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Unusual breathing in a 7 year old

BMJ 2012; 344 doi: http://dx.doi.org/10.1136/bmj.e3022 (Published 09 May 2012) Cite this as: BMJ 2012;344:e3022
  1. F Abel, clinical fellow in respiratory medicine1,
  2. D Kilner, consultant, respiratory paediatrics1,
  3. S Sonnappa, consultant, respiratory paediatrics12
  1. 1Great Ormond Street Hospital for Children, London WC1N 3JH, UK
  2. 2UCL Institute of Child Health, London, UK
  1. Correspondence to: F Abel frantoop{at}gmail.com

A 7 year old girl was referred for a sleep study after her parents noticed unusual breathing while she slept. Her breathing was described as slow with many pauses.

After a normal term delivery, she was diagnosed with truncus arteriosus associated with a large ventricular septal defect. Both were surgically repaired at age 1 month, with uneventful postoperative recovery and normal subsequent cardiac function.

She had no overt dysmorphic features. She was nasogastrically fed from age 7 months for failure to thrive after feeding difficulties, then via a gastrostomy from age 2.5 years until 4 years. A clinical diagnosis of DiGeorge syndrome was confirmed by detection of a 22q11.2 deletion on genetic analysis.

By age 6 years, she was fully orally fed and swallow assessment was normal.

She remained clinically well until age 7 years, when the unusual breathing started. A history of choking on food and drinks, difficulty coping with oral secretions, and frequent drooling was elicited from her parents.

Clinical examination was normal. A videofluoroscopic swallow assessment showed obvious aspiration.

A cardiorespiratory sleep study was performed and the following summary was obtained (fig 1).

Figure1

Fig 1 Cardiorespiratory sleep study

Questions

  • 1 What does fig 1 represent and how would you interpret it?

  • 2 What is the probable cause of the abnormality?

  • 3 What further investigations should be performed?

  • 4 What management would you suggest?

Answers

1 What does fig 1 represent and how would you interpret it?

Short answer

The figure is a two minute epoch from a cardiorespiratory sleep study. It shows severe bradypnoea, with recurrent episodes of central apnoea in a pattern of periodic breathing. Each central apnoea causes severe oxygen desaturation.

Long answer

This is a cardiorespiratory polysomnography split screen with a two minute epoch in the upper panel showing electrocardiography (ECG), end tidal carbon dioxide, thoracic and abdominal movements, and oxygen saturation (Spo2). The bottom panel shows overall oxygen saturation and carbon dioxide trend for the night.

The respiratory overview in the bottom panel shows ongoing severe desaturations for the duration of the study, with relatively well maintained carbon dioxide. The detailed epoch shows periodic breathing—at least three consecutive episodes of central apnoea of at least three seconds each, separated by an interval of normal breathing of no longer than 20 seconds.1 Each central apnoea causes desaturation to low 80% values. The respiratory rate is 5 breaths/min.

2 What is the probable cause of the abnormality?

Short answer

Severe central apnoea syndrome in children suggests a problem at the level of the brainstem. Because of the associated swallow impairment, the most likely diagnosis is an Arnold-Chiari malformation type 1 (herniation of the cerebellar tonsils through the foramen magnum).

Long answer

The patient has a severe central apnoea syndrome—periodic breathing as previously defined,1 with recurrent central apnoeas, bradypnoea, and severe associated desaturations. These findings suggest a problem with the central command of breathing. The problem probably originates from the respiratory centres, which are located in the brainstem at the level of the medulla.

The most likely diagnosis is an Arnold-Chiari malformation type 1. This is a congenital brainstem abnormality characterised by a caudal herniation of the cerebellar tonsils and crowding of the craniocervical junction.2 Sleep disordered breathing may be the only symptom.3 Other common symptoms are swallow impairment, neck pain, and headache. Other conditions associated with central apnoeas include congenital hypoplasia of the brainstem and cerebellum, congenital central hypoventilation syndrome, Prader-Willi syndrome, achondroplasia, and brainstem tumours.

3 What further investigations should be performed?

Short answer

Magnetic resonance imaging of the brain, including views of the brainstem.

Long answer

Neuroimaging, including magnetic resonance imaging of the brain with sagittal views of the brainstem, is the gold standard test to diagnose a suspected brainstem abnormality.4

The radiographic criterion for Arnold-Chiari malformation type 1 is a downward herniation of the cerebellar tonsils more than 5 mm below the foramen magnum (fig 2). This was the cause of the central apnoeas in our patient. Formation of a syrynx—an abnormal, cerebrospinal fluid filled, internal dilation of the central canal of the spinal cord, with possible compression of the spinal cord—may be an associated finding. However, this was not present in our patient. Other investigations include videofluoroscopic swallow assessment if there are signs of associated impaired swallowing.

Figure2

Fig 2 Sagittal T1 weighted magnetic resonance image showing Arnold-Chiari type 1 malformation (arrow; downward herniation of the cerebellar tonsils >5 mm below the foramen magnum)

4 What management would you suggest?

Short answer

Neurosurgical decompression of the foramen magnum is recommended to relieve the compression of the brainstem and improve circulation of the cerebrospinal fluid.

Long answer

Surgical posterior decompression of the foramen magnum needs to be performed relatively soon after diagnosis to prevent progression of the neurological symptoms and possible formation or aggravation of a syrynx.

The operation involves a craniectomy with removal of bone at the back of the cranium. This is covered by a dural graft. A cervical laminectomy is also performed to create even more space in the area and reduce the risk of compression to a minimum.

Reports show that symptoms typical of Arnold-Chiari malformation type 1, such as central apnoea syndrome, neck pain, and impaired swallowing, improve after posterior decompression surgery.5

Patient outcome

Although our patient’s swallowing improved after surgery 10 months ago, she still needs non-invasive ventilatory support during sleep. We hypothesise this is related to persistent kinking of the brainstem, with more of an effect on her breathing pattern than swallow function. We monitor this every six months with formal sleep study assessments. To our knowledge, an association has not been found between DiGeorge syndrome and Arnold-Chiari malformation, which is more commonly diagnosed in otherwise healthy children.3

Notes

Cite this as: BMJ 2012;344:e3022

Footnotes

  • Competing interests: All authors have completed the ICMJE competing interests form at http://www.icmje.org/coi_disclosure.pdf (available on request from the corresponding author) and declare: no support from any organisation for the submitted work; no financial relationships with any organisations that might have an interest in the submitted work in the previous three years, no other relationships or activities that could appear to have influenced the submitted work.

  • Provenance and peer review: Not commissioned; externally peer reviewed.

  • Parental consent obtained.

References