Tracheomalacia in a patient with Turner's syndrome treated successfully with an intra-tracheal stent
Article Outline
Summary
A patient with Turners syndrome and type II respiratory failure is described. Treatment with non-invasive ventilation alone was unsuccessful, but was sufficient to manage the patient once tracheomalacia had been identified and treated with a tracheal stent.
Keywords: Turner's syndrome, Obesity, Non-invasive ventilation, Tracheal stenting
Introduction
Tracheomalacia is a rare and potentially fatal condition. In the current literature, it is increasingly recognised in both adults and children. It has not previously been described in a patient with Turner's syndrome and is not commonly thought of as a cause of failure to ventilate with non-invasive ventilation (NIV). We present a case of a 52-year-old women with Turner's syndrome who was found to have tracheomalacia when she became increasingly difficult to ventilate; successfully treated with an intra-tracheal stent.
Description of case
The 52-year-old woman was transferred to our unit following an acute admission to another hospital with type II respiratory failure, which became compounded by a hospital acquired pneumonia. Prior to admission she described increasing hypersomnolence, loud snoring and morning headache consistent with sleep disordered breathing.
She had the typical phenotype of Turner's syndrome, short stature, a short, webbed neck and obesity. Her nasopharynx was crowded and she was noted to have a high-pitched voice, but other than occasional crepitations at her lung bases and marked peripheral oedema, her examination was normal. Arterial blood gasses on admission showed a H+ 44.9, PaCO2 12.9
kPa, PaO2 11.0kPa breathing 1l O2 via nasal cannulae.
A chest X-ray showed an elevated right hemi-diaphragm and alveolar shadowing at the bases. A provisional diagnosis of obstructive sleep apnoea (OSA)/obesity hypoventilation overlap syndrome was made. Echocardiography showed good left ventricular function, but mild impairment and dilatation of the right ventricle. She was offered NIV aggressively, trying a range of machines and interventions but continued to deteriorate. Overnight respiratory monitoring revealed severe desaturation to less than 60% and a gradual rise in transctaneous CO2 over night to 18kPa. Blood gases that morning revealed acute on chronic acidotic respiratory failure with H+ 62.6, PaCO2 18.0kPa, PaO2 8.5kPa, HCO3 52. She was drowsy and increasingly difficult to ventilate, with little air movement in the chest despite applied airway pressures greater than 30cm H2O. For this reason and because of concern about an upper airway lesion, it was considered that intubation and investigation of her upper airways was warranted.
She was intubated and ventilated and subsequently a tracheostomy, guided by ridgid bronchoscopy, was performed by the thoracic surgeons. At the time during passive expiration prolapse of the posterior tracheal wall was sufficient to almost completely occlude the airway. Fiberoptic bronchoscopy via tracheostomy tube revealed that the tracheomalacia also involved the main bronchi (Figure 1). Pressures of more than 35 were required to keep the airway patent, despite thorough treatment of her pneumonia. Following discussion with the patient, a 20×60mm uncovered metal stent was inserted in to the trachea.
Figure 1.
The trachea at rigid bronchoscopy in jet ventilation (left) and passive expiration (right).
Following this she did well, quickly mobilising and eating and drinking normally, and only requiring overnight NIV (Breas 403). Repeat overnight respiratory monitoring showed stable transcutaneous CO2 and only minor oxygen desaturation.
Discussion
Turner's syndrome is the genetic syndrome occurring from the karyotype 45 X0. It occurs in about 1 in 2000 live female births but a larger proportion of spontaneously aborting foetuses. It is associated with thyroid problems, cardiac and renal anomalies, infertility and hearing impairment. The phenotype is of characteristic short stature, short 4th metacarpals, widened carrying angle, a shield chest and a webbed shortened neck. Turner's patients are often obese1; along with the above associations obesity is thought to contribute to the shortened life expectancy of these patients.
Obesity hypoventilation is a recognised cause of chronic type II respiratory failure and along with OSA results in pulmonary hypertension and irreversible lung damage. Tracheomalacia is most commonly associated with tracheal intubation and tracheostomy; however, outside these conditions it can be primary or secondary. Primary causes mainly related to congenital malformation or cartilaginous disorders. Secondary causes include recurrent inflammation of the airways or external pressure.2
This case raises two important questions. The first is whether tracheomalacia may be more common in obesity than previously considered; such patients seldom come to bronchoscopy and the usual treatment for obesity hypoventilation, non-invasive positive pressure ventilation, is also a recognised treatment for tracheomalacia.3 Tracheomalacia would also be consistent with the flow volume loops showing extra-thoracic compression seen in some obese patients.
Secondly, the possibility arises that tracheomalacia could be a part of the Turner's phenotype. Patients with Turner's syndrome are as discussed at increased risk of obesity and therefore have increased risk of OSA and obesity hypoventilation. But recent research is increasingly implicating the X-chromosome in linear growth and development of both bone and cartilage. It has been demonstrated that the short stature and phenotype of the Turner's patient is caused by the lack of the SHOX (short stature homebox) gene. This gene is not only implicated in idiopathic short stature, but also Leri–Weill Dyschondrosteosis and other genetic syndromes including bony abnormalities of the wrist, abnormal short stature, hearing problems and craniofacial abnormalities.4, 5 These connections lead to the hypothesis that the underlying genetic abnormality in our and other Turner's syndrome patients renders their tracheal cartilage more at risk from tracheomalacia.
This case serves to increase our awareness of tracheomalacia and suggest increased investigation to diagnose and treat the condition in obese patients with hypoventilation syndromes. Tracheal stenting is an option where other treatment modalities have been ineffective.
Conflict of interest statement
There is no conflict of interest for any of the authors of this case report.
References
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PII: S1755-0017(07)00002-4
doi:10.1016/j.rmedc.2007.11.001
© 2007 Elsevier Ltd. All rights reserved.
