NPS Neonatal Physiology and Pathophysiology Flashcards

What is the most common chromosomal cause of hydrops fetalis in the US?

Answer: Turner syndrome (45,X)

Turner syndrome (45,X) is the most common chromosomal cause of non-immune hydrops fetalis due to lymphatic dysplasia causing nuchal cystic hygroma and generalized edema.

A neonate presents with hypoglycemia, macrosomia, and polycythemia. What is the most likely maternal history?

Answer: Poorly controlled gestational diabetes

Infant of a diabetic mother (IDM) classically presents with macrosomia (from fetal hyperinsulinism), hypoglycemia after birth, and polycythemia from elevated fetal EPO.

Which condition causes hypocalcemia in neonates born to mothers with hyperparathyroidism?

Answer: Maternal hypercalcemia suppresses fetal parathyroid gland development

Maternal hypercalcemia chronically suppresses fetal parathyroid gland development; after birth, the neonate cannot maintain calcium without maternal supply, causing severe hypocalcemia.

Bell's staging system is used to classify the severity of which neonatal condition?

Answer: Necrotizing enterocolitis

Bell's staging classifies NEC into Stage I (suspected), Stage II (proven), and Stage III (advanced/complicated), guiding management decisions including surgery.

Why does therapeutic hypothermia (TH) reduce brain injury in hypoxic-ischemic encephalopathy (HIE)?

Answer: It attenuates the secondary energy failure phase by suppressing glutamate excitotoxicity and apoptosis

TH targets the secondary injury phase (6–72 hours after hypoxia), reducing glutamate excitotoxicity, free radical generation, inflammation, and apoptosis.

A term neonate is noted to have a 'double bubble' sign on abdominal X-ray. What is the most likely diagnosis?

Answer: Duodenal atresia

The 'double bubble' sign (distended stomach + dilated proximal duodenum with no distal gas) is pathognomonic for duodenal atresia.