Downs Syndrome

Referrals to pulmonary physicians for polysomnography to evaluate snoring or the possibility of sleep apnea syndrome often evolve into a multidisciplinary clinical problem. We present a young woman with two congenital abnormalities (Marfan's syndrome and retrognathism) which both may affect her decreased exercise tolerance, daytime hypersomnolence, and fatigue. Polysomnography and pulmonary exercise testing documented improvement in her upper airway diameter and exercise capacity. Her improved sleep pattern and her understanding of her exercise performance limitations afforded her a new outlook on life.

There is a definite correlation between obstructive sleep apnea syndrome (OSAS) and obstructive upper airway anatomic abnormalities such as retrognathism. Standard cephalometric roentgenograms in addition to pulmonary function testing with close analysis of the flow volume loop have become invaluable tools in the evaluation of some patients with sleep apnea.[1] Several studies also have delineated the expected pulmonary function abnormalities in patients with Marfan's syndrome.[2,3] These patients are known to have pulmonary complications including restrictive ventilatory defects, bullous emphysema, and an increased frequency of pneumothorax.[4-6]

The following case illustrates the decrease in sleep disturbance and improvement of pulmonary function test results and exercise performance with the treatment of an obstructive airway by bimaxillary orthognathic corrective surgery in a patient with the Marfan's syndrome.

CASE REPORT

This 22-year-old woman was referred to our care for sleep apnea evaluation. She was on active duty with the US Navy, but she could not sleep peacefully in the short racks on shipboard. Her bunk mates also noted excessively loud snoring. She reported daytime hypersomnolence and fatigue. Her physical examination showed a marfanoid habitus which fulfilled 13 of 15 classic criteria for Marfan's syndrome. She had (1) tall, thin stature, (2) long, narrow facies, (3) arm span greater than height (71 vs 70 inches), (4) arachnodactyly, (4) Steinberg thumb sign and wrist sign, (6) umbilicus sign, (7) low upper-to-lower body segment ratio (0:9), (8) high metacarpal index (9.0 [normal, 8.4 or less]), (9) hyperextenable knees and elbows, (10) kyphoscoliosis (10 [degrees] in this patient)--no pectus excavatum, (11) pes planus, (12) high arched palate, and (13) mitral valve prolapse. She did not have aortic insufficiency or lens displacement. Oral examination revealed a class 2 malocclusion with vertical maxillary excess, a high arched palate, and mandibular retrognathism.

Her sleep study did not confirm sleep apnea (obstructive apnea index--3/h), but her observed symptom complex during the sleep testing included agitated sleep pattern, arousals when supine, and loud snoring. The upper airway obstruction was deemed to be caused by her mandibular retrognathism. Corrective orthognathic surgery included a maxillary Lefort I osteotomy with impaction and advancement and a mandibular bilateral sagittal split osteotomy with advancement (mandible advanced 12 mm and the maxilla advanced 8 mm) and placement of rigid fixation. The second surgical procedure was an advancement genioplasty and vertical augmentation with autologous bone graft from her right hip. The operation was done in two stages to avoid iatrogenic fracture or nonunion of the mandible. The genioplasty improved airway dimensions to a degree that hyoid suspension was not necessary in this case. The patient had relief of her nighttime symptom complex and resolution of daytime hypersomnolence. A postoperative cephalometric roentgenogram demonstrated significant improvement in her upper airway obstruction with an increase of the posterior air space from 7 to 15 mm (Fig 1 and 2). Preoperative and postoperative pulmonary function tests and stage 1 incremental pulmonary exercise testing are presented in Table 1.

DISCUSSION

Marfan's syndrome is a heritable disorder of connective tissue with clinically prominent abnormalities of the ocular, skeletal, and cardiovascular systems.[7] Although pneumothorax is a common finding in patients with Marfan's syndrome,[6] the reduced life expectancy usually results from cardiac complications such as aortic dilatation, dissection and rupture and involvement of the aortic and mitral valves.[8]

Patients with Marfan's syndrome in general show a restrictive pattern on pulmonary function testing. However, if corrected for sitting height as we did in this patient, only those subjects with Marfan's syndrome with severe thoracic cage abnormalities have a remarkable restrictive pattern.[2] Our patient had only a 10 [degrees] d scoliosis and yet showed marked reduction in lung volumes (especially those related to forced effort like the forced vital capacity). We performed preoperative and postoperative pulmonary function testing and exercise physiology to quantify the impact of her obstructive upper airway abnormality on her lung function (Table 1). With the surgical

correction, significant improvements in inspiratory and expiratory flow and maximum minute ventilation were seen on routine testing. Her exercise testing also showed marked improvement in maximum ventilation, oxygen consumption, and ability to sustain increased work without dyspnea.

The definitive diagnosis of OSAS requires a polysomnographic evaluation in a sleep disorder laboratory. The patient is monitored overnight during rapid eye movement (REM) sleep and all stages of non-REM sleep while parameters such as arterial oxygen saturation, ECG, EEG, and respiratory muscle excursions are continuously recorded. The frequency and degree of arterial oxygen desaturation, the frequency of episodes of apnea/hypopnea per hour of sleep (apnea/hypopnea index) and any cardiac arrhythmias are noted. Either or both an apnea/hypopnea index greater than 5 to 10 and oxygen desaturations below 85 percent are diagnostic of OSAS.[9,10] Even though this patient did not have classic obstructive sleep apnea, the surgical procedure relieved her snoring and agitated sleep pattern. She also noted that she could sleep without being propped up. This relieved some depressive symptoms which had developed as a result of her not being able to fit in with her Navy peers. On discharge from the Navy, her self-image improved. Later, she was married. Sleep testing has a recognized value in quantifying and correcting causes for decreased REM sleep including depression.

Cephalometric studies have been employed in the evaluation of craniomandibular and upper airway abnormalities in patients with OSAS.[1] Those patients whose cephalometric findings include a long mandibular plane-hyoid (MP-H) and narrow posterior air space have a greater risk for an elevated respiratory disturbance index.[1] Posture also has an effect on upper airway dimensions.[11] The supine posture, as opposed to erect, is associated with significant narrowing of the retropalatal airway in many patients with the sleep apnea-hypopnea syndrome.[11] The symptom complex of our patient was markedly increased when she assumed the supine position in a short bunk. Although mandibular retrognathism has been associated with a higher frequency of OSAS and corrective jaw surgery has been reported to relieve OSAS symptoms,[10] a causal relationship has not been established between OSAS and class 2 malocclusion.[12]

The management of OSAS varies from noninvasive supportive measures to more invasive surgical procedures; the latter usually results from unsuccessful attempts with conservative treatment. Medical management of OSAS consists of avoidance of drugs that have central nervous system depressant activity such as alcohol, sedatives, and antihistamines. Weight reduction also is encouraged in the obese. The use of continuous positive airway pressure provides virtual eradication of OSAS with improvement of sleep quality and alleviation of daytime hypersomnolence in 75 to 95 percent of cases.[13] The use of tricylic antidepressants, to decrease obstruction by decreasing REM sleep and increasing pharyngeal muscle tone, also has been advocated.[13] Supplemental oxygen therapy has been shown to help prevent pulmonary hypertension and adverse cardiac effects.

Surgical intervention consists of procedures such as tracheostomy, uvulopalatopharyngoplasty and osteotomies. The increasing widespread use of continuous positive airway pressure has markedly decreased the need for tracheostomy in this disorder. Tracheostomy usually is reserved for the critically ill patient after failure of other treatment modalities. Since tracheostomy abolishes sleep apnea, it remains the standard against which all other treatments are compared. Uvulopalatopharyngoplasty involves the resection of the posterior segment of the soft palate and excess tissue of the lateral pharyngeal wall. Tonsillectomy is an integral part of uvulopalatopharyngoplasty when tonsils are present, but adenoidectomy is to be avoided generally in conjunction with uvulopalatopharyngoplasty due to the problem of postoperative nasopharyngeal stenosis. Mandibular osteotomies usually consist of bilateral sagittal split osteotomies with advancement. Hyoid myotomy and suspension also has been a helpful adjunct to this procedure.[14] Lefort I maxillary osteotomy also may be used to create space in the posterior airway.

Preoperative and postoperative cephalometric roentgenograms are essential in the evaluation of these patients (Fig 1 and 2). Fluoroscopic and computed tomographic examination and measurement of pharyngeal volume by digitized magnetic resonance imaging of the upper airway, or all of these, can provide dramatic evidence of increased pharyngeal area and correspond well with cephalometrics of the posterior air space.[9,15,16] No matter which treatment modality is employed in the management of patients with OSAS or disturbed sleep architecture, repeated polysomnographic evaluations are required to document successful treatment.

This is the first reported occurrence of these two congenital abnormalities (Marfan's syndrome and retrognathism). It was important to separate the contribution of each to the patient's symptom complex to assess the value of the surgical correction. The upper airway obstruction secondary to retrognathism mimicked the symptom complex of sleep apnea. Correction of the upper airway obstruction resulted in the return of normal sleep architecture. Furthermore, the maxillofacial and mandibular advancement relieved the dyspnea that occurred with exercise and improved pulmonary mechanics.

REFERENCES

[1] Partinen M, Guilleminault C, Quera-Salva M, Jamieson A. Obstructive sleep apnea and cephalometric roentgenograms. Chest 1988; 93:1199-1204

[2] Streeten EA, Murphy EA, Pyeritz RE. Pulmonary function in the Marfan syndrome. Chest 1987; 91:408-12

[3] Fuleihan FJD, Suh SK, Shepard RH. Some aspects of pulmonary function in the Marfan syndrome. Bull Johns Hopkins Hosp 1963; 113:320-28

[4] Dwyer EM Jr, Troncalf F. Spontaneous pneumothorax and pulmonary disease in the Marfan syndrome. Ann Intern Med 1965; 62:1285-91

[5] Turner JA, Stanley NN. Fragile lung in the Marfan syndrome. Thorax 1976; 31:771-75

[6] Hall JR, Pyeritz RE, Dudgeon DL, Haller JA Jr. Pneumothorax in the Marfan syndrome: prevalence and therapy. Ann Thorac Surg 1984; 37:500-04

[7] Pyeritz RE, McKusick VA. Basic defects in the Marfan syndrome. N Engl J Med 1981; 305:1011-12

[8] Murdock JL, Walker BA, Halpern BL, Kuzma JW, McKusick VA. Life expectancy and causes of death in the Marfan syndrome. N Engl J Med 1972; 286:804-08

[9] Haponik EF, Smith PL, Bohlman ME, Allen RP, Goldman SM, Bleecker ER. Computerized tomography in obstructive sleep apnea. Am Rev Respir Dis 1983; 127:221-26

[10] Dierks E, Geller M, Roffwarg H, Johns D. Obstructive sleep apnea syndrome: correction by mandibular advancement. South Med J 1990; 83:390-94

[11] Yildirim N, Fitzpatrick KF, Whyte KF, Jalleh R, Wightman AJA, Douglas NJ. The effect of posture on upper airway dimensions in normal subjects and in patients with the sleep apnea/hypopnea syndrome. Am J Respir Dis 1991; 144:845-47

[12] Triplett WW, Lund BA, Westbrook PR, Olsen KD. Obstructive sleep apnea syndrome in patients with class II malocclusion. Mayo Clin Proc 1989; 64:644-52

[13] Smolley LA. How to help patients with obstructive sleep apnea. J Respir Dis 1990; 11:723-32

[14] Riley RW, Powell N, Guilleminault C. Current surgical concepts for treating obstructive sleep apnea syndrome. J Oral Maxillofac Surg 1987; 45:149-57

[15] Suratt PM, Dee P, Atkinson RL, Armstrong P, Wilhoit SC. Fluoroscopic and computed tomographic features of the pharyngeal airway in obstructive sleep apnea. Am Rev Respir Dis 1983; 127:487-92

[16] Abbey NC, Block AJ, Green D, Mancuso A, Hellard DW. Measurement of pharyngeal volume by digitized magnetic resonance imaging. Am Rev Respir Dis 1989; 140:717-23

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