Characterizing and Defining “Infantile Liver Failure”
The article “Liver Failure in Early Infancy: Aetiology, Presentation, and Outcome” made an interesting read and brought forward few points regarding acute liver failure (ALF) in infants younger than 120 days of life. The largest single etiology causing ALF described here was hypoxia-ischemia (HI) due to perinatal insults in 15 (19%) (1). In infants younger than 90 days of age, although shock has been described as a cause of ALF in 6 of 148 (4.1%) (2), HI due to perinatal insults causing pediatric acute liver failure (PALF) is not previously described (2–4). Literature reveals that asphyxiated newborns have marginally higher international normalized ratio (INR) (1.49 ± 0.12 vs 1.13 ± 0.07, P < 0.001) (5), which improves by day 3 (day 1, 2.09 ± 1.21; day 3, 1.30 ± 0.21) (6). Marked elevation of transaminases, typical for ischemic hepatitis, was not described in infants with HI from the current series. Encephalopathy was present in 20% of infants with HI (1). As encephalopathy is difficult to diagnose in infants and is one of the components of perinatal asphyxia, defining PALF with INR >1.5 and encephalopathy is incorrect in these infants. Hence, it needs clarification whether HI was actually a cause of PALF in these infants, and if so, apparently the liver failure in this group was mild and transient.
The authors also mentioned exclusion of infants with recognized liver disease who decompensated within 120 days (1). It is, however, difficult to differentiate ALF from decompensated liver disease in this age group. Metabolic liver diseases such as tyrosinemia, galactosemia, and mitochondriopathies can decompensate within 120 days of life but are classified as ALF. Neonatal hemochromatosis, although presents as ALF, but histopathology often shows cirrhosis by time of presentation. Hence, the definition of PALF, which needs exclusion of underlying chronic liver disease cannot be applied in this age group and needs a relook (3). The better terminology would be “infantile liver failure” defined as coagulopathy alone (corrected INR >2) without mention of “acute,” “encephalopathy,” or “absence of underlying cirrhosis.