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Journal of Dental Sciences (2013) 8, 96e97
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CORRESPONDENCE
Dental management under general anesthesia
in an intellectually disabled adult patient with
phenylketonuria
Phenylketonuria (PKU) is an autosomal recessive disorder in
which the synthesis of tyrosine from phenylalanine is
impaired as the result of a deficiency of phenylalanine hydroxylase in the liver. The resulting accumulation of phenylalanine and its metabolites leads to central nervous
system disorders, such as mental retardation, spastic paralysis and epilepsy, and a variety of biochemical disorders.1e3
This report describes the case of a 42-year-old Japanese
woman with mental retardation and epilepsy associated
with PKU, who underwent dental caries treatment under
general anesthesia. She was diagnosed with PKU at 2 years
old. Consequently, she underwent phenylalanine-restricted
diet therapy, and yet she was diagnosed with sequelae
of PKU and mental retardation at 14 years old. Oral administration of therapeutic phenylalanine-free milk, pantethine, and magnesium sulfate was restarted, but she did
not respond well to the diet therapy. She was
also prescribed carbamazepine for epileptic seizure but
still developed seizures several times a year. In addition,
bromperidol and piperiden were prescribed for psychiatric
symptoms such as auditory hallucinations and obsessions.
For perioperative anesthetic management of patients
with PKU, it is important to prevent increased activity of
enzymes involved in amino acid metabolism and excessive
increase in glycolysis or protein catabolism, all of which
may be caused by preoperative restriction of oral intake
and surgical stress.4 Therefore, arterial blood samples were
collected before anesthesia induction, during surgery, and
after extubation to measure plasma concentrations of
cortisol, phenylalanine, and tyrosine based on the stress
response during dental treatment and the effects of anesthetics that were evaluated (Table 1).
Anesthesia was induced with intravenous propofol,
fentanyl, and rocuronium under inhaled oxygen and
nitrous oxide. Anesthesia was maintained with oxygen,
nitrous oxide, 1e2 mg/mL propofol with target controlled
infusion (TCI), and 0.1 mg/kg/min remifentanil. Propofol
and remifentanil have short durations of action and thus
provide high controllability and early recovery. The use of
these anesthetics was also effective for reducing the
intra-operative stress response and for preventing an
increase in plasma phenylalanine concentration, as shown
by the decrease in plasma cortisol concentration. In
addition, as the treatment procedures used in the present
case were minimally invasive, the concomitant use of
nitrous oxide reduced the doses of propofol and remifentanil and provided stable perioperative respiratory and
hemodynamic status, suggesting the usefulness of the
concomitant use of nitrous oxide in the anesthetic management of PKU patients. The patient was maintained in
a stable condition with no occurrence of seizure, psychomotor excitement symptoms, or any other serious
neurological symptoms in their perioperative care. We
obtained patient consent the for publication of personal
information.
Adult PKU patients are required to adhere to a therapeutic milk-based strict dietary restriction. The present
patient had multiple dental caries despite oral hygienic
management. Because patients with PKU who develop
mental retardation and epilepsy as a result of inadequate
phenylalanine-restricted diet therapy have a risk of cardiovascular or metabolic disorders associated with dental
caries or periodontal disease, strict oral hygiene must be
maintained.
1991-7902/$36 Copyright ª 2013, Association for Dental Sciences of the Republic of China. Published by Elsevier Taiwan LLC. All rights reserved.
http://dx.doi.org/10.1016/j.jds.2012.12.003
Correspondence
Table 1
97
Perioperative changes of serum amino acid concentration.
Serum concentrationa
Preoperative
Intraoperative
Recovery room
Phenylalanine (nmol/L) (42.6e75.7)
Tyrosine (nmol/L) (40.4e90.3)
Cortisol (mg/dL) (4.0e18.3)
1485.4
28.6
4.0
1426.6
26.8
2.7
1431.3
27.7
2.1
a
Normal ranges are shown in parentheses.
References
1. Seashore MR, Friedman E, Novelly RA, Baoat V. Loss of intellectual function in children with phenylketonuria after relaxation of dietary phenylalanine restriction. Pediatrics 1985;75:
226e32.
2. Villasana D, Butler IJ, Williams JC, Roongta SM. Neurological
deterioration in adult phenylketonuria. J Inherit Metab Dis
1989;12:451e7.
3. Cabalska B, Duczynska N, Boryzymowska J, Zorska K, Folga AK,
Bozkowa K. Termination of dietary treatment in phenylketonuria. Eur J Pediatr 1977;123:253e62.
4. Miyazawa A, Nagano K, Yamanak I. Anesthetic management of
children with phenylketonuria. J Clin Anesth 1995;19:1527e8
[In Japanese, English abstract].
Yoko Matsushita
Yoshihiro Momota*
Naotaka Kishimoto
Junichiro Kotani
Department of Anesthesiology, Osaka Dental University,
Osaka, Japan
*Corresponding author. Department of Anesthesiology,
Osaka Dental University, 1-5-17, Otemae, Chuo-ku,
Osaka 540-0008, Japan.
E-mail address: [email protected] (Y. Momota)
Received 16 October 2012
Final revision received 11 December 2012