A 2-day-old term neonate given IV chloramphenicol becomes gray, hypothermic, and hypotensive with abdominal distension. The underlying mechanism of this syndrome is:

• A Direct toxic injury to the neonatal myocardium
• B Idiosyncratic immune-mediated hemolysis
• C Displacement of bilirubin from albumin causing kernicterus
• D Immature hepatic glucuronyl transferase leading to drug accumulation ✓

Explanation

The gray baby syndrome results from inadequate conjugation of chloramphenicol by hepatic glucuronyl transferase combined with immature renal excretion, producing very high free drug levels. The accumulated drug blocks mitochondrial protein synthesis and oxidative phosphorylation in the infant, causing cardiovascular collapse. Displacement of bilirubin occurs but causes kernicterus, not the gray, shocked picture described here.

Reference: Katzung Basic and Clinical Pharmacology, 15th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.