Neonatology — MCQs

Neonatology Indian Medical PG Practice Questions and MCQs

Question 941: Meconium typically passes within how many hours after birth in a healthy baby?

A. 96 hours
B. 72 hours
C. 24 hours (Correct Answer)
D. 48 hours

Explanation: ***24 hours*** - In a **healthy, term newborn**, the first passage of **meconium** usually occurs within the first **24 hours after birth**. - Delay beyond this period may indicate a range of conditions from **intestinal obstruction** to **Hirschsprung disease**. *72 hours* - While some mild delays can occur, 72 hours is generally considered a significantly **delayed passage** of meconium, warranting further investigation. - A delay this long often suggests an underlying issue rather than normal physiological variation. *96 hours* - Meconium passage at 96 hours (4 days) is a significant **red flag** and would almost certainly indicate a **pathological condition** requiring urgent medical evaluation. - It falls well outside the normal timeframe for meconium excretion. *48 hours* - Passing meconium within 48 hours is acceptable in some cases, particularly in **premature infants** or those with **perinatal stress**. - However, the optimal and most common timeframe for a healthy baby is within the first 24 hours, making 24 hours the "most likely" and expected answer.

Question 942: Full-term, small-for-date babies are at high risk of:

A. Hypoglycemia (Correct Answer)
B. Intraventricular haemorrhage
C. Bronchopulomonary dysplasia
D. Hyperthermia

Explanation: ***Hypoglycemia*** - **Small-for-date** babies often have reduced glycogen stores due to **intrauterine growth restriction (IUGR)**, making them prone to hypoglycemia. - Their increased metabolic rate relative to their small size further exacerbates the risk of glucose depletion. *Intraventricular haemorrhage* - This condition is primarily associated with **prematurity**, particularly in very low birth weight infants, due to the fragility of their germinal matrix vessels. - While small-for-date babies can be premature, being **full-term** significantly reduces this specific risk. *Bronchopulomonary dysplasia* - **Bronchopulmonary dysplasia (BPD)** is a chronic lung disease predominantly observed in **premature infants** who have received prolonged mechanical ventilation and oxygen therapy. - A **full-term** infant, even if small-for-date, is much less likely to develop BPD. *Hyperthermia* - Small-for-date babies are generally at higher risk of **hypothermia** due to their larger surface area to volume ratio and reduced subcutaneous fat. - While any neonate can experience hyperthermia from external factors (e.g., overheating), it is not a specific risk related to their small-for-date status.

Question 943: Using the formula for Ponderal Index (PI = weight in kg / (height in m)^3), calculate the Ponderal index of a baby weighing 2000 grams and measuring 50 centimeters in length at birth.

A. 32
B. 8
C. 4
D. 16 (Correct Answer)

Explanation: ***16*** - Begin by converting the baby's weight from grams to kilograms: 2000 grams = **2 kg**. - Next, convert the baby's height from centimeters to meters: 50 centimeters = **0.5 m**. - Apply the Ponderal Index formula: PI = weight (kg) / (height (m))³ = 2 kg / (0.5 m)³ - Calculate (0.5)³ = 0.5 × 0.5 × 0.5 = **0.125** - Therefore: PI = 2 / 0.125 = **16** - This value indicates a relatively thin baby, consistent with the **low birth weight of 2000 grams**. *8* - This incorrect value would result from errors in the calculation, such as incorrectly computing (0.5)³ or making arithmetic mistakes in the division. - The correct calculation yields 16, not 8. *32* - This result would occur if the weight was incorrectly doubled (4 kg instead of 2 kg) in the calculation. - Alternatively, this could result from incorrectly calculating the denominator as (0.5)³ = 0.0625 instead of 0.125. *4* - This answer might arise from dividing by (0.5)² = 0.25 instead of (0.5)³ = 0.125, essentially using a squared power instead of cubed. - Or from incorrectly converting the weight to 0.5 kg instead of 2 kg.

Question 944: As per the latest NRP guidelines, what is the target preductal saturation after birth at 5 minutes?

A. 65% - 70%
B. 75% - 85%
C. 85% - 95%
D. 80% - 85% (Correct Answer)

Explanation: ***80% - 85%*** - The Neonatal Resuscitation Program (NRP) guidelines recommend target pulse oximetry readings for **preductal oxygen saturation** in newborns. - At **5 minutes after birth**, the expected preductal saturation range is **80% - 85%**. - This represents the specific target for the 5-minute mark according to current NRP guidelines. *65% - 70%* - This range is the target for **2 minutes after birth**, reflecting the early transition from fetal circulation. - It is **too low** for the target saturation at 5 minutes post-delivery according to NRP. *75% - 85%* - This range is **too broad** and spans multiple time points (3-5 minutes). - The lower end (75%) represents the target at **3 minutes**, while 80-85% is specifically for **5 minutes**. - NRP guidelines specify **80-85%** as the precise target range for 5 minutes, not 75-85%. - This option is incorrect because it does not reflect the **specific** 5-minute target. *85% - 95%* - This higher range is the target for **10 minutes after birth**, indicating the near-complete transition to extrauterine circulation. - It is **too high** for the expected preductal saturation at 5 minutes according to current NRP guidelines.

Question 945: Microcephaly is commonly associated with maternal exposure to the following substances or conditions, except which of the following?

A. Alcohol intake
B. Cytomegalovirus (CMV) infection
C. Varicella
D. Caffeine intake (Correct Answer)

Explanation: ***Caffeine intake*** - **Caffeine consumption** during pregnancy in moderate amounts (less than 200-300 mg/day) is generally considered safe and is **not a known cause of microcephaly**. - While excessive caffeine can lead to other issues like low birth weight or miscarriage risk, it does not affect **brain development** to the extent of causing microcephaly. - Major health organizations including ACOG consider moderate caffeine safe during pregnancy. *Alcohol intake* - **Maternal alcohol intake** can lead to **Fetal Alcohol Spectrum Disorders (FASD)**, which commonly include **microcephaly** as a prominent feature. - Alcohol is a potent **teratogen** that causes significant damage to the developing brain, resulting in reduced brain growth and head circumference. - No safe level of alcohol consumption during pregnancy has been established. *Cytomegalovirus (CMV) infection* - **Congenital CMV infection** is the most common congenital viral infection and a leading cause of **microcephaly**. - Part of the **TORCH infections** (Toxoplasmosis, Others, Rubella, CMV, Herpes), CMV causes significant neurodevelopmental damage. - Classic features include microcephaly, intracranial calcifications (periventricular), sensorineural hearing loss, and chorioretinitis. *Varicella* - **Maternal varicella (chickenpox) infection** during pregnancy, particularly in the first or second trimester, can lead to **congenital varicella syndrome**. - This syndrome includes **microcephaly**, cortical atrophy, limb hypoplasia, skin scarring, and eye abnormalities. - The risk is highest with maternal infection between 8-20 weeks of gestation.

Question 946: A neonate delivered at 32 weeks, is put on a ventilator, and the X-ray shows "white out lung" with an arterial blood gas (ABG) revealing a PaO2 of 75 mmHg. The ventilator settings are an FiO2 of 70% and a rate of 50 breaths per minute. The next step to be taken should be?

A. Increase rate to 60 per minute
B. Continue ventilation with the same settings (Correct Answer)
C. Weaning ventilator
D. Increase FiO2 to 80

Explanation: ***Continue ventilation with the same settings*** - The neonate has a PaO2 of 75 with an FiO2 of 70%, which indicates **adequate oxygenation** despite the "white out lung" on the X-ray, likely due to **respiratory distress syndrome**. - No immediate changes to ventilator settings are necessary as the current settings are achieving the desired therapeutic outcome for oxygenation (PaO2 75 is acceptable). *Increase rate to 60 per minute* - Increasing the respiratory rate primarily impacts **PaCO2 levels**, not directly PaO2, and the question does not provide PaCO2 values indicating a need for adjustment. - An increased rate without a clear indication could lead to **ventilator-induced lung injury** or other complications. *Increase FiO2 to 80* - The current PaO2 of 75 mmHg on an FiO2 of 70% is within an **acceptable range** for a premature neonate. - Increasing FiO2 further would expose the infant to potentially **toxic levels of oxygen** without clear benefit, increasing the risk of **retinopathy of prematurity** and chronic lung disease. *Weaning ventilator* - Weaning the ventilator would be premature, given the "white out lung" and the need for **70% FiO2** to maintain adequate oxygenation. - This suggests the neonate still has significant respiratory compromise, making immediate weaning **unsafe** and likely to lead to respiratory failure.

Question 947: What is the weight range that defines a low-birth-weight baby?

A. <2.5 kg (Correct Answer)
B. >3.5 kg
C. 2.5-3.0 kg
D. 3.0-3.5 kg

Explanation: ***<2.5 kg*** - A **low-birth-weight (LBW)** baby is defined as weighing less than 2.5 kilograms (5.5 pounds) at birth, regardless of gestational age. - This weight threshold is a critical indicator for increased risk of **neonatal morbidity and mortality**. *>3.5 kg* - A birth weight greater than 3.5 kg (7.7 pounds) is considered **macrosomia** or a large baby, which has its own associated risks. - This weight range is generally considered healthy or indicative of a larger-than-average baby, not a low-birth-weight one. *2.5-3.0 kg* - This weight range is generally considered **within the normal, healthy range** for term infants. - While on the lower end of normal, it does not meet the clinical definition of a low-birth-weight baby. *3.0-3.5 kg* - This weight range is also considered **normal and healthy** for most term infants. - Babies in this range typically have better health outcomes compared to those with low birth weight.

Question 948: A neonate presents with recurrent seizures, hypocalcemia, and recurrent infections. What is the diagnosis?

A. DiGeorge syndrome (22q11.2 deletion syndrome) (Correct Answer)
B. Bardet-Biedl syndrome
C. Gitelman syndrome (hypokalemic metabolic alkalosis)
D. Idiopathic hypercalciuria (calcium wasting)

Explanation: ***DiGeorge syndrome (22q11.2 deletion syndrome)*** - This syndrome is characterized by **thymic hypoplasia/aplasia** (leading to **T-cell immunodeficiency** and recurrent infections) and **parathyroid hypoplasia/aplasia** (leading to **hypocalcemia** and seizures). - Other common features include **cardiac anomalies** (especially conotruncal defects) and distinctive **facial features**. *Bardet-Biedl syndrome* - This is a rare genetic disorder characterized by **retinal dystrophy**, **polydactyly**, **obesity**, **renal dysfunction**, and **intellectual disability**. - It does not typically present with the combination of severe immunodeficiency, hypocalcemia, and seizures as primary symptoms in neonates. *Gitelman syndrome (hypokalemic metabolic alkalosis)* - This is a renal tubular disorder characterized by **hypokalemia**, **hypomagnesemia**, and **metabolic alkalosis**, usually presenting in late childhood or adulthood. - It involves impaired reabsorption of sodium chloride in the distal convoluted tubule and is not associated with recurrent infections or hypocalcemia presenting as seizures in neonates. *Idiopathic hypercalciuria (calcium wasting)* - This condition involves excessive **calcium excretion in the urine** without an apparent cause and can lead to kidney stones or osteoporosis in older individuals. - It does not cause hypocalcemia, recurrent infections, or seizures in neonates; in fact, the name implies a loss of calcium from the body through urine, not a deficiency in the blood.

Question 949: Caudal regression syndrome is seen in babies of mothers having which of the following conditions?

A. PIH
B. Anemia
C. Cardiac disease
D. Diabetes (Correct Answer)

Explanation: ***Diabetes*** - **Caudal regression syndrome** (sacral agenesis) is a rare but severe congenital anomaly characterized by abnormal development of the caudal (lower) spine and spinal cord - It is **strongly associated** with **maternal diabetes**, particularly pregestational and poorly controlled diabetes mellitus - The risk is approximately **200-600 times higher** in infants of diabetic mothers compared to the general population - Poor glycemic control during organogenesis (first trimester) is the key pathogenic factor *PIH* - Pregnancy-induced hypertension (PIH) can lead to intrauterine growth restriction and placental insufficiency - **Not associated** with caudal regression syndrome or major structural anomalies of the spine *Anemia* - Maternal anemia can impact fetal growth and oxygen delivery - **No established link** to caudal regression syndrome or neural tube/spine developmental defects *Cardiac disease* - Maternal cardiac disease may affect fetal oxygenation and hemodynamics - **Not a risk factor** for caudal regression syndrome or spinal developmental anomalies

Question 950: What is the most appropriate treatment for a clinically significant pneumothorax in a newborn requiring intervention?

A. Needle decompression
B. Chest tube insertion (Correct Answer)
C. Oxygen therapy
D. Administration of surfactant

Explanation: ***Chest tube insertion*** - A **chest tube** is indicated for a clinically significant pneumothorax in a newborn to effectively **evacuate air** from the pleural space and allow lung re-expansion. - This procedure provides **continuous drainage** and prevents tension pneumothorax, ensuring adequate ventilation and oxygenation. *Oxygen therapy* - While supportive, **oxygen therapy alone** is insufficient for a clinically significant pneumothorax that requires intervention to remove trapped air. - It only addresses **hypoxemia** but does not resolve the underlying issue of air accumulation in the pleural space. *Administration of surfactant* - **Surfactant administration** is primarily used to treat or prevent **respiratory distress syndrome** in preterm infants by improving lung compliance. - It does not directly treat a pneumothorax, which is a mechanical problem of air leakage into the pleural space. *Needle decompression* - **Needle decompression** is an emergency temporizing measure for a **tension pneumothorax** in older children or adults. - In newborns, it is less common due to the small chest size and risk of injury to underlying structures; **chest tube insertion** is generally preferred for definitive management.

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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