Down Syndrome Abstract
of the Month:
Mar 2005
Causes of persistent obstructive sleep apnea despite previous tonsillectomy and adenoidectomy in children with Down syndrome as depicted on static and dynamic cine MRI.
Donnelly LF, Shott SR, LaRose CR, Chini BA, Amin RS.
AJR Am J Roentgenol. 2004 Jul;183(1):175-81.
Department of Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA.
Abstract:
OBJECTIVE: Our purpose was to evaluate the causes of persistent obstructive sleep apnea despite previous tonsillectomy and adenoidectomy in children with Down syndrome as depicted on cine MRI. MATERIALS AND METHODS: Cine MRI studies performed to evaluate persistent obstructive sleep apnea despite previous tonsillectomy and adenoidectomy were reviewed. MRI was performed under sedation and included cine MR images (fast gradient-echo) obtained in the midline sagittal plane and in the axial plane at the base of the tongue and T1-weighted spin-echo and fast spin-echo inversion recovery images in the axial and sagittal planes. Imaging parameters reviewed included static and dynamic diagnoses made, frequency of recurrence and diameter of tonsillar tissue, and tongue morphology. RESULTS: Twenty-seven patients were identified (mean age, 9.9 years). Diagnoses included glossoptosis in 17 patients (63%), hypopharyngeal collapse in six (22%), recurrent and enlarged adenoid tonsils in 17 (63%), enlarged lingual tonsils in eight (30%), and macroglossia in 20 (74%). Of the 20 patients with macroglossia, 11 (55%) had absence of the normal median sulcus and 12 (60%) had evidence of fatty infiltration of the tongue musculature. CONCLUSION: Persistent obstructive sleep apnea in children with Down syndrome who have undergone previous adenoidectomy and tonsillectomy has multiple causes. The most common causes include macroglossia, glossoptosis, recurrent enlargement of the adenoid tonsils, and enlarged lingual tonsils.
My comments:
Studies have shown that anywhere from 30 to 50% of children with DS who have had tonsillectomy and adenoidectomy for obstructive sleep apnea (OSA) develop persistent or recurrent OSA. This statistic points out how OSA in children with DS can be caused by several factors other than large tonsils and/or adenoids.Some terms you need to know: "Cine MRI" is the use of the MRI to record a series of sequential pictures, in effect creating a "movie" of the upper airway during sleep. "Glossoptosis" is the movement of the back part of the tongue so that the tongue causes intermittent blockage of the airway. "Hypopharyngeal collapse" is the intermittent closure of the part of the airway just below the back of the throat (pharynx). The "adenoid tonsils," or "adenoids" for short," are located in the nasal passages and cannot be seen by physical exam. The "lingual tonsils" are located on the very back of the tongue and can be seen in some people; these are smaller than the throat tonsils or the adenoids. "Macroglossia" means enlargement of the tongue.
For children with DS and persistent OSA, the cine MRI is the best way to identify the cause of the OSA, which in turn best indentifies the best surgical approach to remedy the OSA.
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