Guidelines for diagnosis and management of congenital central hypoventilation syndrome

BACKGROUND

Congenital Central Hypoventilation Syndrome (CCHS) is a rare condition characterized by an alveolar hypoventilation due to a deficient autonomic central control of ventilation and a global autonomic dysfunction. Paired-like homeobox 2B (PHOX2B) mutations are found in most of the patients with CCHS. In recent years, the condition has evolved from a life-threatening neonatal onset disorder to include broader and milder clinical presentations, affecting children, adults and families. Genes other than PHOX2B have been found responsible for CCHS in rare cases and there are as yet other unknown genes that may account for the disease. At present, management relies on lifelong ventilatory support and close follow up of dysautonomic progression. BODY: This paper provides a state-of-the-art comprehensive description of CCHS and of the components of diagnostic evaluation and multi-disciplinary management, as well as considerations for future research.

CONCLUSION

Awareness and knowledge of the diagnosis and management of this rare disease should be brought to a large health community including adult physicians and health carers.

Reversible Central Hypoventilation Syndrome in Basilar Invagination

BACKGROUND

A noninvasive approach for basilar invagination (BI) and moreover, cervical traction to reduce odontoid invagination, has not been thoroughly described in the literature. We report a case of BI with Arnold-Chiari malformation in which preoperative reduction using Gardner well cervical traction was attempted and the patient developed central hypoventilation syndrome.

CASE DESCRIPTION

A 15-year-old boy presented with a 6-month history of progressive cervical myelopathy signs and symptoms, modified Japanese orthopedic association score 12 of 18. Radiology showed type A BI with occipitalization of atlas and a posterior arch defect of axis. A preoperative closed cervical traction followed by occipitocervical fusion via a posterior-only approach was planned. The patient developed 3 episodes of apnea on sleeping when on traction. Labeled as central hypoventilation, he was operated by foramen magnum decompression and occipitocervical fusion.

CONCLUSIONS

Cervical traction followed by posterior fixation is an effective way to manage basilar invagination with Arnold-Chiari malformation and assimilated C1. However, patients should be monitored closely for respiratory dysfunction.

Evaluating the evidence: is phrenic nerve stimulation a safe and effective tool for decreasing ventilator dependence in patients with high cervical spinal cord injuries and central hypoventilation?

INTRODUCTION

Case reports, case series and case control studies have looked at the use of phrenic nerve stimulators in the setting of high spinal cord injuries and central hypoventilation syndromes dating back to the 1980s. We evaluated the evidence related to this topic by performing a systematic review of the published literature.

METHODS

Search terms "phrenic nerve stimulation," "phrenic nerve and spinal cord injury," and "phrenic nerve and central hypoventilation" were entered into standard search engines in a systematic fashion. Articles were reviewed by two study authors and graded independently for class of evidence according to published guidelines. The published evidence was reviewed, and the overall body of evidence was evaluated using the grading of recommendations, assesment, development and evaluations (GRADE) criteria Balshem et al. (J Clin Epidemiol 64:401-406, 2011).

RESULTS

Our initial search yielded 420 articles. There were no class I, II, or III studies. There were 18 relevant class IV articles. There were no discrepancies among article ratings (i.e., kappa = 1). A meta-analysis could not be performed due to the low quality of the available evidence. The overall quality of the body of evidence was evaluated using GRADE criteria and fell within the "very poor" category.

CONCLUSION

The quality of the published literature for phrenic nerve stimulation is poor. Our review of the literature suggests that phrenic nerve stimulation is a safe and effective option for decreasing ventilator dependence in high spinal cord injuries and central hypoventilation; however, we are left with critical questions that provide crucial directions for future studies.

Phrenic nerve stimulation for diaphragm pacing in a quadriplegic patient

Chronic hypoventilation due to injury to the brain stem respiratory center or high cervical cord (above the C3 level) can result in dependence to prolonged mechanical ventilation with tracheostomy, frequent nosocomial pneumonia, and prolonged hospitalization. Diaphragm pacing through electrical stimulation of the phrenic nerve is an established treatment for central hypoventilation syndrome. We performed chronic phrenic nerve stimulation for diaphragm pacing with the spinal cord stimulator for pain control in a quadriplegic patient with central apnea due to complete spinal cord injury at the level of C2 from cervical epidural hematoma. After diaphragmatic pacing, the patient who was completely dependent on the mechanical ventilator could ambulate up to three hours every day without aid of mechanical ventilation during the 12 months of follow-up. Diaphragm pacing through unilateral phrenic nerve stimulation with spinal cord stimulator was feasible in an apneic patient with complete quadriplegia who was completely dependent on mechanical ventilation. Diaphragm pacing with the spinal cord stimulator is feasible and effective for the treatment of the central hypoventilation syndrome.