A 28-week neonate on mechanical ventilation develops sudden oxygen desaturation, hypotension, and bulging fontanelle on day 3 of life. Cranial ultrasound shows Grade IV intraventricular hemorrhage. What is the SINGLE MOST IMPORTANT predisposing factor for Grade III-IV IVH in preterm neonates?
- A Fluctuating cerebral blood flow due to impaired autoregulation ✓
- B Polycythemia causing increased blood viscosity
- C Thrombocytopenia due to maternal antiplatelet antibodies
- D Hyperbilirubinemia causing kernicterus in the germinal matrix
Correct answer: A. Fluctuating cerebral blood flow due to impaired autoregulation
Explanation
Grade III-IV IVH in preterm neonates originates in the highly vascularized germinal matrix, which has pressure-passive cerebral blood flow (impaired autoregulation). Fluctuations in CBF—due to pneumothorax, hypercapnia, hypoxia, or aggressive ventilation—cause rupture of fragile germinal matrix vessels. Polycythemia and thrombocytopenia are contributing but not the primary pathophysiological mechanism. Kernicterus affects the basal ganglia but not the germinal matrix specifically.
Reference: Ghai Essential Pediatrics, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.