Children with bilateral temporal arachnoid cysts may have glutaric aciduria type 1 (GAT1); operation without knowing that may be harmful.

BACKGROUND: Bilateral, temporal arachnoid cysts are common in patients with Glutaric aciduria type 1 (GAT1). The present study investigates whether bitemporal cysts may occur unrelated to GAT1. and it reports our experience with 2 GAT1 patients.
METHODS: During the last 11 years, the regional neurosurgical department has seen a total of 147 patients with arachnoid cysts in a population of 890,000. Eight of these patients had bitemporal arachnoid cysts, 4 boys, 3 adult females, and 1 adult male. Urine from 7 of these patients was examined with gas chromatography-mass spectrometry.
FINDINGS: Large amounts of glutaric acid were discovered in the urine of only 2 of these patients, both young boys with severe neurological symptoms of the disease. One of them died 2 years after the clinical start of the disease. The remaining 5 urinary specimens contained low (normal) concentrations of glutaric acid.
INTERPRETATION: For neurosurgeons, it is important to recognise that children with bitemporal arachnoid cysts may have GAT1, and that even simple surgical procedures may be extremely harmful for such patients. All paediatric patients with bitemporal arachnoid cysts should therefore be screened for GAT1 before any surgical procedure takes place, especially if there is also macrocephaly, an acute encephalitis-like illness, or a dystonic, cerebral palsy-like condition. It is concluded that bitemporal arachnoid cysts are extremely rare, and that they may well occur unrelated to GAT1.