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Spondyloepiphyseal dysplasia congenita with ventilator dependence: Two case reports
1201
Spondyloepiphyseal Dysplasia Congenita With Ventilator Dependence: Two Case Reports Kimberly B. Augenstein,
MD, Michael J. Ward, MD, Virginia S. Nelson, MD
ABSTRACT. Augenstein KB, Ward MJ, Nelson VS. Spondyloepiphyseal dysplasia congenita with ventilator dependence: two case reports. Arch Phys Med Rehabil 1996; 77: 1201-4. Home mechanical ventilation has recently become feasible in a number of conditions. Several small series and case reports mention respiratory insufficiency or failure in a subset of patients with spondyloepiphyseal dysplasia congenita. Two cases of successful home mechanical ventilation in children, now 7 years of age, who have spondyloepiphyseal dysplasia congenita and respiratory insufficiency, are reported. Novel rehabilitation planning has facilitated the growth and development of these children. 0 I996 by the American Congress of Rehabilitation Medicine and the American Academy of Physical Medicine and Rehabilitation
S
PONDYLOEPIPHYSEAL dysplasia refers to a group of bone dyplasias with primary and progressive abnormalities of the epiphyses and spine resulting in short-trunked dwarfism. Spondyloepiphyseal dysplasia congenita (SEDC) was first described by Spranger in 1966 and further characterized in 1970 as a “heritable dysplasia manifested at birth with smallness of stature and retarded ossification of the vertebral bodies, pelvis and extremities.“’ Other clinical manifestations include barrelshaped chest, flat facies, cleft palate, clubfoot, muscular hypotonia, and may include sensorineural deafness.‘.” Transmission is considered autosomal dominant with most cases caused by spontaneous mutation.‘.” In childhood the vertebral bodies become flattened and irregular, resulting in kyphoscoliosis. Other changes include odontoid hypoplasia, rhizomelic limb shortening, pelvic dysplasia, and retarded ossification of the femoral heads with coxa vara.‘.’ Secondary complications result, including delayed motor development,2 atlantoaxial instability (35% to 50%),‘,4 recurrent otitis media,> myopia and retinal detachment.2-4premature arthritis, and lumbosacral lordosis with waddling gait.‘.’ A primary defect in type II collagen has been implicated’; this is the predominant collagen of cartilage, intervertebral disc, and vitreous.’ Respiratory complications have been described less often. Naumoff’ reported one male with respiratory difficulties from birth who died at 36 hours of age; postmortem examination showed a small chest, pulmonary hypoplasia, and bronchopneumonia. Murray et aI4 described a male with respiratory distress at birth and recurrent cyanosis who died at 5 months of age. Macpherson and Wood’ described 7 children with respiratory From the Department of Physical Medicine and Rehabililarion, Univrrsiry of Michigan Medical Canter, Ann Arbor. Submitted for puhlicarion November 9. 199.5. Accepted in revised form February 16, 1996. No commercial pany having a direct or indirect inkrcsl in the subject matter of this ankle has or will confer a bcnclil upon the authors or upon any organization with which the authors ore associated. Rcprinl requests to Kimberly B. Augenstcin. MD. Department of Physical Medicine and Rehabilitation. llniversity of Michigan Medical Center. I.500 E. Medical Cenrer Drive. Ann Arbor. MI 48 lo!). 0 1996 by the American Congress of Rchabilirarion Medicine and the American Academy of Physical Medicine and Rchabilifation 0003~9993fl6/771 I-376lS3.WfJ
distress at birth, 6 of whom died between 3 hours and 5 days; however, Harding et al’ suggested that 2 of these cases were most likely hypochondrogenesis. Hull and Barnes’” reported a child with difficulties at birth who at 14 months had respiratory function that was “limited but adequate.” Only Harding et al’ have discussed ventilatory management of infants with SEDC and respiratory distress: in 3 of 11 children evaluated in their clinic, tracheostomy was required, with 2 needing continuous positive airway pressure(CPAP) “to maintain airway patency.” They concluded, “We expect gradual improvement of the tracheobronchomalacia, secondary to both growth of the airway and maturation of the tracheal cartilages. Therefore, we remain optimistic that eventually discontinuation of CPAP and decannulation will be feasible in all three children.“’ We follow two children with SEDC in the Pediatric Home Ventilator Clinic who at age 7 do not show significant tracheobronchomalacia and continue to require mechanical ventilatory support. This has profound implications for the development and rehabilitation of these children. CASE
REPORTS
case1
This 7-year-old girl was born full term after an uncomplicated pregnancy with prenatal diagnosis of a short stature syndrome. Delivery was by Cesarean section after failed vacuum and forceps attempt. Birthweight was 51b 1202. She required immediate intubation with Apgars I and 5 at 1 and 5 minutes. Skeletal survey at age 2 days was consistent with SEDC: oval shaped vertebral bodies with odontoid hypoplasia, short broad thorax, shortened broad long bones, flattened acetabulum, delayed ossification of symphysis pubis and growth centers of the knee and ankle. Chest films throughout her neonatal intensive care unit (NICU) course continued to show small thorax with clear lungs and intermittent basilar atelectasis. During her 4-month NICU course she failed multiple attempts to wean from the ventilator. Eventually tracheostomy was performed. Posterior tibia1 somatosensory evoked potentials (SSEPs)showed absenceof high thoracic spine and scalp potentials. Brain stem auditory evoked response (BAER) screening was failed. At 6 months she was discharged home from the pediatric inpatient rehabilitation service on a Sechrist ventilator in intermittent mandatory ventilation (IMV) mode with positive endexpiratory pressure (PEEP) 8. An Aberdeen tracheostomy tube with swivel adaptor allowed stable tubing attachment on her short neck. A specialized prone board accommodated the ventilator and tubing. She maintained better upper extremity movement than lower with sustained bilateral ankle clonus and general hypotonia. No progression of myelopathy was noted. Secondary to oral aversion she was maintained with nasogastric feedings. An ethafoam car seat was fashioned to support her disproportionate head. By 18 months she had been readmitted twice, once with mucous plugging and once with pneumonia. At 18 months the Sechristventilator was replaced by the LP-6 to improve mobility and portability as well as to eliminate air compressors. For Arch
Phys
Mod
Reha&il
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November
1996
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mobility she was fitted with a manual wheelchair with ventilator tray. By 2 years she could tolerate 1 hour off the ventilator. Secondary to reactive airway disease bronchodilators were added to the treatment regimen. Bronchoscopy demonstrated only mild tracheomalacia. A gastrostomy tube was placed for feeding. Development of head control and sitting balance was facilitated by use of a comer chair; by 30 months she began rolling, sitting without support, and scooting. Language remained significantly delayed with no oral speech and 4 gestures. By 3 years cervical bracing was briefly tried elsewhere without clinical change. Magnetic resonance imaging (MRI) showed no cervical stenosis or compression in flexion/extension views although ventriculomegaly with increased subarachnoid space was noted. SSEPscontinued to show a stable conduction delay with no changes with flexion or extension. Neurological examination results continued to demonstrate bilateral ankle clonus, but otherwise normal reflexes. Audiogram showed severe sensorineural hearing loss necessitating bilateral hearing aides. Sleep study demonstrated only mild hypopnea and occasional mild obstructional apnea (4 per study) with no change in pattern on or off the ventilator. She tolerated 4 to 5 hours off the ventilator. Mild tracheomalacia was again noted on bronchoscopy. At this time she underwent surgery for cleft palate repair, ear tubes, and lacrimal duct cammlation. Developmentally, after serial casting and fitting with ankle-foot orthoses, she began using a standing frame. School evaluation revealed cognitive age equivalent 13 to 18 months, social 23 to 30 months, receptive language 9 to 11 months, fine motor 15 to 18 months, and gross motor 6 to 9 months. Growth at this time was 1 SD above the mean for children with SEDC (weight 21Slb, length 28.5 inches).’ ’ By age 5 she required intermittent courses of oral steroids at home for asthma and had one admission for viral pneumonia. Time off the ventilator increased to 4 hours twice daily. She underwent bilateral hip reduction for hip dysplasia. Developmentally she was cruising and walking with a reverse walker with hip support; language development remained markedly delayed with an expressive vocabulary of 7 signs. Mobility improved markedly with use of a power wheelchair with ventilator tray. At age 7 neurological examination results remained stable. Median nerve SSEPs showed normal peak latencies at Erb’s point (EP), N13, and N20. Interpeak latencies of EP to N13 were normal, N13 to P13 were prolonged. No changes were noted with flexiotiextension; posterior tibia1 SSEPs could not be obtained. MRI of the spine showed severe platyspondyly with bulging discs and cervical kyphosis centered at C3 with a minimally flattened cord; no signal aberration was present in the cord. The hypoplastic dens was tightly opposed to the anterior arch of C 1. Chest radiograph showed only chronic peribronchial cuffing. She continued to require 16 to 18 hours per day ventilatory support with SIMV 14, tidal volume 2OOccand 0.5 liter oxygen; this requirement increased with minor illnesses. In clinic, end-tidal carbon dioxide was 40 with ventilator support and 37 without; respiratory rate increased off the ventilator. Tracheostomy tube was a 4.5 Portex Aberdeen. She ate orally with fluids supplemented by gastrostomy tube. Developmentally she walked independently short distances and was independent with power mobility for longer distances. She maintained bowel continence and daytime bladder continence with timed voids. After her first year in a classroom for the hearing-impaired, expressive vocabulary was approximately 30 signs and a few recognizable words. Weight was 28lb, length 30.5 inches (-1 SD), head circumference 52.8cm, chest circumference 58cm. Arch
Phye Med
Rehabil
Vol77,
November
1996
DYSPLASIA,
Augenetein
Case 2 This 7-year-old boy was diagnosed with a short stature syndrome on prenatal ultrasound. He was born prematurely at 33 weeks estimated gestational age with birthweight 41b loz. He was intubated at birth and mechanically ventilated for 18 hours with eventual discharge home on oxygen via nasal cannula. Diagnosis of SEDC was made at another institution. At age 5 months he required reintubation with subsequent tracheostomy placement at 8 months. He remained hospitalized from age 5 months to 24 months at which time he was discharged with a Sechrist ventilator, oxygen, tracheostomy, and gastrostomy tube. He continued to have frequent hospitalizations for pneumonia until the age of 3 years, as well as recurrent otitis media necessitating ear tubes. At age 3 he was weaned to 4cm CPAP and 25% oxygen (from 60%). Language skills were noted to be ageappropriate. Between age 3 and 5 he had only one hospitalization for respiratory insufficiency. He was diagnosed with hearing loss and provided with hearing aids at age 4. At age 5 when he was first seen in the University of Michigan Home Ventilator Clinic he was using a Sechrist ventilator with CPAP during the night and tracheostomy mask oxygen during the day. He was changed to Bipap for greater portability and to eliminate air compressors. Bronchoscopy performed elsewhere at age 5 and 6 was unremarkable, chest radiograph was clear, and cardiac examination results were normal. Growth parameters were weight 27lb, length 30 inches (- 1 SD),” head circumference 54.5cm, and arm span 8Ocm. At age 7 he was doing well on inspiratory positive airway pressure (IPAP) 8/expiratory positive airway pressure (EPAP) 4 during the night and 24% oxygen via Ventimask during the day. Room air saturations were 88% to 91%. Tracheostomy was a no. 2 pediatric Shiley. All nutrition was oral. After repair of bilateral hip dislocation he was able to ambulate short distances independently and household distances with reverse walker; however, he was not able to manage his own oxygen tank. He used a manual wheelchair with oxygen holder which he could propel short distances. He was enrolled in a Physically or Otherwise Health Impaired (POHI) school program and had recently been started on methylphenidate for attention deficit disorder. DISCUSSION Harding et al9 reviewed five possible mechanisms for respiratory problems in SEDC: (1) small thorax with decreasedintrathoracic volume, (2) abnormal chest wall compliance, (3) horizontal rib alignment resulting in decreased tidal volume, (4) tracheomalacia, and (5) cervical spine instability with compression of the medulla and/or upper cervical cord. Myer and Cotton” also reported laryngotracheal stenosisin two patients with an unclassified form of spondyloepiphyseal dysplasia. Respiratory complications associated with conditions of a small thorax were first reported by Hull and Barnes” in 1971; they described respiratory insufficiency characterized by rapid shallow breathing associatedwith “limited rib growth” in several conditions including SEDC, thoracic dystrophy, diastrophic dwarfism, Ellis-Van Creveld, thanatophoric dwarfism, and achondroplasia. Although diverse conditions, these have in common a small thorax with horizontal rib alignment. Achrondoplasia, as the most common, has also received the most study. Stokes and colleagues” reported a series of 9 patients with achondoplasia and respiratory complications, 6 of whom were considered symptomatic. All 6 infants demonstrated hypoxemia
SPONDVLOEPIPHVSEAL
without significant hypercapnia, leading the authors to hypothesize that the abnormally shaped rib cage either reduced chest wall recoil or interfered with normal intercostal muscle function resulting in decreased functional residual capacity. “The reduced functional residual capacity, coupled with the low elastic recoil and supine position of infancy, was sufficient to cause airway closure, atelectasis. and hypoxemia, but not alveolar hypoventilation.” They later studied a population of children, adolescents, and adults with achondroplasia, demonstrating a 25% to 30% reduction in expected vital capacity, even when adjusted for sitting height.“’ Both of the children with SEDC we describe also have respiratory patterns characterized by tachypnea and hypoxemia without hypercapnia. These findings are consistent with those of Stokes in achondroplasia. suggesting a mechanism related to reduced vital capacity. An abnormality in type II collagen could be expected to result in abnormalities of the tracheobronchial cartilage, possibly resulting in the tracheomalacia found in the series of Harding et al” Tracheobronchomalacia, however, was not a significant finding in our patients. The last mechanism mentioned by Harding et al, ie, cervical spine instability with cord or medullary compression, has been questioned in patient I secondary to abnormal SSEP findings and ankle clonus. These findings have been stable throughout her course while her gross motor development, although delayed, has steadily progressed. Neurological examination results other than ankle clonus have remained within normal limits. Sleep study performed at age 3 failed to demonstrate central apnea or significant obstructive apnea. Nelson and coworkers” studied 23 adults and children with achondroplasia and found abnormal SSEPsin 7 patients with abnormal neurological examination results (including mild abnormalities) and 7 (44%) of I6 patients without symptoms. In a second study by Nelson,‘” 7 of 32 patients with achondroplasia had abnormal sleep studies, all with abnormal SSEPs;6 had significant obstructive apnea, and I had hypoxemia without apnea. Of those without respiratory symptoms, 76% also had abnormal SSEPs,suggesting high sensitivity but low specificity of SSEPsin predicting respiratory abnormalities. Contrary to this, Waters and coworkers found a low sensitivity for posterior tibia1 SSEPsin predicting respiratory symptoms in 20 children and young adults with achondroplasia. Of 20 unselected patients, all had abnormal sleep studies defined as arousal, change in saturation greater than 3%. or pattern of repetitive apnea; 60% had central/mixed apnea and 35% had complete obstructive apnea. SSEPsdid not correlate with symptoms; SSEPswere classified as normal in 1I patients, delayed or poorly defined in 4, and absent cortical response in 4. Sensitivity and specificity may even be lower in SEDC, since the major cause of spinal cord compression associated with odontoid hypoplasia is ventral secondary to hypertrophy of the posterior longitudinal ligaments as opposed to the posterior compression seen secondary to stenosisat the foramen magnum in achondroplasia.” These two patients demonstrate successful home ventilation for respiratory insufficiency secondary to SEDC. Historically, medical care for children with SEDC has been provided by geneticists, pediatricians, orthopedists, and endocrinologists.‘* In case I, care has been provided primarily by a coordinated ventilator rehabilitation team including physiatry, pediatrics, pediatric pulmonary, otolaryngology, nursing, respiratory therapy, physical and occupational therapy, speech pathology, and parents, with consultation of other specialists. In case 2, most care has been provided at a community hospital with consultation from the physiatrist and pulmonologist associatedwith the home ventilator clinic. Both children have attended camp for ventilator-assisted
children
and
their
parents
have
attended
a support
DYSPLASIA,
1203
Augmstein
group. Issuesaddressedby the rehabilitation team have included portability
of ventilator
systems
to improve
mobility,
develop-
ment, and community integration; specialized seating and positioning to accomodate the large head, spine and hip deformities; bracesand modified walkers, serial casting, nutrition, and physical and occupational therapy to promote attainment of developmental milestones and prevention of joint complications. Mobility
allows
a
child
to
explore
the
environment,
develop
independence, and interact with peers. Toward this end, the LP6 and Bipap units were chosen for portability. With a power wheelchair and ventilator tray, patient I is now independent in community mobility. In SEDC, associated hearing impairment secondary to sensorineural deafness and recurrent otitis media can contribute an additional source of disability. Language delays can be related to hearing impairment and to tracheostomy.‘UEarly intervention by speech therapists, audiologists, and schools is appropriate. Early in her course, patient I “passed” behavioral hearing screen despite a failed BAER in infancy. Hearing aids were provided at age 3 when formal hearing testing demonstrated sensorineural hearing loss. School services for the hearing impaired were difficult to obtain secondary to the primary educational classification of Physically or Otherwise Health Impaired. Advocacy on the part of parents and professionals is important in obtaining full and appropriate services. Rehabilitation professionals provide a unique perspective on aging with childhood-onset disability. ln SEDC, life expectancy and cognitive development are expected to be normal.’ Monitoring of respiratory, neurological, eye, and orthopedic complications, therapeutic exercisesto prevent joint complications, adaptive equipment to aid in mobility and activities of daily living, and school and vocational counseling are important to maintaining quality of life and promoting age-appropriate skills. Collaborative researchefforts may better define modalities of monitoring and treating complications. In contrast to Harding et al,9 we have found that mechanical ventilation may be required long-term and can play a vital role in the growth and development of these patients. References
SprangerJW. LangerLO. Spondyloepiphyseat dysplasiacongenita. Radiology 1970;94:313-22. ScottCl. Dwarfism.Ciba-GeigyClinicalSymposia1988;40:l-32. SprangerJW.Spondyloepiphyseal dysplasiacongenita.In: Bergsma D. editor. Skeletaldysplasias.Miami: SymposiaSpecialists,1974. Murray TG. GreenWR, MaumeneeIH. Kopits SE. Spondylcepiphysealdysplasiacongenita:light and electronmicroscopicstudies of the eye. Arch Ophthalmol 1985;103:407-lI. Goldberg MJ. Orthopedic aspects of hone dysplasias. Orthop Clin North Am 1976: 7445-56. Shyer L, editor. Biochemistry. New York: W.H. Freeman and Co, 1981. Naumoff P. Thoracic dysplasia in spondylocpiphyseal dysplasia congenita. Am J Dis Child 1977; 131:653-4.
MacphersonRI, Wood BP. Spondyloepiphysealdysplasiacon9.
IO. II.
12. 13.
genita: a cause of lethal neonatal dwarfism. Pediatr Radio] 1980:9: 2 17-24. Harding CO, Green CG, Perloff WH, Pauli RM. Respiratory complications in children with spondyloepiphyscal dysplasia congenita. Pediatr Pulmonol 1990; 9:49-54. Hull D, Barnes ND. Children with small chests. Arch Dis Childhood 1972;47:12-18. Horton WA, Hall JG, Scott Cl, Pyeritz RE, Rimoin DL. Growth curves for height for diastrophic dysplasia. spondylocpiphyseal dysplasia congenita, and psucdoachondroplasia. Am J Dis Child 1982; 136:316-9. Myer CM, Cotton RT. Laryngotracheal stenosis in spondyloepiphyseal dysplasia. Laryngoscope 1985;95:3-5. Stokes DC. Phillips JA, Leonard CO, Dorst JP, Kopits SE, Trojak
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Mod
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SE, et al. Respiratory complications of achondroplasia. J Pediatr 1983; 102:534-41. 14. Stokes DC, Pyeritz RE, Wise RA, Fairlough D, Murphy EA. Spirometry and chest wall dimensions in achondroplasia. Chest 1988; 93:364-9. 15. Nelson FW, Goldie WD, Hecht JT, Butler IJ, Scott CL Short-latency somatosensory evoked potentials in the management of patients with achondroplasia. Neurology 1984;34: 1053-g. 16. Nelson FW, Hecht JT, Horton WA, Butler JJ, Goldie WD, Miner
Arch
Phys Med
Rehabil
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1996
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Augenstein
M. Neurological basis of respiratory complications in achondroplasia. Ann Neural 1988;24:89-93. 17. Waters KA, Everett F, Sillence D, Fagan E, Sullivan CE. Breathing abnormalities in sleep in achondroplasia. Arch Dis Child 1993;69: 191-6. 18. Wardner JM, Nelson VS. Short-stature conditions: role of rehabilitation professionals. Rehabil Report 1988;4:1-5. 19. Aradine CR. Young children with long-term tracheostomies: health and development. West J Nurs Res 1983;5:115-27.
Spondyloepiphyseal Dysplasia Congenita With Ventilator Dependence: Two Case Reports Kimberly B. Augenstein,
MD, Michael J. Ward, MD, Virginia S. Nelson, MD
ABSTRACT. Augenstein KB, Ward MJ, Nelson VS. Spondyloepiphyseal dysplasia congenita with ventilator dependence: two case reports. Arch Phys Med Rehabil 1996; 77: 1201-4. Home mechanical ventilation has recently become feasible in a number of conditions. Several small series and case reports mention respiratory insufficiency or failure in a subset of patients with spondyloepiphyseal dysplasia congenita. Two cases of successful home mechanical ventilation in children, now 7 years of age, who have spondyloepiphyseal dysplasia congenita and respiratory insufficiency, are reported. Novel rehabilitation planning has facilitated the growth and development of these children. 0 I996 by the American Congress of Rehabilitation Medicine and the American Academy of Physical Medicine and Rehabilitation
S
PONDYLOEPIPHYSEAL dysplasia refers to a group of bone dyplasias with primary and progressive abnormalities of the epiphyses and spine resulting in short-trunked dwarfism. Spondyloepiphyseal dysplasia congenita (SEDC) was first described by Spranger in 1966 and further characterized in 1970 as a “heritable dysplasia manifested at birth with smallness of stature and retarded ossification of the vertebral bodies, pelvis and extremities.“’ Other clinical manifestations include barrelshaped chest, flat facies, cleft palate, clubfoot, muscular hypotonia, and may include sensorineural deafness.‘.” Transmission is considered autosomal dominant with most cases caused by spontaneous mutation.‘.” In childhood the vertebral bodies become flattened and irregular, resulting in kyphoscoliosis. Other changes include odontoid hypoplasia, rhizomelic limb shortening, pelvic dysplasia, and retarded ossification of the femoral heads with coxa vara.‘.’ Secondary complications result, including delayed motor development,2 atlantoaxial instability (35% to 50%),‘,4 recurrent otitis media,> myopia and retinal detachment.2-4premature arthritis, and lumbosacral lordosis with waddling gait.‘.’ A primary defect in type II collagen has been implicated’; this is the predominant collagen of cartilage, intervertebral disc, and vitreous.’ Respiratory complications have been described less often. Naumoff’ reported one male with respiratory difficulties from birth who died at 36 hours of age; postmortem examination showed a small chest, pulmonary hypoplasia, and bronchopneumonia. Murray et aI4 described a male with respiratory distress at birth and recurrent cyanosis who died at 5 months of age. Macpherson and Wood’ described 7 children with respiratory From the Department of Physical Medicine and Rehabililarion, Univrrsiry of Michigan Medical Canter, Ann Arbor. Submitted for puhlicarion November 9. 199.5. Accepted in revised form February 16, 1996. No commercial pany having a direct or indirect inkrcsl in the subject matter of this ankle has or will confer a bcnclil upon the authors or upon any organization with which the authors ore associated. Rcprinl requests to Kimberly B. Augenstcin. MD. Department of Physical Medicine and Rehabilitation. llniversity of Michigan Medical Center. I.500 E. Medical Cenrer Drive. Ann Arbor. MI 48 lo!). 0 1996 by the American Congress of Rchabilirarion Medicine and the American Academy of Physical Medicine and Rchabilifation 0003~9993fl6/771 I-376lS3.WfJ
distress at birth, 6 of whom died between 3 hours and 5 days; however, Harding et al’ suggested that 2 of these cases were most likely hypochondrogenesis. Hull and Barnes’” reported a child with difficulties at birth who at 14 months had respiratory function that was “limited but adequate.” Only Harding et al’ have discussed ventilatory management of infants with SEDC and respiratory distress: in 3 of 11 children evaluated in their clinic, tracheostomy was required, with 2 needing continuous positive airway pressure(CPAP) “to maintain airway patency.” They concluded, “We expect gradual improvement of the tracheobronchomalacia, secondary to both growth of the airway and maturation of the tracheal cartilages. Therefore, we remain optimistic that eventually discontinuation of CPAP and decannulation will be feasible in all three children.“’ We follow two children with SEDC in the Pediatric Home Ventilator Clinic who at age 7 do not show significant tracheobronchomalacia and continue to require mechanical ventilatory support. This has profound implications for the development and rehabilitation of these children. CASE
REPORTS
case1
This 7-year-old girl was born full term after an uncomplicated pregnancy with prenatal diagnosis of a short stature syndrome. Delivery was by Cesarean section after failed vacuum and forceps attempt. Birthweight was 51b 1202. She required immediate intubation with Apgars I and 5 at 1 and 5 minutes. Skeletal survey at age 2 days was consistent with SEDC: oval shaped vertebral bodies with odontoid hypoplasia, short broad thorax, shortened broad long bones, flattened acetabulum, delayed ossification of symphysis pubis and growth centers of the knee and ankle. Chest films throughout her neonatal intensive care unit (NICU) course continued to show small thorax with clear lungs and intermittent basilar atelectasis. During her 4-month NICU course she failed multiple attempts to wean from the ventilator. Eventually tracheostomy was performed. Posterior tibia1 somatosensory evoked potentials (SSEPs)showed absenceof high thoracic spine and scalp potentials. Brain stem auditory evoked response (BAER) screening was failed. At 6 months she was discharged home from the pediatric inpatient rehabilitation service on a Sechrist ventilator in intermittent mandatory ventilation (IMV) mode with positive endexpiratory pressure (PEEP) 8. An Aberdeen tracheostomy tube with swivel adaptor allowed stable tubing attachment on her short neck. A specialized prone board accommodated the ventilator and tubing. She maintained better upper extremity movement than lower with sustained bilateral ankle clonus and general hypotonia. No progression of myelopathy was noted. Secondary to oral aversion she was maintained with nasogastric feedings. An ethafoam car seat was fashioned to support her disproportionate head. By 18 months she had been readmitted twice, once with mucous plugging and once with pneumonia. At 18 months the Sechristventilator was replaced by the LP-6 to improve mobility and portability as well as to eliminate air compressors. For Arch
Phys
Mod
Reha&il
Vol77,
November
1996
1202
SPONDYLOEPIPHYSEAL
mobility she was fitted with a manual wheelchair with ventilator tray. By 2 years she could tolerate 1 hour off the ventilator. Secondary to reactive airway disease bronchodilators were added to the treatment regimen. Bronchoscopy demonstrated only mild tracheomalacia. A gastrostomy tube was placed for feeding. Development of head control and sitting balance was facilitated by use of a comer chair; by 30 months she began rolling, sitting without support, and scooting. Language remained significantly delayed with no oral speech and 4 gestures. By 3 years cervical bracing was briefly tried elsewhere without clinical change. Magnetic resonance imaging (MRI) showed no cervical stenosis or compression in flexion/extension views although ventriculomegaly with increased subarachnoid space was noted. SSEPscontinued to show a stable conduction delay with no changes with flexion or extension. Neurological examination results continued to demonstrate bilateral ankle clonus, but otherwise normal reflexes. Audiogram showed severe sensorineural hearing loss necessitating bilateral hearing aides. Sleep study demonstrated only mild hypopnea and occasional mild obstructional apnea (4 per study) with no change in pattern on or off the ventilator. She tolerated 4 to 5 hours off the ventilator. Mild tracheomalacia was again noted on bronchoscopy. At this time she underwent surgery for cleft palate repair, ear tubes, and lacrimal duct cammlation. Developmentally, after serial casting and fitting with ankle-foot orthoses, she began using a standing frame. School evaluation revealed cognitive age equivalent 13 to 18 months, social 23 to 30 months, receptive language 9 to 11 months, fine motor 15 to 18 months, and gross motor 6 to 9 months. Growth at this time was 1 SD above the mean for children with SEDC (weight 21Slb, length 28.5 inches).’ ’ By age 5 she required intermittent courses of oral steroids at home for asthma and had one admission for viral pneumonia. Time off the ventilator increased to 4 hours twice daily. She underwent bilateral hip reduction for hip dysplasia. Developmentally she was cruising and walking with a reverse walker with hip support; language development remained markedly delayed with an expressive vocabulary of 7 signs. Mobility improved markedly with use of a power wheelchair with ventilator tray. At age 7 neurological examination results remained stable. Median nerve SSEPs showed normal peak latencies at Erb’s point (EP), N13, and N20. Interpeak latencies of EP to N13 were normal, N13 to P13 were prolonged. No changes were noted with flexiotiextension; posterior tibia1 SSEPs could not be obtained. MRI of the spine showed severe platyspondyly with bulging discs and cervical kyphosis centered at C3 with a minimally flattened cord; no signal aberration was present in the cord. The hypoplastic dens was tightly opposed to the anterior arch of C 1. Chest radiograph showed only chronic peribronchial cuffing. She continued to require 16 to 18 hours per day ventilatory support with SIMV 14, tidal volume 2OOccand 0.5 liter oxygen; this requirement increased with minor illnesses. In clinic, end-tidal carbon dioxide was 40 with ventilator support and 37 without; respiratory rate increased off the ventilator. Tracheostomy tube was a 4.5 Portex Aberdeen. She ate orally with fluids supplemented by gastrostomy tube. Developmentally she walked independently short distances and was independent with power mobility for longer distances. She maintained bowel continence and daytime bladder continence with timed voids. After her first year in a classroom for the hearing-impaired, expressive vocabulary was approximately 30 signs and a few recognizable words. Weight was 28lb, length 30.5 inches (-1 SD), head circumference 52.8cm, chest circumference 58cm. Arch
Phye Med
Rehabil
Vol77,
November
1996
DYSPLASIA,
Augenetein
Case 2 This 7-year-old boy was diagnosed with a short stature syndrome on prenatal ultrasound. He was born prematurely at 33 weeks estimated gestational age with birthweight 41b loz. He was intubated at birth and mechanically ventilated for 18 hours with eventual discharge home on oxygen via nasal cannula. Diagnosis of SEDC was made at another institution. At age 5 months he required reintubation with subsequent tracheostomy placement at 8 months. He remained hospitalized from age 5 months to 24 months at which time he was discharged with a Sechrist ventilator, oxygen, tracheostomy, and gastrostomy tube. He continued to have frequent hospitalizations for pneumonia until the age of 3 years, as well as recurrent otitis media necessitating ear tubes. At age 3 he was weaned to 4cm CPAP and 25% oxygen (from 60%). Language skills were noted to be ageappropriate. Between age 3 and 5 he had only one hospitalization for respiratory insufficiency. He was diagnosed with hearing loss and provided with hearing aids at age 4. At age 5 when he was first seen in the University of Michigan Home Ventilator Clinic he was using a Sechrist ventilator with CPAP during the night and tracheostomy mask oxygen during the day. He was changed to Bipap for greater portability and to eliminate air compressors. Bronchoscopy performed elsewhere at age 5 and 6 was unremarkable, chest radiograph was clear, and cardiac examination results were normal. Growth parameters were weight 27lb, length 30 inches (- 1 SD),” head circumference 54.5cm, and arm span 8Ocm. At age 7 he was doing well on inspiratory positive airway pressure (IPAP) 8/expiratory positive airway pressure (EPAP) 4 during the night and 24% oxygen via Ventimask during the day. Room air saturations were 88% to 91%. Tracheostomy was a no. 2 pediatric Shiley. All nutrition was oral. After repair of bilateral hip dislocation he was able to ambulate short distances independently and household distances with reverse walker; however, he was not able to manage his own oxygen tank. He used a manual wheelchair with oxygen holder which he could propel short distances. He was enrolled in a Physically or Otherwise Health Impaired (POHI) school program and had recently been started on methylphenidate for attention deficit disorder. DISCUSSION Harding et al9 reviewed five possible mechanisms for respiratory problems in SEDC: (1) small thorax with decreasedintrathoracic volume, (2) abnormal chest wall compliance, (3) horizontal rib alignment resulting in decreased tidal volume, (4) tracheomalacia, and (5) cervical spine instability with compression of the medulla and/or upper cervical cord. Myer and Cotton” also reported laryngotracheal stenosisin two patients with an unclassified form of spondyloepiphyseal dysplasia. Respiratory complications associated with conditions of a small thorax were first reported by Hull and Barnes” in 1971; they described respiratory insufficiency characterized by rapid shallow breathing associatedwith “limited rib growth” in several conditions including SEDC, thoracic dystrophy, diastrophic dwarfism, Ellis-Van Creveld, thanatophoric dwarfism, and achondroplasia. Although diverse conditions, these have in common a small thorax with horizontal rib alignment. Achrondoplasia, as the most common, has also received the most study. Stokes and colleagues” reported a series of 9 patients with achondoplasia and respiratory complications, 6 of whom were considered symptomatic. All 6 infants demonstrated hypoxemia
SPONDVLOEPIPHVSEAL
without significant hypercapnia, leading the authors to hypothesize that the abnormally shaped rib cage either reduced chest wall recoil or interfered with normal intercostal muscle function resulting in decreased functional residual capacity. “The reduced functional residual capacity, coupled with the low elastic recoil and supine position of infancy, was sufficient to cause airway closure, atelectasis. and hypoxemia, but not alveolar hypoventilation.” They later studied a population of children, adolescents, and adults with achondroplasia, demonstrating a 25% to 30% reduction in expected vital capacity, even when adjusted for sitting height.“’ Both of the children with SEDC we describe also have respiratory patterns characterized by tachypnea and hypoxemia without hypercapnia. These findings are consistent with those of Stokes in achondroplasia. suggesting a mechanism related to reduced vital capacity. An abnormality in type II collagen could be expected to result in abnormalities of the tracheobronchial cartilage, possibly resulting in the tracheomalacia found in the series of Harding et al” Tracheobronchomalacia, however, was not a significant finding in our patients. The last mechanism mentioned by Harding et al, ie, cervical spine instability with cord or medullary compression, has been questioned in patient I secondary to abnormal SSEP findings and ankle clonus. These findings have been stable throughout her course while her gross motor development, although delayed, has steadily progressed. Neurological examination results other than ankle clonus have remained within normal limits. Sleep study performed at age 3 failed to demonstrate central apnea or significant obstructive apnea. Nelson and coworkers” studied 23 adults and children with achondroplasia and found abnormal SSEPsin 7 patients with abnormal neurological examination results (including mild abnormalities) and 7 (44%) of I6 patients without symptoms. In a second study by Nelson,‘” 7 of 32 patients with achondroplasia had abnormal sleep studies, all with abnormal SSEPs;6 had significant obstructive apnea, and I had hypoxemia without apnea. Of those without respiratory symptoms, 76% also had abnormal SSEPs,suggesting high sensitivity but low specificity of SSEPsin predicting respiratory abnormalities. Contrary to this, Waters and coworkers found a low sensitivity for posterior tibia1 SSEPsin predicting respiratory symptoms in 20 children and young adults with achondroplasia. Of 20 unselected patients, all had abnormal sleep studies defined as arousal, change in saturation greater than 3%. or pattern of repetitive apnea; 60% had central/mixed apnea and 35% had complete obstructive apnea. SSEPsdid not correlate with symptoms; SSEPswere classified as normal in 1I patients, delayed or poorly defined in 4, and absent cortical response in 4. Sensitivity and specificity may even be lower in SEDC, since the major cause of spinal cord compression associated with odontoid hypoplasia is ventral secondary to hypertrophy of the posterior longitudinal ligaments as opposed to the posterior compression seen secondary to stenosisat the foramen magnum in achondroplasia.” These two patients demonstrate successful home ventilation for respiratory insufficiency secondary to SEDC. Historically, medical care for children with SEDC has been provided by geneticists, pediatricians, orthopedists, and endocrinologists.‘* In case I, care has been provided primarily by a coordinated ventilator rehabilitation team including physiatry, pediatrics, pediatric pulmonary, otolaryngology, nursing, respiratory therapy, physical and occupational therapy, speech pathology, and parents, with consultation of other specialists. In case 2, most care has been provided at a community hospital with consultation from the physiatrist and pulmonologist associatedwith the home ventilator clinic. Both children have attended camp for ventilator-assisted
children
and
their
parents
have
attended
a support
DYSPLASIA,
1203
Augmstein
group. Issuesaddressedby the rehabilitation team have included portability
of ventilator
systems
to improve
mobility,
develop-
ment, and community integration; specialized seating and positioning to accomodate the large head, spine and hip deformities; bracesand modified walkers, serial casting, nutrition, and physical and occupational therapy to promote attainment of developmental milestones and prevention of joint complications. Mobility
allows
a
child
to
explore
the
environment,
develop
independence, and interact with peers. Toward this end, the LP6 and Bipap units were chosen for portability. With a power wheelchair and ventilator tray, patient I is now independent in community mobility. In SEDC, associated hearing impairment secondary to sensorineural deafness and recurrent otitis media can contribute an additional source of disability. Language delays can be related to hearing impairment and to tracheostomy.‘UEarly intervention by speech therapists, audiologists, and schools is appropriate. Early in her course, patient I “passed” behavioral hearing screen despite a failed BAER in infancy. Hearing aids were provided at age 3 when formal hearing testing demonstrated sensorineural hearing loss. School services for the hearing impaired were difficult to obtain secondary to the primary educational classification of Physically or Otherwise Health Impaired. Advocacy on the part of parents and professionals is important in obtaining full and appropriate services. Rehabilitation professionals provide a unique perspective on aging with childhood-onset disability. ln SEDC, life expectancy and cognitive development are expected to be normal.’ Monitoring of respiratory, neurological, eye, and orthopedic complications, therapeutic exercisesto prevent joint complications, adaptive equipment to aid in mobility and activities of daily living, and school and vocational counseling are important to maintaining quality of life and promoting age-appropriate skills. Collaborative researchefforts may better define modalities of monitoring and treating complications. In contrast to Harding et al,9 we have found that mechanical ventilation may be required long-term and can play a vital role in the growth and development of these patients. References
SprangerJW. LangerLO. Spondyloepiphyseat dysplasiacongenita. Radiology 1970;94:313-22. ScottCl. Dwarfism.Ciba-GeigyClinicalSymposia1988;40:l-32. SprangerJW.Spondyloepiphyseal dysplasiacongenita.In: Bergsma D. editor. Skeletaldysplasias.Miami: SymposiaSpecialists,1974. Murray TG. GreenWR, MaumeneeIH. Kopits SE. Spondylcepiphysealdysplasiacongenita:light and electronmicroscopicstudies of the eye. Arch Ophthalmol 1985;103:407-lI. Goldberg MJ. Orthopedic aspects of hone dysplasias. Orthop Clin North Am 1976: 7445-56. Shyer L, editor. Biochemistry. New York: W.H. Freeman and Co, 1981. Naumoff P. Thoracic dysplasia in spondylocpiphyseal dysplasia congenita. Am J Dis Child 1977; 131:653-4.
MacphersonRI, Wood BP. Spondyloepiphysealdysplasiacon9.
IO. II.
12. 13.
genita: a cause of lethal neonatal dwarfism. Pediatr Radio] 1980:9: 2 17-24. Harding CO, Green CG, Perloff WH, Pauli RM. Respiratory complications in children with spondyloepiphyscal dysplasia congenita. Pediatr Pulmonol 1990; 9:49-54. Hull D, Barnes ND. Children with small chests. Arch Dis Childhood 1972;47:12-18. Horton WA, Hall JG, Scott Cl, Pyeritz RE, Rimoin DL. Growth curves for height for diastrophic dysplasia. spondylocpiphyseal dysplasia congenita, and psucdoachondroplasia. Am J Dis Child 1982; 136:316-9. Myer CM, Cotton RT. Laryngotracheal stenosis in spondyloepiphyseal dysplasia. Laryngoscope 1985;95:3-5. Stokes DC. Phillips JA, Leonard CO, Dorst JP, Kopits SE, Trojak
Arch
Phy
Mod
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SE, et al. Respiratory complications of achondroplasia. J Pediatr 1983; 102:534-41. 14. Stokes DC, Pyeritz RE, Wise RA, Fairlough D, Murphy EA. Spirometry and chest wall dimensions in achondroplasia. Chest 1988; 93:364-9. 15. Nelson FW, Goldie WD, Hecht JT, Butler IJ, Scott CL Short-latency somatosensory evoked potentials in the management of patients with achondroplasia. Neurology 1984;34: 1053-g. 16. Nelson FW, Hecht JT, Horton WA, Butler JJ, Goldie WD, Miner
Arch
Phys Med
Rehabil
Vol77,
November
1996
DYSPLASIA,
Augenstein
M. Neurological basis of respiratory complications in achondroplasia. Ann Neural 1988;24:89-93. 17. Waters KA, Everett F, Sillence D, Fagan E, Sullivan CE. Breathing abnormalities in sleep in achondroplasia. Arch Dis Child 1993;69: 191-6. 18. Wardner JM, Nelson VS. Short-stature conditions: role of rehabilitation professionals. Rehabil Report 1988;4:1-5. 19. Aradine CR. Young children with long-term tracheostomies: health and development. West J Nurs Res 1983;5:115-27.