bilirubininduced

Bilirubin-induced refers to tissue injury caused by elevated bilirubin, most often unconjugated bilirubin, which in neonates can cross the immature blood-brain barrier and cause neurotoxicity. The phrase is commonly used in relation to bilirubin-induced neurologic dysfunction (BIND) and kernicterus.

Causes and risk factors include severe neonatal jaundice from hemolysis (such as Rh incompatibility or G6PD deficiency), prematurity with immature clearance, and conditions that raise bilirubin production or reduce albumin binding. Certain drugs can displace bilirubin from albumin, increasing free bilirubin.

Pathophysiology: Unconjugated bilirubin is lipophilic and can accumulate in the brain, especially basal ganglia and brainstem, when the protective barriers are immature or overwhelmed. Toxicity involves neuronal injury, mitochondrial dysfunction, and inflammatory responses, leading to long-term motor and cognitive sequelae.

Clinical features: Early signs include lethargy, poor feeding, and hypotonia; as bilirubin rises, irritability, high-pitched cry, arching of the back, and seizures may occur. Chronic exposure causes movement disorders such as choreoathetosis and can contribute to hearing loss and cognitive impairment.

Diagnosis: Assessment combines total and unconjugated bilirubin levels, age, and risk factors. Transcutaneous bilirubinometry and serum measurements guide treatment thresholds. Neuroimaging, especially MRI, may show characteristic signal changes in the globus pallidus in established kernicterus.

Management: The primary goal is rapid reduction of circulating unconjugated bilirubin. Phototherapy is first-line for many cases; exchange transfusion is used for severe hyperbilirubinemia or rapidly rising levels. Ongoing care includes addressing underlying causes and monitoring for neurologic sequelae.

Prognosis and prevention: Timely treatment can prevent kernicterus and associated deficits; delayed therapy increases risk of permanent neurologic injury. Prevention strategies include newborn jaundice screening, risk-based phototherapy, adequate hydration, and avoiding drugs that displace bilirubin.