Background: Aromatic l-amino acid decarboxylase (AADC) deficiency is a rare autosomal recessive disorder. The AADC enzyme plays an important role in the synthesis of monoamine neurotransmitter like dopamine and serotonin. Lack of the AADC enzyme would lead to reduced concentration of biogenic amines and metabolites in cerebrospinal fluid and result in autonomic dysfunction and movement disorder with symptoms such as oculogyric crises, limb dystonia, neurologic dysfunction and impaired movements. Hemodynamic instability, poor thermoregulation, and hypoglycemia due to AADC may seriously influence anesthetic managements.
Case report: Eight patients with AADC deficiency were enrolled in the study. All patients were older than 24 months and indicated for stereotactic surgery. They received general anesthesia (GA) for both MRI scan and stereotactic surgery within a week interval. All patients tolerated GA without complications. The average duration for MRI scan was 93 minutes, and 521 minutes for stereotactic surgery. During the MRI scan, only 1 patient received vasoactive agent once, and the hemodynamics were stable in other patients. Extubation were performed right after the procedure, and all patients were sent to intensive care units (ICU) for further observation. No respiratory complications were noted throughout the ICU stay. For the stereotactic surgery, 4 patients needed inotropic support. During the surgery, neither hypoglycemia nor hypo- or hyperthermia were detected. All patients were sent to ICU for post-operative care, and extubation were performed smoothly.
Discussion: Due to reduced concentration of catecholamine and intact parasympathetic activity, anesthetic management in AADC deficiency patients is challenging. In our case series, hemodynamics of AADC deficiency patients were stable during GA for minor procedure such as MRI scan. However, in major surgeries, inotropic or vasoactive support might be necessary. Our study shows that GA can be conducted safely in AADC deficiency patients with careful monitoring.

Anaesthesia in patients of aromatic L-amino acid decarboxylase (AADC) deficiency for MRI scan and stereotactic surgery