Acute respiratory compromise due to bilateral pneumothoraces in a patient with Rett syndrome

Summary

This is a case of acute respiratory distress in a nine‐year‐old with severe Rett syndrome who required immediate anaesthetic assistance in the emergency department and during her subsequent hospital stay. Rett syndrome is a rare inherited neurodevelopmental disease that more commonly affects females. It is characterised by a period of normal development up to between six and 18 months of age, followed by a gradual but progressive loss of developmental skills leading to severe cognitive and physical decline. Other features include autistic‐type behaviour, oral‐motor and autonomic dysfunction and gastrointestinal disturbance. Patients can present for elective surgery for scoliosis correction, ear, nose and throat procedures or placement of a gastrostomy. They can also present acutely, either with an un‐associated condition or due to aspiration from a poor gag or swallow. This report highlights the specific risks relevant to anaesthesia in patients with Rett syndrome, especially in considering the association with bilateral apical bullae and pneumothorax which could impact on the ventilation strategy.

Introduction

Patients with neurodevelopmental conditions often have multisystem disease with numerous risk factors for peri‐operative morbidity and mortality. Rett syndrome is an increasingly diagnosed condition that primarily affects girls and follows a period of normal development [1]. It results from mutations in the genes encoding methyl‐cytosine‐guanosine binding protein 2 (MECP2) located on the X chromosome [2]. The diagnosis is based on progressive neurological deterioration characterised by a loss of developmental milestones at between six and 18 months of age in a previously thriving child [3]. Other significant associations include scoliosis (up to 50% of patients), autistic‐like behaviour, vasomotor abnormalities as well as prolonged QT interval [4]. There are numerous associated respiratory abnormalities including periodic breathing with hyperventilation, breath holding and apnoeas, as well as respiratory insufficiency due to advancing scoliosis. Patients with Rett syndrome present for neuroimaging and diagnostic procedures, as well as for interventions such as gastrostomy for nutritional requirements. There is an increased incidence of pulmonary inflammatory infiltrates, particularly in the upper lobes, which can adversely affect ventilation in the anaesthetised patient. There is no cure for Rett syndrome, and treatment is therefore aimed at delaying symptom progression. Most people with Rett syndrome live into middle age and beyond, and as such will continue to present for procedures necessitating general anaesthesia. This case demonstrates the particular nuances that anaesthetists should be aware of when treating patients with Rett syndrome.

Report

A nine‐year‐old girl with Rett syndrome presented to the emergency department in acute respiratory distress. A history of sudden onset choking while eating soup at home was given, which was followed by a period of cyanosis and collapse. Her past medical history included severe learning difficulties and epilepsy. She was prescribed multiple anti‐epileptic medications. A gastrostomy had been inserted 18 months previously under general anaesthesia with no apparent complications. On arrival to hospital, her Glasgow Coma Scale score was recorded as 5 (E1, V1, M3). She was self‐ventilating at a rate of 50 breaths.min^‐1 with facemask oxygen and her peripheral oxygen saturations were 40–50%. No air entry was heard on either side of the chest on auscultation. She had excessive use of her accessory muscles of respiration. Her non‐invasive blood pressure was elevated at 159/79 mmHg and her skin was cool peripherally. Her blood glucose level was normal and there was no evidence of any injuries. Ventilation was attempted via a facemask and a Mapleson C breathing circuit. This did not improve oxygenation.

Anaesthesia was induced with fentanyl 30 μg, ketamine 60 mg and rocuronium 40 mg i.v., after which her trachea was intubated successfully with a 6‐mm internal diameter cuffed oral tracheal tube using a size 3 McGrath videolaryngoscope (Aircraft Medical Ltd, Edinburgh, UK). No foreign body was seen in her upper airway. Her oxygen saturation improved to 70% but then plateaued. A post‐intubation chest radiograph demonstrated the presence of massive bilateral pneumothoraces, prompting bilateral needle decompression in the second intercostal space at the mid‐clavicular line with two 18 gauge cannulae. Following this she had bilateral 12 gauge intercostal drains inserted which both aspirated air and demonstrated bubbling when attached to the underwater circuits. Her oxygen saturations improved to around 95% following these interventions.

Following initial resuscitation, the patient underwent urgent fibreoptic bronchoscopy in the operating theatre which demonstrated a normal and patent airway down to the level of the main bronchi. Gastroscopy revealed a high bolus obstruction in her oesophagus, presumed to have been food debris from her presentation, but no other abnormality was found. She was transferred to the paediatric intensive care unit (PICU) postoperatively for ongoing care. Her lungs were ventilated using a pressure control mode with peak inspiratory pressure of 20 cmH₂O, at a rate of 16 breaths.min^‐1. She was sedated with morphine and midazolam.

Over the following days, she had recurrent re‐accumulation of her pneumothoraces despite having two chest drains in situ, both on suction. Computed tomography of her chest demonstrated bilateral apical bullae and a referral was made to the general surgeons for consideration of an apical bullectomy. She underwent a unilateral thoracoscopic bullectomy and pleurodesis, facilitated by one‐lung ventilation, during which the surgeons commented on the vascular adhesions present in the lung apex, a finding that supports the presence of chronic inflammatory changes known to be associated with lung disease in patients with Rett syndrome. She returned to PICU for a further week before returning to theatre for the repeat procedure on the contralateral side. Postoperatively, she tolerated removal of both chest drains and was discharged to the ward. She remained an inpatient for another week while was recovered from her surgery before being discharged home with plans for outpatient follow‐up.

Discussion

Rett syndrome is a relatively rare disease, affecting about 1:10,000 female live births, although it represents the second most common cause of severe intellectual disability (behind Trisomy 21) [5]. Patients with Rett syndrome frequently require anaesthesia, including for imaging for neuro‐diagnostic purposes and surgical interventions aimed at symptom modification such as spinal fusion for scoliosis or gastrostomy insertion for feeding. Due to the multisystem nature of their condition, they can also present in an emergency, requiring immediate intervention. Indications can include airway obstruction from an inhaled or regurgitated foreign body, haemodynamic collapse from an arrhythmia secondary to a prolonged QT interval or from a disease process independent of Rett syndrome such as acute appendicitis.

Respiratory disorders are common and include hyperventilation and spontaneous Valsalva manoeuvres [6]. Historically, this was attributed to a dysfunctional central control centre but is now considered to be multi‐factorial, with studies indicating that a chronic inflammatory process underpins the clinical manifestation [7]. These changes appear to be more prevalent in the lung apices, increasing the risk of bullous changes. This disease process can take many years to manifest and patients can be well into their teens before any respiratory symptoms become apparent. In our case, the initial diagnosis was presumed to be aspiration of a foreign body leading to severe and acute respiratory deterioration. A negative bronchoscopy resulted in consideration of an alternative diagnosis – the presence of previously asymptomatic apical bullae with thin alveolar membranes that ruptured on coughing during feeding. This would explain both the difficulty with ventilation despite successful tracheal intubation, and the negative endoscopic procedures. It is important to have a high degree of suspicion for an underlying pulmonary abnormality and if the clinical situation permits, to perform imaging before instituting mechanical ventilation. In an elective setting, we would recommend that a chest radiograph be performed before surgery. Though chest imaging before tracheal intubation is not always possible in emergency cases, including the one reported above, it is prudent to ensure that the equipment to treat pneumothorax is immediately available.

Apart from the respiratory complications mentioned, the anaesthetist should be cognisant of other features associated with Rett syndrome which may complicate management. Performing a thorough pre‐operative assessment is mandatory with particular attention to the presence of regurgitation, any abnormalities on the electrocardiograph (frequently prolonged QTc) [8], known cardiorespiratory insufficiency and previous anaesthetic experience. Early postoperative care is usually best provided in a critical care area.

Patients with Rett syndrome present specific challenges to the anaesthetist and knowledge of these can facilitate safe peri‐operative care. Patients who present with sudden respiratory distress are particularly complex, especially adolescents with more advanced disease states. This case demonstrates the association of Rett syndrome with bilateral apical bullae which can mimic an acute airway emergency but with significant differences in treatment. The priority should remain oxygenation of the patient but if this proves insufficient despite a secured airway, consideration should be given to the presence of an alternative diagnosis. Prompt chest radiography or ultrasound may aid in this process and should be sought in a timely manner.