bronchograms. * **Management:** Antenatal corticosteroids (e.g., Betamethasone) given to the mother accelerate surfactant production; exogenous surfactant is the treatment of choice for the neonate.
Question 16: What is the common cause of neonatal hypoglycemia?
- A. Deficiency of glucagon
- B. Glycogen storage diseases
- C. Maple syrup urine disease
- D. Infant of diabetic mother (Correct Answer)
Explanation: **Explanation:** The correct answer is **Infant of Diabetic Mother (IDM)**. **1. Why IDM is the correct answer:** The primary mechanism is **fetal hyperinsulinism**. During pregnancy, maternal hyperglycemia leads to the transfer of high levels of glucose across the placenta to the fetus. In response, the fetal pancreas undergoes beta-cell hyperplasia and secretes excessive insulin. After birth, the high glucose supply is abruptly cut off, but the neonate’s insulin levels remain high, leading to rapid glucose uptake and inhibited gluconeogenesis, resulting in symptomatic hypoglycemia (usually within the first 1–2 hours of life). **2. Why the other options are incorrect:** * **Deficiency of glucagon:** While glucagon is a counter-regulatory hormone, isolated deficiency is an extremely rare cause of neonatal hypoglycemia compared to the high prevalence of IDM. * **Glycogen Storage Diseases (GSD):** These are rare metabolic disorders (e.g., Von Gierke disease). While they cause severe hypoglycemia, they typically manifest later in the neonatal period or infancy as fasting intolerance and hepatomegaly, rather than being the "common" cause. * **Maple Syrup Urine Disease (MSUD):** This is an amino acid metabolism disorder. While it presents with poor feeding and lethargy, hypoglycemia is not the primary or most common feature; it is characterized by ketoacidosis and a "maple syrup" odor in urine. **High-Yield Clinical Pearls for NEET-PG:** * **Definition:** Neonatal hypoglycemia is generally defined as blood glucose **<40 mg/dL** in the first 24 hours and **<50 mg/dL** thereafter. * **Other common causes:** Prematurity, Intrauterine Growth Restriction (IUGR/SGA), and Birth Asphyxia (due to rapid glycogen depletion). * **Management:** Asymptomatic cases are managed with early breastfeeding; symptomatic cases require an **IV bolus of 2 ml/kg of 10% Dextrose**, followed by a continuous Glucose Infusion Rate (GIR) of 6–8 mg/kg/min.
Question 17: A newborn has a fever of 103°F. Blood culture grows gram-positive cocci in chains. This is most likely to be which of the following?
- A. Group A Streptococci (Streptococcus pyogenes)
- B. Group B Streptococci (Streptococcus agalactiae) (Correct Answer)
- C. Salmonella species
- D. Streptococcus pneumoniae
Explanation: **Explanation:** The correct answer is **Group B Streptococci (GBS)**, also known as *Streptococcus agalactiae*. **Why Group B Streptococci is correct:** In the neonatal period (0–28 days), GBS is the **most common cause** of neonatal sepsis and meningitis worldwide. Microbiologically, GBS are **Gram-positive cocci in chains** and are typically β-hemolytic. They colonize the maternal vaginal tract, and the newborn acquires the infection during passage through the birth canal (vertical transmission). A high-grade fever (103°F) in a neonate with these Gram stain findings is a classic presentation of GBS sepsis. **Why the other options are incorrect:** * **Group A Streptococci (S. pyogenes):** While these are also Gram-positive cocci in chains, they are a rare cause of neonatal sepsis. They more commonly cause skin infections (impetigo) or pharyngitis in older children. * **Salmonella species:** These are **Gram-negative bacilli**. While they can cause sepsis in infants (especially in developing countries), they do not match the Gram stain description provided. * **Streptococcus pneumoniae:** These are **Gram-positive cocci in pairs (diplococci)** and are lancet-shaped. While a cause of sepsis, they are much less common than GBS in the immediate neonatal period. **Clinical Pearls for NEET-PG:** * **Top 3 causes of Neonatal Sepsis:** 1. Group B Streptococcus, 2. *E. coli*, 3. *Listeria monocytogenes*. * **Early-onset Sepsis (<72 hours):** Usually due to vertical transmission (GBS is the leader). * **Late-onset Sepsis (>72 hours):** Often due to environmental or nosocomial pathogens (CONS, *Staph aureus*). * **Drug of Choice:** For suspected neonatal sepsis, the empirical treatment is **Ampicillin + Gentamicin**.
Question 18: A neonate delivered at 38 weeks of gestation with a birth weight of 2.2 kg develops intolerance to feeds and abdominal distension on the second day of life. Physical examination is unremarkable. Sepsis screen is negative. PCV is observed to be 72%. What is the best management option?
- A. Hydration with IV Fluids
- B. Partial Exchange Transfusion (Correct Answer)
- C. Presumptive treatment for sepsis
- D. Medical Management for intestinal obstruction
Explanation: ### Explanation **Correct Option: B. Partial Exchange Transfusion** The clinical presentation is diagnostic of **Neonatal Polycythemia**. The neonate is Small for Gestational Age (SGA) (2.2 kg at 38 weeks), which is a major risk factor. A **Packed Cell Volume (PCV) or Hematocrit (Hct) ≥ 65%** (peripheral venous sample) confirms the diagnosis. The symptoms described—**feed intolerance and abdominal distension**—are classic signs of hyperviscosity syndrome. Increased red cell mass leads to sluggish blood flow in the microvasculature, causing mesenteric ischemia (leading to GI symptoms), hypoglycemia, and respiratory distress. **Partial Exchange Transfusion (PET)** is the treatment of choice for **symptomatic** neonates with a Hct between 65-70%, or any neonate with a Hct >70%. PET reduces the hematocrit to a target level (usually 50-55%) using Normal Saline, thereby decreasing viscosity while maintaining intravascular volume. **Why other options are incorrect:** * **A. Hydration with IV Fluids:** While hydration is supportive, it does not acutely lower the red cell mass effectively enough to resolve symptoms of hyperviscosity in a neonate with a PCV of 72%. * **C. Presumptive treatment for sepsis:** Although feed intolerance can mimic sepsis, the negative sepsis screen and the high PCV (72%) point specifically to polycythemia. * **D. Medical Management for intestinal obstruction:** Abdominal distension here is a functional result of hyperviscosity-induced gut ischemia, not a primary mechanical obstruction. --- ### Clinical Pearls for NEET-PG * **Definition:** Venous Hematocrit ≥ 65%. (Note: Capillary samples are unreliable and often higher). * **Common Risk Factors:** SGA, Infants of Diabetic Mothers (IDM), delayed cord clamping, and Twin-to-Twin Transfusion Syndrome. * **Formula for PET Volume:** $Volume (ml) = \frac{\text{Observed Hct} - \text{Desired Hct}}{\text{Observed Hct}} \times \text{Body Weight (kg)} \times \text{Blood Volume (80-90 ml/kg)}$ * **Most common metabolic complication:** Hypoglycemia (due to increased RBC glucose consumption). * **Target Hct post-exchange:** 50–55%.
Question 19: Hypoglycemia in a newborn is seen in which of the following conditions?
- A. Maternal hypothyroidism
- B. Intrauterine growth restriction and Macrosomia (Correct Answer)
- C. Maternal hypothyroidism and Rh incompatibility
- D. Intrauterine growth restriction and Rh incompatibility
Explanation: **Explanation:** Neonatal hypoglycemia is defined as a plasma glucose level **<40 mg/dL**. The correct answer is **Intrauterine Growth Restriction (IUGR) and Macrosomia** because both conditions disrupt the balance of glucose production and utilization. 1. **IUGR (Small for Gestational Age):** These infants have **decreased glycogen stores** in the liver and reduced subcutaneous fat. Due to placental insufficiency, they lack the energy reserves needed to maintain normoglycemia after birth. 2. **Macrosomia (often due to Maternal Diabetes):** These infants experience **fetal hyperinsulinism**. High maternal glucose crosses the placenta, stimulating the fetal pancreas to overproduce insulin. After birth, the glucose supply is cut off, but the high insulin levels persist, causing rapid glucose uptake and profound hypoglycemia. **Analysis of Incorrect Options:** * **Maternal Hypothyroidism (Options A & C):** This is generally not a direct cause of neonatal hypoglycemia. In contrast, maternal *hyperthyroidism* or poorly controlled diabetes are more significant risk factors. * **Rh Incompatibility (Options C & D):** While severe erythroblastosis fetalis can lead to pancreatic islet cell hyperplasia (causing hyperinsulinism), it is a less common cause compared to the combination of IUGR and Macrosomia. **NEET-PG High-Yield Pearls:** * **Most common cause:** Transient neonatal hypoglycemia is most often seen in Infants of Diabetic Mothers (IDM). * **Beckwith-Wiedemann Syndrome:** A classic triad of Macrosomia, Omphalocele, and Macroglossia, which also presents with severe hypoglycemia due to hyperinsulinism. * **Clinical Presentation:** Often asymptomatic, but may present with jitteriness, tremors, high-pitched cry, or seizures. * **Management:** Asymptomatic cases are managed with early breastfeeding; symptomatic cases require **IV 10% Dextrose (2 ml/kg bolus)** followed by a continuous infusion (GIR 6-8 mg/kg/min).
Question 20: Macrosomia is seen in all of the following conditions EXCEPT:
- A. Diabetes mellitus
- B. Obesity
- C. Hydrocephalus (Correct Answer)
- D. Post maturity
Explanation: **Explanation:** **Macrosomia** is defined as a birth weight >4000g or >4500g (regardless of gestational age) or a birth weight above the 90th percentile for gestational age. It refers to a generalized increase in body size and fat deposition. **Why Hydrocephalus is the Correct Answer:** Hydrocephalus involves an abnormal accumulation of cerebrospinal fluid (CSF) within the brain's ventricles, leading to an **enlarged head circumference (macrocephaly)**. While the head is disproportionately large, the overall body weight does not necessarily exceed the 90th percentile. Therefore, hydrocephalus causes macrocephaly, not true macrosomia. **Analysis of Incorrect Options:** * **Diabetes Mellitus:** Maternal hyperglycemia leads to fetal hyperglycemia, which stimulates the fetal pancreas to produce excess **insulin**. Since insulin is a potent anabolic hormone (fetal growth factor), it causes excessive deposition of fat and glycogen, leading to macrosomia. * **Obesity:** Maternal obesity is one of the most common risk factors for macrosomia due to increased nutrient availability and insulin resistance. * **Post-maturity:** Pregnancies exceeding 42 weeks allow for a longer period of intrauterine growth. If the placenta remains functional, the fetus continues to gain weight, often resulting in macrosomia. **High-Yield Clinical Pearls for NEET-PG:** * **Beckwith-Wiedemann Syndrome:** A classic high-yield cause of macrosomia characterized by the triad of macrosomia, macroglossia, and omphalocele. * **Infant of Diabetic Mother (IDM):** These infants are "large and plump" but have small brains (except for the heart and adrenals, most organs are enlarged). * **Complications:** Macrosomia increases the risk of shoulder dystocia, Erb’s palsy, and neonatal hypoglycemia.
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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