Objectives: To present clinical and laboratory findings in the case of a term newborn with conjugated hyperbilirubinaemia and to stress the importance of differential diagnosis.
Results: A term newborn delivered by caesarean section (birth weight 2550 g, birth length 47 cm, value of Apgar score 9/10) with good direct adaptation had on the first day of life increased levels of conjugated bilirubin (23 micromol/l), unconjugated bilirubin (55 micromol/l) and C-reactive protein 39.4 g/l. The diagnosis of mevalonic aciduria was confirmed by urine analysis (mevalonolactone 393 micromol/mmol crea, normal range <2.0 micromol/mmol crea; mevalonic acid 40.5 micromol/mmol crea, normal range <0.04 micromol/mmol crea).
Conclusion: Mevalonic aciduria can be clinically distinguished based on symptoms of neurological involvement. It can also present itself with hepatosplenomegaly, lymphadenopathy, anaemia, leukocytosis, increased sedimentation rates and levels of C-reactive protein. In cases of conjugated hyperbilirubinaemia of unknown aetiology it is important to exclude mevalonic aciduria by urine investigation for organic acids.