(Trisomy 18)

Prevalence: 1/8000 live births. The majority of cases are sporadic but hereditary forms are possible if a parent has a balanced translocation. Congenital chromosomal aberration (most common after trisomy 21) characterized by the presence of a supernumerary chromosome 18 in all cells (complete form: 94 % of cases) or only in certain cell populations (mosaic form: 4 % of cases, the severity of which varies depending on the type and number of the affected cells ). Very rarely (2 % of cases), a part of the long arm (q) of chromosome 18 binds to another chromosome during the formation of reproductive cells. As a consequence, the affected individuals have two normal copies of the chromosome 18, plus the additional material of chromosome 18 attached to another chromosome: this is called a partial trisomy 18. If only part of the q arm is present in three copies, the physical signs of partial trisomy 18 are less severe than those observed in the complete form. If the entire q arm is present in three copies, individuals can be as severely affected as if they had three complete copies of chromosome 18.

Significant prenatal mortality either natural or as a result of a medical termination of pregnancy.

Clinical presentation:

-        intrauterine growth retardation (intrauterine death in 90 % of cases)

-        dysmorphism: narrow skull (sometimes microcephaly), dolichocephaly with microretrognathia, the external ears are  small, low-set,  with a small lobule and an unfolded helix that is simple and sometimes attached to the scalp'faun

-        microphthalmia, hypertelorism, coloboma; photophobia (requisite wearing of sunglasses)

-        apnea: central (absences ?) or obstructive

-        short neck with skin excssive folds

-        congenital heart disease (95 % of cases): ASD, VSD, valvular pathology

-        brain abnormalities: agenesis of the corpus callosum, cerebellar hypoplasia, convulsions (25-50 %)

-        neonatal hypotonia, sometimes picture of arthrogryposis at birth; hypertonia in childhood

-        kidney abnormalities: hydronephrosis, agenesis, horseshoe kidney

-        characteristic hands: closed fists, middle finger covered by the index and pinkie covering the ring finger and  clubfeet (50 %),flexed big toe and prominent heels (rocker-bottom feet)

-        early scoliosis

-        sometimes esophageal atresia, omphalocele or diaphragmatic evisceration, spina bifida, cleft lip / palate.

-        increased risk of nephroblastoma and hepatoblastoma.

Often death in the neonatal period or before 1 year of age (10 % survival) from cardiac (pulmonary arterial hypertension) or respiratory failure. However, some recent data show that the survival chances are better as, in the past, the diagnosis  often led to a decision of therapeutic abstention.

Anesthetic implications: 

preoperative echocardiography. Risk of difficult mask ventilation and intubation. The small mouth opening can render the use of a laryngeal mask or videolaryngoscope impossible. Difficult venous access. One case of rigidity followed by hyperthermia and raised CPK levels has been reported after administration of succinylcholine.

References : 

-        Matsuda H, Kaseno S, Gotoh Y, Furukawa K, Imanaka K.
Muscle rigidity caused by succinylcholine in Edwards’ syndrome.
Masui 1983 ; 32:125-8

-        Bailey C, Chung R.
Use of the laryngeal mask airway in a patient with Edward's syndrome.
Anaesthesia. 1992;47:713

-        Ochiai N, Okutani R, Yoshimura Y.
Anesthetic management of a patient with partial trisomy 18.
J Anesth 1995; 9:78-80

-        Miller C, Mayhew JF.
Edward's syndrome (trisomy 18).
Paediatr Anaesth 1998; 8:441-2.

-        Courreges  P, Nieuviarts  R, Lecoutre D. 2003.
Anaesthetic management for Edwards syndrome.
Paediatr Anaesth 2003; 13:267-9

-        Cereda A, Carey JC.
The Trisomy 18 syndrome.
Orphanet J Rare Diseases 2012 ; 7: 81

-        Mifsud S, Bezzina M, Paris S.
Anesthetic management of a patient with Edwards syndrome.
Clin Case Rep. 2016;4 :740-2.

-        Wingate JR, Adachi I, Fenton K, Janvier A, Farlow B, Mossad EB.
Case 14-2014: Tetralogy of Fallot with severe cyanosis in an infant with trisomy 18: ethical dilemmas in the perioperative period.
J Cardiothorac Vasc Anesth 2014; 28 :1677-85.

-        Birmingham EE, Stucke AG, Diaz CD.
Anesthesia for children with complete trisomy 18 (Edwards syndrome): a cohort review of 84 anesthesia encounters in nine patients.
Pediatr Anesth 2021 ; 31 : 419-28.

-        Matthews LJ, Mpody C, Nafiu OO,  Tobias JD.
Morbidity and mortality following noncardiac surgical procedures among children with autosomal trisomy.
Pediatr Anesth 2022 ; 32 : 681-6.

Updated: March 2023