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Education & Practice Online First, published on November 3, 2014 as 10.1136/archdischild-2014-306883 EPILOGUE
Recurrent acute life-threatening events in a child with achondroplasia Mohamed O E Babiker,1 Christopher Edwards,2 Philip Davies,2 Roddy O’Kane1,3 A 2-month-old boy with achondroplasia was brought to the emergency department following an apnoeic episode while in a car seat. He required minimal resuscitation but was noted to have significant hypercarbia on the blood gas. There was no history suggestive of an intercurrent respiratory infection. Systemic examination was normal apart from skeletal features of achondroplasia. While in hospital, he had further brief apnoeic episodes. Polysomnography demonstrated central and obstructive sleep apnoeas (Apnoea Hypopnoea Index (AHI) is used to quantify the number of apnoeas and
hypopnoeas scored per hour1 and was found to be significantly elevated at 26.3/h). Subsequent to this, spinal T2-weighted MRI scans (figure 1) were undertaken. In light of the abnormal MRI, the neurosurgical team was consulted and a procedure was planned. To allow time to grow and improve the chances of a successful operation, he received non-invasive ventilation (Bilevel Positive Airway Pressure (BiPAP)) at night. However, he had a further significant apnoeic episode. He underwent an urgent neurosurgical procedure. Figure 2 demonstrates the postoperative spinal T2-weighted MRI scans. QUESTIONS 1. What are the causes of recurrent apnoeas in children with achondroplasia? 2. What is the abnormality shown in figure 1? 3. What is the neurosurgical procedure undertaken?
Figure 1 Pre-operative sagittal T2-weighted image of posterior fossa and upper spine.
Figure 2 Post-operative sagittal T2-weighted image of posterior fossa and upper spine.
Babiker MOE, et al. Arch Dis Child Educ Pract Ed 2014;0:1. doi:10.1136/archdischild-2014-306883
1
Copyright Article author (or their employer) 2014. Produced by BMJ Publishing Group Ltd under licence.
Downloaded from http://ep.bmj.com/ on April 16, 2015 - Published by group.bmj.com
EPILOGUE 3
ANSWERS 1. Apnoea is usually multifactorial. In addition to central causes, such as cervicomedullary compression, mechanical causes include small thorax, narrow upper airways due to underdevelopment of the mid face and adenotonsillar hypertrophy. Risk of sudden death in achondroplastic children below 5 years was estimated in one study to be 50-fold higher than in the normal population.2 This has been linked to brainstem compression in over half of the cases.3 The American Academy of Paediatrics recommends baseline neuroimaging of all children with achondroplasia during infancy.4 Because of the narrow space around the brainstem and cervical cord along with a relatively large head, it has been recommended that the use of baby swings and carrying slings as well as rearward facing car seats should be avoided in these children.5 2. Figure 1 shows significant cord compression at the cervicomedullary junction. The anteroposterior diameter of the spinal canal at the craniocervical junction was 2.8 mm, more than two SDs below the mean measurement for achondroplasia.6 Children with achondroplasia are at increased risk of foramen magnum stenosis secondary to underdevelopment of the occiput.6 This case illustrates that cervicomedullary junction obstruction should be considered in any child with achondroplasia presenting with recurrent acute life-threatening events. 3. This patient underwent foramen magnum decompression to create extra space at the craniocervical junction as demonstrated in figure 2. Postoperative polysomnography demonstrated significant improvement in his ventilation (AHI 5.7/h). He no longer required BiPAP and continued to thrive well. Mohamed O E Babiker,1 Christopher Edwards,2 Philip Davies,2 Roddy O’Kane1,3 1
Fraser of Allander Neurosciences Unit, Royal Hospital for Sick Children, Glasgow, UK 2 Respiratory Department, Royal Hospital for Sick Children, Glasgow, UK
Neurosurgery Department, Institute of Neurosciences, Southern General Hospital, Glasgow, UK Correspondence to Dr Mohamed O E Babiker, Fraser of Allander Neurosciences Unit, Royal Hospital for Sick Children, Dalnair Street, Yorkhill, Glasgow G3 8SJ, UK; [email protected]
Contributors MOEB and CE wrote the provisional manuscript. PD revised the polysomnography data and edited the final draft and ROK reviewed the MRI images. All authors have contributed to the clinical management of this case. Competing interests None. Patient consent Obtained. Ethics approval Provenance and peer review Not commissioned; externally peer reviewed. To cite Babiker MOE, Edwards C, Davies P, et al. Arch Dis Child Educ Pract Ed Published Online First: [ please include Day Month Year] doi:10.1136/ archdischild-2014-306883 Received 31 May 2014 Accepted 8 October 2014
REFERENCES 1 Berry RB, Budhiraja R, Gottlieb DJ, et al. Rules for scoring respiratory events in sleep: update of the 2007 AASM Manual for the Scoring of Sleep and Associated Events. J Clin Sleep Med 2012;8:597–619. 2 Wynn J, King TM, Gambello MJ, et al. Mortality in achondroplasia study: a 42-year follow-up. Am J Med Genet A 2007;143A:2502–11. 3 Hecht JT, Francomano CA, Horton WA, et al. Mortality in achondroplasia. Am J Hum Genet 1987;41:454–64. 4 Trotter TL, Hall JG. Health supervision for children with achondroplasia. Pediatrics 2005;116:771–83. 5 Wright MJ, Irving MD. Clinical management of achondroplasia. Arch Dis Child 2012;97:129–34. 6 Hecht JT, Horton WA, Reid CS, et al. Growth of the foramen magnum in achondroplasia. Am J Med Genet 1989; 32:528–35.
Arch Dis Child Educ Pract Ed 2014;0:1. doi:10.1136/archdischild-2014-306883
1
Downloaded from http://ep.bmj.com/ on April 16, 2015 - Published by group.bmj.com
Recurrent acute life-threatening events in a child with achondroplasia Mohamed O E Babiker, Christopher Edwards, Philip Davies and Roddy O'Kane Arch Dis Child Educ Pract Ed published online November 3, 2014
Updated information and services can be found at: http://ep.bmj.com/content/early/2014/11/03/archdischild-2014-306883
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Education & Practice Online First, published on November 3, 2014 as 10.1136/archdischild-2014-306883 EPILOGUE
Recurrent acute life-threatening events in a child with achondroplasia Mohamed O E Babiker,1 Christopher Edwards,2 Philip Davies,2 Roddy O’Kane1,3 A 2-month-old boy with achondroplasia was brought to the emergency department following an apnoeic episode while in a car seat. He required minimal resuscitation but was noted to have significant hypercarbia on the blood gas. There was no history suggestive of an intercurrent respiratory infection. Systemic examination was normal apart from skeletal features of achondroplasia. While in hospital, he had further brief apnoeic episodes. Polysomnography demonstrated central and obstructive sleep apnoeas (Apnoea Hypopnoea Index (AHI) is used to quantify the number of apnoeas and
hypopnoeas scored per hour1 and was found to be significantly elevated at 26.3/h). Subsequent to this, spinal T2-weighted MRI scans (figure 1) were undertaken. In light of the abnormal MRI, the neurosurgical team was consulted and a procedure was planned. To allow time to grow and improve the chances of a successful operation, he received non-invasive ventilation (Bilevel Positive Airway Pressure (BiPAP)) at night. However, he had a further significant apnoeic episode. He underwent an urgent neurosurgical procedure. Figure 2 demonstrates the postoperative spinal T2-weighted MRI scans. QUESTIONS 1. What are the causes of recurrent apnoeas in children with achondroplasia? 2. What is the abnormality shown in figure 1? 3. What is the neurosurgical procedure undertaken?
Figure 1 Pre-operative sagittal T2-weighted image of posterior fossa and upper spine.
Figure 2 Post-operative sagittal T2-weighted image of posterior fossa and upper spine.
Babiker MOE, et al. Arch Dis Child Educ Pract Ed 2014;0:1. doi:10.1136/archdischild-2014-306883
1
Copyright Article author (or their employer) 2014. Produced by BMJ Publishing Group Ltd under licence.
Downloaded from http://ep.bmj.com/ on April 16, 2015 - Published by group.bmj.com
EPILOGUE 3
ANSWERS 1. Apnoea is usually multifactorial. In addition to central causes, such as cervicomedullary compression, mechanical causes include small thorax, narrow upper airways due to underdevelopment of the mid face and adenotonsillar hypertrophy. Risk of sudden death in achondroplastic children below 5 years was estimated in one study to be 50-fold higher than in the normal population.2 This has been linked to brainstem compression in over half of the cases.3 The American Academy of Paediatrics recommends baseline neuroimaging of all children with achondroplasia during infancy.4 Because of the narrow space around the brainstem and cervical cord along with a relatively large head, it has been recommended that the use of baby swings and carrying slings as well as rearward facing car seats should be avoided in these children.5 2. Figure 1 shows significant cord compression at the cervicomedullary junction. The anteroposterior diameter of the spinal canal at the craniocervical junction was 2.8 mm, more than two SDs below the mean measurement for achondroplasia.6 Children with achondroplasia are at increased risk of foramen magnum stenosis secondary to underdevelopment of the occiput.6 This case illustrates that cervicomedullary junction obstruction should be considered in any child with achondroplasia presenting with recurrent acute life-threatening events. 3. This patient underwent foramen magnum decompression to create extra space at the craniocervical junction as demonstrated in figure 2. Postoperative polysomnography demonstrated significant improvement in his ventilation (AHI 5.7/h). He no longer required BiPAP and continued to thrive well. Mohamed O E Babiker,1 Christopher Edwards,2 Philip Davies,2 Roddy O’Kane1,3 1
Fraser of Allander Neurosciences Unit, Royal Hospital for Sick Children, Glasgow, UK 2 Respiratory Department, Royal Hospital for Sick Children, Glasgow, UK
Neurosurgery Department, Institute of Neurosciences, Southern General Hospital, Glasgow, UK Correspondence to Dr Mohamed O E Babiker, Fraser of Allander Neurosciences Unit, Royal Hospital for Sick Children, Dalnair Street, Yorkhill, Glasgow G3 8SJ, UK; [email protected]
Contributors MOEB and CE wrote the provisional manuscript. PD revised the polysomnography data and edited the final draft and ROK reviewed the MRI images. All authors have contributed to the clinical management of this case. Competing interests None. Patient consent Obtained. Ethics approval Provenance and peer review Not commissioned; externally peer reviewed. To cite Babiker MOE, Edwards C, Davies P, et al. Arch Dis Child Educ Pract Ed Published Online First: [ please include Day Month Year] doi:10.1136/ archdischild-2014-306883 Received 31 May 2014 Accepted 8 October 2014
REFERENCES 1 Berry RB, Budhiraja R, Gottlieb DJ, et al. Rules for scoring respiratory events in sleep: update of the 2007 AASM Manual for the Scoring of Sleep and Associated Events. J Clin Sleep Med 2012;8:597–619. 2 Wynn J, King TM, Gambello MJ, et al. Mortality in achondroplasia study: a 42-year follow-up. Am J Med Genet A 2007;143A:2502–11. 3 Hecht JT, Francomano CA, Horton WA, et al. Mortality in achondroplasia. Am J Hum Genet 1987;41:454–64. 4 Trotter TL, Hall JG. Health supervision for children with achondroplasia. Pediatrics 2005;116:771–83. 5 Wright MJ, Irving MD. Clinical management of achondroplasia. Arch Dis Child 2012;97:129–34. 6 Hecht JT, Horton WA, Reid CS, et al. Growth of the foramen magnum in achondroplasia. Am J Med Genet 1989; 32:528–35.
Arch Dis Child Educ Pract Ed 2014;0:1. doi:10.1136/archdischild-2014-306883
1
Downloaded from http://ep.bmj.com/ on April 16, 2015 - Published by group.bmj.com
Recurrent acute life-threatening events in a child with achondroplasia Mohamed O E Babiker, Christopher Edwards, Philip Davies and Roddy O'Kane Arch Dis Child Educ Pract Ed published online November 3, 2014
Updated information and services can be found at: http://ep.bmj.com/content/early/2014/11/03/archdischild-2014-306883
These include:
Email alerting service
Topic Collections
Receive free email alerts when new articles cite this article. Sign up in the box at the top right corner of the online article.
Articles on similar topics can be found in the following collections Rheumatology (63) Clinical diagnostic tests (90) Radiology (78) Radiology (diagnostics) (72) Resuscitation (13)
Notes
To request permissions go to: http://group.bmj.com/group/rights-licensing/permissions To order reprints go to: http://journals.bmj.com/cgi/reprintform To subscribe to BMJ go to: http://group.bmj.com/subscribe/
