Obstructive sleep apnoea with Arnold-Chiari malformation.

Abstract

A case of obstructive sleep apnoea associated with the Arnold-Chiari malformation is described, in which the loss of pharyngeal sensation seems to have played an important part in the aetiology of the obstruction of the upper airway. (Thorax 1995;50:690-691) Keywords: obstructive sleep apnoea, Arnold-Chiari malformation, airways obstruction.Obstructive sleep apnoea usually arises when anatomical factors narrow the upper airway or lead to an increase in negative intraluminal pressure. However, most reports of sleep disorders in patients with neuromuscular disease have found central sleep apnoea'2; obstructive episodes have been reported in some34 but not all5 cases where sleep apnoea coexists with an Arnold-Chiari malformation.Arnold-Chiari malformation is a disorder in which the cerebellar tonsils herniate through the foramen magnum producing variable signs and symptoms of cerebellar, cervical, and/or brainstem dysfunction. Surgical correction of this problem has been reported to produce a dramatic improvement in the symptoms of the associated sleep apnoea, but follow up has been relatively brief.3 We report a case of obstructive sleep apnoea associated with Arnold-Chiari malformation where mechanisms other than upper airway narrowing appeared to operate, and where a longer follow up has led us to revise our initially optimistic view of surgical treatment.Case report A 62 year old man presented with two "black outs", one following a coughing bout. He admitted to hypersomnolence and was a loud snorer. His wife had witnessed apnoeas during sleep, together with attacks of coughing and choking. He was mildly overweight with a collar size of 16 inches (40 cm) and body mass index of 27-4, but no neurological abnormality was detected at presentation. A provisional diagnosis of cough syncope together with obstructive sleep apnoea was made and polysomnography was performed. This showed repeated obstructive apnoeic episodes (table) irrespective of body position associated with considerable difficulty in swallowing saliva during his sleep. Nasal continuous positive airway pressure was tried but was not tolerated.At follow up three months after presentation he reported progressive difficulty in walking. On examination he had a positive Romberg's sign and dysarthria. Over the next few weeks he developed diplopia and, subsequently, difficulty in swallowing. At this point his gag reflex was noted to be absent, whilst horizontal and vertical nystagmus together with features of cerebellar ataxia were present.Myelography and magnetic resonance imaging (MRI) of his head and cervical spine revealed an Arnold-Chiari malformation with the cerebellar tonsils prolapsed to C2. There was kinking of the medulla by the inferior tip of the clivus, but no hydrocephalus or syrinx were demonstrated.He underwent a preliminary tracheostomy followed by a decompressive laminectomy to C2 and debulking of both cerebellar tonsils. Postoperatively his swallowing was good and pulse oximetery with an open tracheostomy revealed no oxygen desat...

Chiari Malformation and Sleep-Disordered Breathing: A Review of Diagnostic and Management Issues

“…On the basis of this patient suffering a respiratory arrest they recommended continued surveillance. 18 Similarly, Ely et al described a patient who developed sleep apnea five years after surgical correction of her CM. Unfortunately, there was no polysomnogram prior to the surgery, limiting definitive exclusion of the possibility of preoperative sleep apnea, although she had had no suggestive symptoms.…”

Obstructive and central sleep apnoea in Arnold–Chiari malformation: resolution following surgical decompression

“…Obstructive sleep apnoea has also been noted in association with ACM [2,3]. Postulated mechanisms include reduction or loss of hypoxic ventilatory drive resulting in prolonged apnoeas [3], reduced muscle tone of pharyngeal dilators [3], and loss of upper airway sensation [2,10].…”

“…Postulated mechanisms include reduction or loss of hypoxic ventilatory drive resulting in prolonged apnoeas [3], reduced muscle tone of pharyngeal dilators [3], and loss of upper airway sensation [2,10]. Loss of upper airway sensation may interfere with the protective pharyngeal dilator mechanisms activated by subatmospheric pressures in the pharynx and possibly by the vibration of snoring [10].…”

“…Both obstructive and central sleep apnoea have been reported in association with ACM [1][2][3]. There are several hypotheses regarding the possible causes of central sleep apnoea.…”

“…Both obstructive and central sleep apnoea have been reported in association with ACM [1][2][3]. We report the case of a young patient with type I Arnold-Chiari malformation who presented with a lung abscess and symptoms of obstructive sleep apnoea.…”