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A 35-year-old female with Down syndrome and a history of a repaired ventricular septal defect presents for dental extraction and restorations. The patient has a history of obstructive sleep apnea.
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Laboratory: Hematocrit 48%
Echocardiography: Mild right ventricular hypertrophy, mild to moderate pulmonary hypertension
Physical examination: 80 kg, 5 ft 1 in, Down facies, macroglossia, poor dentition, oxygen saturation 92% on room air
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PREOPERATIVE CONSIDERATIONS
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Down syndrome, also known as trisomy 21, is the most common chromosomal disorder found in the general population; it results from an extra copy of chromosome 21 and occurs in about 0.15% of live births. The risk increases with maternal age.
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Patients with Down syndrome have characteristic features that are readily recognized, including microcephaly, mongoloid facies (flat face and oblique palpebral fissures), midface hypoplasia, and a simian crease. Hypotonia is another common clinical feature found in these patients, and this can affect the patency of their airways. When this is coupled with a narrow nasopharynx, macroglossia, laryngomalacia, short neck, and enlarged tonsils and adenoids, they are susceptible to chronic upper airway obstruction, leading to arterial hypoxemia and the development of pulmonary arterial hypertension. There is also an increased incidence of subglottic stenosis and tracheal stenosis because of complete tracheal rings.
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These patients have varying degrees of mental retardation ranging from mild intellectual impairment to severe mental retardation. They tend to be very good babies, and as they get older, they tend to be content, cheery, good-natured and happy individuals with some degree of stubbornness.
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Approximately 40% of children with Down syndrome have congenital heart disease, with the most common anomalies being endocardial cushion defects (50%), ventricular septal defects (25%), and atrial septal defects (10-15%). Perioperative mortality and morbidity for surgical cardiac correction are higher than for those without Down syndrome, which may be attributed to postoperative atelectasis and pneumonia, and preexisting pulmonary hypertension. Older patients with Down syndrome are at higher risk for having mitral valve insufficiency, even if they haven’t had problems at a younger age. The presence of a murmur should be sought.
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Atlantoaxial instability due to ligamentous laxity between the C1 atlas and C2 axis, resulting in excessive movement and subluxation, can lead to spinal cord compression. About 2% of patients will have cord compression, producing symptoms such as easy fatigability, difficulty walking, abnormal gait, decreased neck mobility, motor weakness, and sensory deficits. About 20% will have asymptomatic C1-C2 subluxation. The presence of atlantoaxial subluxation is readily diagnosed with lateral radiographs of the cervical spine in flexion, extension, and neutral positions. However, radiographic films of the cervical spine are not routinely done because the incidence of symptomatic atlantoaxial instability is rare, and these films are of “potential but unproven value“ in detecting those at risk for spinal injury, according to a publication by the American Academy of Pediatrics in 1995.
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