Symposium on The Cardiopulmonary System
Obstructive sleep apnoea associated with syringomyelia Coexistence of obstructive sleep apnoea and syringomyelia is quite rare. This article discusses three cases of coexisting obstructive sleep apnoea and syringomyelia and looks at the possible mutual influences between the two diseases.
Cases
Patient 1
A 37-year-old woman who had been in a sudden coma for 1 hour was transferred to the emergency department. The patient had a 5-year history of snoring accompanied by daytime sleepiness and a 5-year history of syringomyelia, neither of which were being treated. On physical examination she was found to be in a light coma with conjunctival oedema. The vital signs were stable. Her body mass index was 28 kg/m2. Arterial blood gas analysis showed pH 7.24, partial pressure of carbon dioxide in arterial blood (PaCO2) 85.2 mmHg and Dr Chuan Shao is Pulmonary Physician in the Department of Respiratory Medicine, Ningbo Medical Treatment Center Li huili Hospital, Ningbo, 315040, China and Professor Shan-qun Li is Pulmonologist and Sleep Specialist in the Department of Pulmonary Disease, Centre of Snoring and Sleep Apnoea Medicine, Zhongshan Hospital, Fudan University, Shanghai, China Correspondence to: Dr C Shao ([email protected])
200
partial pressure of oxygen in arterial blood (PaO2) 98 mmHg (oxygen inhalation through nasal cannulae with 3 litres per minute). The patient recovered consciousness after treatment with intravenous nikethamide and lobeline and subsequently bi-level positive airway pressure was implemented (spontaneous triggering mode/timed safety mode, inspiratory positive airway pressure 16 cmH2O, expiratory positive airway pressure 6 cmH2O, Respironics, Philips, Pittsburgh, Pennsylvania, USA). Arterial blood gas analysis after 4 hours showed pH 7.30, PaCO2 55 mmHg and PaO2 98 mmHg. Polysomnography revealed an apnoea– hypopnoea index of 34.1/hour (mainly obstructive), mean oxyhaemoglobin saturation of 88.1%, and the lowest oxygen saturation of 50%. Long-term home use of bi-level positive airway pressure was started and the patient has been well since.
Patient 2
A 41-year-old woman went to a sleep clinic to seek medical consultation because of ‘snoring and daytime sleepiness’. She had snored loudly during sleep for the last 4 years and had felt daytime sleepiness for the last 2 years. The patient had 5 years’ history of syringomyelia without treatment. She was obese with a body mass index of 30.6 kg/m2. Polysomnography revealed an apnoea– hypopnoea index of 18.5/hour (mainly obstructive), mean oxyhaemoglobin saturation of 87%, and the lowest oxygen saturation of 63%. The patient began long-term home use of nasal continuous positive airway pressure and her symptoms of snoring and daytime sleepiness disappeared after 2 months.
Patient 3
A 35-year-old man went to a sleep clinic for help because of ‘snoring and choking during sleep’. The patient had snored during his sleep for the last 6 years and then felt a choking sensation which could result in awakening from sleep for the past 4 years. Accompanying symptoms included daytime sleepiness and memory loss. The patient had been diagnosed with syringomyelia 5 years earlier and he had undergone an operation for posterior fossa decompression, arachnoid adhesiolysis and spinal
© 2015 MA Healthcare Ltd
O
bstructive sleep apnoea is characterized by recurrent obstruction or collapse of the upper airway during sleep, which induces intermittent hypoxia and hypercapnia. Obstructive sleep apnoea is a major predisposing factor for systemic conditions, such as hypertension, cardiovascular disease, stroke and diabetes, so it is not unusual to find obstructive sleep apnoea accompanying various diseases in a single patient. However, obstructive sleep apnoea is a relatively rare comorbidity in patients who have syringomyelia. Syringomyelia is a rare disease with poor treatment outcomes. It is pathologically characterized by the presence of long cavities, surrounded by gliosis, in the central part of the spinal cord (Verbraecken et al, 2002). Clinical manifestations include muscle atrophy, loss of pain and temperature sensation, limb paralysis and nutrition disorders. This article reports three cases of obstructive sleep apnoea associated with syringomyelia, discusses possible pathophysiological relationships between the two diseases, and reviews the literature concerning concurrence of obstructive sleep apnoea and syringomyelia.
British Journal of Hospital Medicine, April 2015, Vol 76, No 4
h Journal of Hospital Medicine. Downloaded from magonlinelibrary.com by 139.080.123.048 on November 27, 2015. For personal use only. No other uses without permission. . All rights rese
Symposium on The Cardiopulmonary System cord cavity shunt in another hospital 5 years ago under general anaesthesia. Cervical sagittal magnetic resonance imaging of the patient before and after surgery is shown in Figure 1. Physical examination showed left facial hypoalgesia, grade IV muscle strength of the right forearm, and surgical scars on his neck and right forearm. The patient’s body mass index was 22.9 kg/m2. Polysomnography revealed an apnoea–hypopnoea index of 113.5/hour (mainly obstructive), mean oxyhaemoglobin saturation of 91.4%, and the lowest oxygen saturation of 78%. The original waveform of his overnight polysomnography is shown in Figure 2 and the summary chart in Figure 3. The patient was treated with continuous positive airway pressure: the symptoms of snoring and choking disappeared and his overnight oxygen saturation returned to normal after treatment. The patient began long-term home use of nasal continuous positive airway pressure and has subsequently remained well.
© 2015 MA Healthcare Ltd
Discussion
Syringomyelia is detected in 32–74% of patients with a Chiari I malformation (Masson and Colombani, 2005) and Chiari I malformation frequently causes obstructive or central sleep-disordered breathing and potentially serious disturbances such as respiratory failure, syncope and even sudden death (St Louis et al, 2014). So obstructive sleep apnoea in some syringomyelia patients could be caused by the combined effect of craniovertebral junction malformation. This article has reported three cases of obstructive sleep apnoea with syringomyelia but without Chiari I malformation and focusses on the relationship between obstructive sleep apnoea and simple syringomyelia. Syringomyelia, obstructive sleep apnoea and coexistence of the two diseases can all lead to respiratory failure. Syringomyelia is a rare cause of respiratory failure. The specific mechanism may be related to flaccid paralysis of the respiratory muscles of the chest wall (Karnik et al, 1994) because the spinal cord, as an important respiratory centre, contains motor neurons in the anterior horn that stimulate the respiratory muscles. For example, at the C3–C5 level the spinal cord stimulates the diaphragm and at the thoracic level it stimulates the intercostal and abdominal muscles. Obstructive sleep apnoea can also lead to respiratory failure, especially in obese patients with severe hypoxaemia at night (Karnik et al, 1994). Respiratory failure induced by obstructive sleep apnoea has also been called ‘near miss’ death syndrome. Patients with obstructive sleep apnoea who have hypoxaemia and hypercapnia are more likely to develop severe respiratory failure and even death than those simply with hypoxaemia. Recurrent respiratory failure of near miss death syndrome can be reversed by effective treatment of obstructive sleep apnoea (Fletcher et al, 1991). British Journal of Hospital Medicine, April 2015, Vol 76, No 4
Figure 1. Cervical sagittal magnetic resonance imaging of patient 3 before and after his operation. a. Magnetic resonance imaging showed low T1 signal in the lower medulla oblongata and cervical spinal cord, cervical magnetic resonance imaging showed spinal cord central canal expansion below the level of C2. b. Magnetic resonance imaging showed postoperative changes.
Figure 2. Original waveform of night polysomnography of patient 3. The green wave shows nasal airflow and the yellow wave shows abdominal movement when breathing. The parts of the green wave in the pink areas indicate the suspension of nasal airflow when abdominal movement remained, suggesting obstructive sleep apnoea.
Pływaczewski et al (2009) reported a case of respiratory failure caused by severe obstructive sleep apnoea. The patient was a 52-year-old man with body mass index of 46.2 kg/m2, first diagnosed as having ‘respiratory failure and polycythaemia’. Polysomnography showed the respiratory disturbance index was 60/hour. Arterial blood gas indices gradually returned to normal during effective auto-continuous positive airway pressure treatment. After 1 month of auto-continuous positive airway pressure treatment at home, the blood morphology and PaCO2 201
h Journal of Hospital Medicine. Downloaded from magonlinelibrary.com by 139.080.123.048 on November 27, 2015. For personal use only. No other uses without permission. . All rights rese
Figure 3. Summary chart of polysomnography results of patient 3. Horizontal axis represents time and vertical axis represents polysomnography parameters. Equipment was the nine lead Embletta PDS from ResMed, Australia.
returned to normal and the patient’s oxygenation status improved too. Verbraecken et al (2002) reported a case of a patient with syringomyelia and sleep apnoea who also had chronic respiratory failure. The patient’s condition improved quickly and significantly with use of noninvasive ventilation. The patient’s exercise tolerance and degree of arousal increased while hypercapnia and hypoxaemia disappeared. Mechanical ventilation at night helped to restore the patient’s respiratory drive during the daytime, to correct hypoxia, and improve heart function at the same time. However, in the first of the current patients, a high PaCO2 and a good response to treatment with respiratory stimulants indicated decreased respiratory muscle strength. The authors can not rule out a likely diagnosis of chronic obstructive pulmonary disease without the results of pulmonary function tests, so the diagnosis of overlap syndrome may be more accurate for this patient. In this case, type 2 respiratory failure may be caused largely by obstructive ventilation dysfunction and respiratory muscle fatigue. Continuous positive airway pressure remains the accepted standard treatment for obstructive sleep apnoea and overlap syndrome. The first 202
patient was treated successfully with bi-level positive airway pressure. Patients with overlap syndrome seem to be ideal candidates for non-invasive ventilation, since they may be chronically hypercapnic and their pulmonary function tests suggest that they could augment ventilation if needed. The effects of bi-level positive airway pressure on overlap syndrome have not been specifically evaluated and whether long-term non-invasive ventilation would improve outcomes in the overlap syndrome, compared to continuous positive airway pressure, is unknown (Owens and Malhotra, 2010). The relationship between the two diseases has not been clarified yet because of the scarcity of the combination of syringomyelia and obstructive sleep apnoea. According to the existing small number of reported cases, the authors speculate that certain relationships may exist between syringomyelia and obstructive sleep apnoea. Syringomyelia can cause obstructive sleep apnoea and obstructive sleep apnoea may in turn promote the progress of syringomyelia. Shiihara et al (1995) reported a case of isolated sleep apnoea caused by syringomyelia. The patient was an 11-year-old girl, 150 cm in height and 49 kg in weight, whose main clinical manifestations were snoring and apnoeic episodes during sleep. She had no blocking or narrowness of the upper airway. Physical examination showed no neurological abnormalities. Blood, electrocardiography, electroencephalography, chest imaging and laryngoscopy examination results were all normal. Magnetic resonance imaging showed syringomyelia at the level of C2–C7. Polysomnography examination showed mixed sleep apnoea–hypopnoea syndrome. The sleep-disordered breathing of the nonobese patient was considered to be caused by syringomyelia. Since no other neurological symptoms and signs existed, sleep apnoea syndrome can be an isolated manifestation of syringomyelia. Ely et al (1994) reported cases which suggested that obstructive sleep apnoea can also become a long-term complication of syringomyelia after surgery. Little research has been carried out to explore the mechanism through which syringomyelia causes obstructive sleep apnoea. Nogués et al (1999) suggested that sleepdisordered breathing may be related to the damage of various nuclei and pathways involved in voluntary and automatic breathing in patients with syringomyelia. Involvement of the ventral and dorsal parts of the spinal cord, the respiratory rhythm generating region, is most important. Other respiratory motor neurons, motor neurons of the diaphragm and intercostal muscles can also be affected through various links, which can lead to abnormal respiratory rhythm during sleep. It seems that sleep-related respiratory disturbances are not the result of respiratory muscle weakness or vocal cord paralysis, and there is no relationship between the severity of the sleeprelated respiratory abnormalities and the size of the cavity.
© 2015 MA Healthcare Ltd
Symposium on The Cardiopulmonary System
British Journal of Hospital Medicine, April 2015, Vol 76, No 4
h Journal of Hospital Medicine. Downloaded from magonlinelibrary.com by 139.080.123.048 on November 27, 2015. For personal use only. No other uses without permission. . All rights rese
Symposium on The Cardiopulmonary System Some case reports suggested that obstructive sleep apnoea could also contribute to the progression of syringomyelia. Pasterkamp et al (1989) reported a case of syringomyelia combined with obstructive sleep apnoea. The patient’s intracranial pressure increased at night when obstructive sleep apnoea occurred. The intracranial pressure increased from 2–5 cmH2O to 50 cmH2O 8–10 seconds after airway obstruction and returned to normal baseline levels when the airway re-opened and breathing recovered. This repeated again and again, with a longest period of 2 minutes. The increase of intracranial pressure, apnoea that lasted longer than 20 seconds, hypopnoea events and severe oxygen desaturation (less than 60%) happened simultaneously. Airway obstruction in this patient was caused by tonsillar hypertrophy, and the obstructive sleep apnoea and periodical increase of intracranial pressure disappeared after tonsillectomy. It was believed that repeated airway obstruction and increased intracranial pressure may promote the progress of syringomyelia in this patient. Nogués et al (1999) also confirmed that increased intracranial pressure caused by obstructive sleep apnoea can lead to acute displacement of cerebellar tonsils and enlargement of the syringomyelia cavity.
Conclusions
This article reported three cases of obstructive sleep apnoea associated with syringomyelia. Although it is possible that the two diseases simply occurred simultaneously in a patient by coincidence, the influence of syringomyelia on the occurrence and development of obstructive sleep apnoea and the effects of obstructive sleep apnoea in worsening syringomyelia should not be neglected. To the authors’ knowledge, this is the first report of obstructive sleep apnoea associated with syringomyelia in Chinese patients. As the condition is rare and the mechanism of the interaction of the two diseases is still unknown, the causal relationship is difficult to judge. Clinicians should be highly vigilant for coexisting obstructive sleep apnoea and syringomyelia. They should make sure that obstructive sleep apnoea is treated effec-
tively as early as possible and at the same time be aware of possible respiratory failure in these patients. As for patients with syringomyelia, especially those who are obese, clinicians should also be alert to the presence of obstructive sleep apnoea. Polysomnography can be carried out if necessary and long-term follow up established to detect obstructive sleep apnoea. BJHM Conflict of interest: none. Ely EW, McCall WV, Haponik EF (1994) Multifactorial obstructive sleep apnea in a patient with Chiari malformation. J Neurol Sci 126(2): 232–6 (doi: 10.1016/0022-510X(94)90280-1) Fletcher EC, Shah A, Qian W, Miller CC 3rd (1991)"Near miss" death in obstructive sleep apnea: a critical care syndrome. Crit Care Med 19(9): 1158–64 Karnik R, Genée P, Ulram A et al (1994) Syringomyelia as a rare cause of respiratory insufficiency requiring ventilation. Dtsch Med Wochenschr 119(51-52): 1771–5 (doi: 10.1055/s-2008-1058899) Masson C, Colombani JM (2005) Chiari type 1 malformation and magnetic resonance imaging. Presse Med 34(21):1662–7 (doi: PM-12-2005-34-21-0755-4982-101019-200509018) Nogués M, Gené R, Benarroch E, Leiguarda R, Calderón C, Encabo H (1999) Respiratory disturbances during sleep in syringomyelia and syringobulbia. Neurology 52(9): 1777–83 (doi: 10.1212/ WNL.52.9.1777) Owens RL, Malhotra A (2010) Sleep-disordered breathing and COPD: the overlap syndrome. Respir Care 55(10): 1333–44 Pasterkamp H, Cardoso ER, Booth FA (1989) Obstructive sleep apnea leading to increased intracranial pressure in a patient with hydrocephalus and syringomyelia. Chest 95(5): 1064–7 (doi: 10.1378/chest.95.5.1064) Pływaczewski R, Korzybski D, Kazanecka B, Jonczak L, Górecka D, Sliwiński P (2009) Resolvement of respiratory failure and polycythemia after CPAP treatment in a middle-aged male with severe obstructive sleep apnea. Pneumonol Alergol Pol 77(5): 479– 83 St Louis EK, Jinnur P, McCarter SJ et al (2014) Chiari 1 malformation presenting as central sleep apnea during pregnancy: a case report, treatment considerations, and review of the literature. Front Neurol 5: 195 (doi: 10.3389/fneur.2014.00195) Shiihara T, Shimizu Y, Mitsui T, Saitoh E, Sato S (1995) Isolated sleep apnea due to Chiari type malformation and syringomyelia. Pediatr Neurol 13(3): 266–7 (doi: 10.1016/08878994(95)00180-N) Verbraecken J, Willemen M, De Cock W, Van de Heyning P, De Backer W (2002) Intermittent positive airway pressure by nasal mask as a treatment for respiratory insufficiency in a patient with syringomyelia. Respiration 69(2): 169–74 (doi: 10.1159/000056322)
LEARNING POINTS ■ Obstructive sleep apnoea is a common disease and syringomyelia is relatively rare. Coexistence of these two diseases is rare.
© 2015 MA Healthcare Ltd
■ This is the first report of patients with obstructive sleep apnoea associated with syringomyelia who do not have Chiari I malformation. ■ There are possible interactions of obstructive sleep apnoea and syringomyelia and they may promote respiratory failure. ■ Clinicians should be highly vigilant for the coexistence of obstructive sleep apnoea and syringomyelia since the outcome may be severe.
British Journal of Hospital Medicine, April 2015, Vol 76, No 4
203
h Journal of Hospital Medicine. Downloaded from magonlinelibrary.com by 139.080.123.048 on November 27, 2015. For personal use only. No other uses without permission. . All rights rese
Obstructive sleep apnoea associated with syringomyelia Coexistence of obstructive sleep apnoea and syringomyelia is quite rare. This article discusses three cases of coexisting obstructive sleep apnoea and syringomyelia and looks at the possible mutual influences between the two diseases.
Cases
Patient 1
A 37-year-old woman who had been in a sudden coma for 1 hour was transferred to the emergency department. The patient had a 5-year history of snoring accompanied by daytime sleepiness and a 5-year history of syringomyelia, neither of which were being treated. On physical examination she was found to be in a light coma with conjunctival oedema. The vital signs were stable. Her body mass index was 28 kg/m2. Arterial blood gas analysis showed pH 7.24, partial pressure of carbon dioxide in arterial blood (PaCO2) 85.2 mmHg and Dr Chuan Shao is Pulmonary Physician in the Department of Respiratory Medicine, Ningbo Medical Treatment Center Li huili Hospital, Ningbo, 315040, China and Professor Shan-qun Li is Pulmonologist and Sleep Specialist in the Department of Pulmonary Disease, Centre of Snoring and Sleep Apnoea Medicine, Zhongshan Hospital, Fudan University, Shanghai, China Correspondence to: Dr C Shao ([email protected])
200
partial pressure of oxygen in arterial blood (PaO2) 98 mmHg (oxygen inhalation through nasal cannulae with 3 litres per minute). The patient recovered consciousness after treatment with intravenous nikethamide and lobeline and subsequently bi-level positive airway pressure was implemented (spontaneous triggering mode/timed safety mode, inspiratory positive airway pressure 16 cmH2O, expiratory positive airway pressure 6 cmH2O, Respironics, Philips, Pittsburgh, Pennsylvania, USA). Arterial blood gas analysis after 4 hours showed pH 7.30, PaCO2 55 mmHg and PaO2 98 mmHg. Polysomnography revealed an apnoea– hypopnoea index of 34.1/hour (mainly obstructive), mean oxyhaemoglobin saturation of 88.1%, and the lowest oxygen saturation of 50%. Long-term home use of bi-level positive airway pressure was started and the patient has been well since.
Patient 2
A 41-year-old woman went to a sleep clinic to seek medical consultation because of ‘snoring and daytime sleepiness’. She had snored loudly during sleep for the last 4 years and had felt daytime sleepiness for the last 2 years. The patient had 5 years’ history of syringomyelia without treatment. She was obese with a body mass index of 30.6 kg/m2. Polysomnography revealed an apnoea– hypopnoea index of 18.5/hour (mainly obstructive), mean oxyhaemoglobin saturation of 87%, and the lowest oxygen saturation of 63%. The patient began long-term home use of nasal continuous positive airway pressure and her symptoms of snoring and daytime sleepiness disappeared after 2 months.
Patient 3
A 35-year-old man went to a sleep clinic for help because of ‘snoring and choking during sleep’. The patient had snored during his sleep for the last 6 years and then felt a choking sensation which could result in awakening from sleep for the past 4 years. Accompanying symptoms included daytime sleepiness and memory loss. The patient had been diagnosed with syringomyelia 5 years earlier and he had undergone an operation for posterior fossa decompression, arachnoid adhesiolysis and spinal
© 2015 MA Healthcare Ltd
O
bstructive sleep apnoea is characterized by recurrent obstruction or collapse of the upper airway during sleep, which induces intermittent hypoxia and hypercapnia. Obstructive sleep apnoea is a major predisposing factor for systemic conditions, such as hypertension, cardiovascular disease, stroke and diabetes, so it is not unusual to find obstructive sleep apnoea accompanying various diseases in a single patient. However, obstructive sleep apnoea is a relatively rare comorbidity in patients who have syringomyelia. Syringomyelia is a rare disease with poor treatment outcomes. It is pathologically characterized by the presence of long cavities, surrounded by gliosis, in the central part of the spinal cord (Verbraecken et al, 2002). Clinical manifestations include muscle atrophy, loss of pain and temperature sensation, limb paralysis and nutrition disorders. This article reports three cases of obstructive sleep apnoea associated with syringomyelia, discusses possible pathophysiological relationships between the two diseases, and reviews the literature concerning concurrence of obstructive sleep apnoea and syringomyelia.
British Journal of Hospital Medicine, April 2015, Vol 76, No 4
h Journal of Hospital Medicine. Downloaded from magonlinelibrary.com by 139.080.123.048 on November 27, 2015. For personal use only. No other uses without permission. . All rights rese
Symposium on The Cardiopulmonary System cord cavity shunt in another hospital 5 years ago under general anaesthesia. Cervical sagittal magnetic resonance imaging of the patient before and after surgery is shown in Figure 1. Physical examination showed left facial hypoalgesia, grade IV muscle strength of the right forearm, and surgical scars on his neck and right forearm. The patient’s body mass index was 22.9 kg/m2. Polysomnography revealed an apnoea–hypopnoea index of 113.5/hour (mainly obstructive), mean oxyhaemoglobin saturation of 91.4%, and the lowest oxygen saturation of 78%. The original waveform of his overnight polysomnography is shown in Figure 2 and the summary chart in Figure 3. The patient was treated with continuous positive airway pressure: the symptoms of snoring and choking disappeared and his overnight oxygen saturation returned to normal after treatment. The patient began long-term home use of nasal continuous positive airway pressure and has subsequently remained well.
© 2015 MA Healthcare Ltd
Discussion
Syringomyelia is detected in 32–74% of patients with a Chiari I malformation (Masson and Colombani, 2005) and Chiari I malformation frequently causes obstructive or central sleep-disordered breathing and potentially serious disturbances such as respiratory failure, syncope and even sudden death (St Louis et al, 2014). So obstructive sleep apnoea in some syringomyelia patients could be caused by the combined effect of craniovertebral junction malformation. This article has reported three cases of obstructive sleep apnoea with syringomyelia but without Chiari I malformation and focusses on the relationship between obstructive sleep apnoea and simple syringomyelia. Syringomyelia, obstructive sleep apnoea and coexistence of the two diseases can all lead to respiratory failure. Syringomyelia is a rare cause of respiratory failure. The specific mechanism may be related to flaccid paralysis of the respiratory muscles of the chest wall (Karnik et al, 1994) because the spinal cord, as an important respiratory centre, contains motor neurons in the anterior horn that stimulate the respiratory muscles. For example, at the C3–C5 level the spinal cord stimulates the diaphragm and at the thoracic level it stimulates the intercostal and abdominal muscles. Obstructive sleep apnoea can also lead to respiratory failure, especially in obese patients with severe hypoxaemia at night (Karnik et al, 1994). Respiratory failure induced by obstructive sleep apnoea has also been called ‘near miss’ death syndrome. Patients with obstructive sleep apnoea who have hypoxaemia and hypercapnia are more likely to develop severe respiratory failure and even death than those simply with hypoxaemia. Recurrent respiratory failure of near miss death syndrome can be reversed by effective treatment of obstructive sleep apnoea (Fletcher et al, 1991). British Journal of Hospital Medicine, April 2015, Vol 76, No 4
Figure 1. Cervical sagittal magnetic resonance imaging of patient 3 before and after his operation. a. Magnetic resonance imaging showed low T1 signal in the lower medulla oblongata and cervical spinal cord, cervical magnetic resonance imaging showed spinal cord central canal expansion below the level of C2. b. Magnetic resonance imaging showed postoperative changes.
Figure 2. Original waveform of night polysomnography of patient 3. The green wave shows nasal airflow and the yellow wave shows abdominal movement when breathing. The parts of the green wave in the pink areas indicate the suspension of nasal airflow when abdominal movement remained, suggesting obstructive sleep apnoea.
Pływaczewski et al (2009) reported a case of respiratory failure caused by severe obstructive sleep apnoea. The patient was a 52-year-old man with body mass index of 46.2 kg/m2, first diagnosed as having ‘respiratory failure and polycythaemia’. Polysomnography showed the respiratory disturbance index was 60/hour. Arterial blood gas indices gradually returned to normal during effective auto-continuous positive airway pressure treatment. After 1 month of auto-continuous positive airway pressure treatment at home, the blood morphology and PaCO2 201
h Journal of Hospital Medicine. Downloaded from magonlinelibrary.com by 139.080.123.048 on November 27, 2015. For personal use only. No other uses without permission. . All rights rese
Figure 3. Summary chart of polysomnography results of patient 3. Horizontal axis represents time and vertical axis represents polysomnography parameters. Equipment was the nine lead Embletta PDS from ResMed, Australia.
returned to normal and the patient’s oxygenation status improved too. Verbraecken et al (2002) reported a case of a patient with syringomyelia and sleep apnoea who also had chronic respiratory failure. The patient’s condition improved quickly and significantly with use of noninvasive ventilation. The patient’s exercise tolerance and degree of arousal increased while hypercapnia and hypoxaemia disappeared. Mechanical ventilation at night helped to restore the patient’s respiratory drive during the daytime, to correct hypoxia, and improve heart function at the same time. However, in the first of the current patients, a high PaCO2 and a good response to treatment with respiratory stimulants indicated decreased respiratory muscle strength. The authors can not rule out a likely diagnosis of chronic obstructive pulmonary disease without the results of pulmonary function tests, so the diagnosis of overlap syndrome may be more accurate for this patient. In this case, type 2 respiratory failure may be caused largely by obstructive ventilation dysfunction and respiratory muscle fatigue. Continuous positive airway pressure remains the accepted standard treatment for obstructive sleep apnoea and overlap syndrome. The first 202
patient was treated successfully with bi-level positive airway pressure. Patients with overlap syndrome seem to be ideal candidates for non-invasive ventilation, since they may be chronically hypercapnic and their pulmonary function tests suggest that they could augment ventilation if needed. The effects of bi-level positive airway pressure on overlap syndrome have not been specifically evaluated and whether long-term non-invasive ventilation would improve outcomes in the overlap syndrome, compared to continuous positive airway pressure, is unknown (Owens and Malhotra, 2010). The relationship between the two diseases has not been clarified yet because of the scarcity of the combination of syringomyelia and obstructive sleep apnoea. According to the existing small number of reported cases, the authors speculate that certain relationships may exist between syringomyelia and obstructive sleep apnoea. Syringomyelia can cause obstructive sleep apnoea and obstructive sleep apnoea may in turn promote the progress of syringomyelia. Shiihara et al (1995) reported a case of isolated sleep apnoea caused by syringomyelia. The patient was an 11-year-old girl, 150 cm in height and 49 kg in weight, whose main clinical manifestations were snoring and apnoeic episodes during sleep. She had no blocking or narrowness of the upper airway. Physical examination showed no neurological abnormalities. Blood, electrocardiography, electroencephalography, chest imaging and laryngoscopy examination results were all normal. Magnetic resonance imaging showed syringomyelia at the level of C2–C7. Polysomnography examination showed mixed sleep apnoea–hypopnoea syndrome. The sleep-disordered breathing of the nonobese patient was considered to be caused by syringomyelia. Since no other neurological symptoms and signs existed, sleep apnoea syndrome can be an isolated manifestation of syringomyelia. Ely et al (1994) reported cases which suggested that obstructive sleep apnoea can also become a long-term complication of syringomyelia after surgery. Little research has been carried out to explore the mechanism through which syringomyelia causes obstructive sleep apnoea. Nogués et al (1999) suggested that sleepdisordered breathing may be related to the damage of various nuclei and pathways involved in voluntary and automatic breathing in patients with syringomyelia. Involvement of the ventral and dorsal parts of the spinal cord, the respiratory rhythm generating region, is most important. Other respiratory motor neurons, motor neurons of the diaphragm and intercostal muscles can also be affected through various links, which can lead to abnormal respiratory rhythm during sleep. It seems that sleep-related respiratory disturbances are not the result of respiratory muscle weakness or vocal cord paralysis, and there is no relationship between the severity of the sleeprelated respiratory abnormalities and the size of the cavity.
© 2015 MA Healthcare Ltd
Symposium on The Cardiopulmonary System
British Journal of Hospital Medicine, April 2015, Vol 76, No 4
h Journal of Hospital Medicine. Downloaded from magonlinelibrary.com by 139.080.123.048 on November 27, 2015. For personal use only. No other uses without permission. . All rights rese
Symposium on The Cardiopulmonary System Some case reports suggested that obstructive sleep apnoea could also contribute to the progression of syringomyelia. Pasterkamp et al (1989) reported a case of syringomyelia combined with obstructive sleep apnoea. The patient’s intracranial pressure increased at night when obstructive sleep apnoea occurred. The intracranial pressure increased from 2–5 cmH2O to 50 cmH2O 8–10 seconds after airway obstruction and returned to normal baseline levels when the airway re-opened and breathing recovered. This repeated again and again, with a longest period of 2 minutes. The increase of intracranial pressure, apnoea that lasted longer than 20 seconds, hypopnoea events and severe oxygen desaturation (less than 60%) happened simultaneously. Airway obstruction in this patient was caused by tonsillar hypertrophy, and the obstructive sleep apnoea and periodical increase of intracranial pressure disappeared after tonsillectomy. It was believed that repeated airway obstruction and increased intracranial pressure may promote the progress of syringomyelia in this patient. Nogués et al (1999) also confirmed that increased intracranial pressure caused by obstructive sleep apnoea can lead to acute displacement of cerebellar tonsils and enlargement of the syringomyelia cavity.
Conclusions
This article reported three cases of obstructive sleep apnoea associated with syringomyelia. Although it is possible that the two diseases simply occurred simultaneously in a patient by coincidence, the influence of syringomyelia on the occurrence and development of obstructive sleep apnoea and the effects of obstructive sleep apnoea in worsening syringomyelia should not be neglected. To the authors’ knowledge, this is the first report of obstructive sleep apnoea associated with syringomyelia in Chinese patients. As the condition is rare and the mechanism of the interaction of the two diseases is still unknown, the causal relationship is difficult to judge. Clinicians should be highly vigilant for coexisting obstructive sleep apnoea and syringomyelia. They should make sure that obstructive sleep apnoea is treated effec-
tively as early as possible and at the same time be aware of possible respiratory failure in these patients. As for patients with syringomyelia, especially those who are obese, clinicians should also be alert to the presence of obstructive sleep apnoea. Polysomnography can be carried out if necessary and long-term follow up established to detect obstructive sleep apnoea. BJHM Conflict of interest: none. Ely EW, McCall WV, Haponik EF (1994) Multifactorial obstructive sleep apnea in a patient with Chiari malformation. J Neurol Sci 126(2): 232–6 (doi: 10.1016/0022-510X(94)90280-1) Fletcher EC, Shah A, Qian W, Miller CC 3rd (1991)"Near miss" death in obstructive sleep apnea: a critical care syndrome. Crit Care Med 19(9): 1158–64 Karnik R, Genée P, Ulram A et al (1994) Syringomyelia as a rare cause of respiratory insufficiency requiring ventilation. Dtsch Med Wochenschr 119(51-52): 1771–5 (doi: 10.1055/s-2008-1058899) Masson C, Colombani JM (2005) Chiari type 1 malformation and magnetic resonance imaging. Presse Med 34(21):1662–7 (doi: PM-12-2005-34-21-0755-4982-101019-200509018) Nogués M, Gené R, Benarroch E, Leiguarda R, Calderón C, Encabo H (1999) Respiratory disturbances during sleep in syringomyelia and syringobulbia. Neurology 52(9): 1777–83 (doi: 10.1212/ WNL.52.9.1777) Owens RL, Malhotra A (2010) Sleep-disordered breathing and COPD: the overlap syndrome. Respir Care 55(10): 1333–44 Pasterkamp H, Cardoso ER, Booth FA (1989) Obstructive sleep apnea leading to increased intracranial pressure in a patient with hydrocephalus and syringomyelia. Chest 95(5): 1064–7 (doi: 10.1378/chest.95.5.1064) Pływaczewski R, Korzybski D, Kazanecka B, Jonczak L, Górecka D, Sliwiński P (2009) Resolvement of respiratory failure and polycythemia after CPAP treatment in a middle-aged male with severe obstructive sleep apnea. Pneumonol Alergol Pol 77(5): 479– 83 St Louis EK, Jinnur P, McCarter SJ et al (2014) Chiari 1 malformation presenting as central sleep apnea during pregnancy: a case report, treatment considerations, and review of the literature. Front Neurol 5: 195 (doi: 10.3389/fneur.2014.00195) Shiihara T, Shimizu Y, Mitsui T, Saitoh E, Sato S (1995) Isolated sleep apnea due to Chiari type malformation and syringomyelia. Pediatr Neurol 13(3): 266–7 (doi: 10.1016/08878994(95)00180-N) Verbraecken J, Willemen M, De Cock W, Van de Heyning P, De Backer W (2002) Intermittent positive airway pressure by nasal mask as a treatment for respiratory insufficiency in a patient with syringomyelia. Respiration 69(2): 169–74 (doi: 10.1159/000056322)
LEARNING POINTS ■ Obstructive sleep apnoea is a common disease and syringomyelia is relatively rare. Coexistence of these two diseases is rare.
© 2015 MA Healthcare Ltd
■ This is the first report of patients with obstructive sleep apnoea associated with syringomyelia who do not have Chiari I malformation. ■ There are possible interactions of obstructive sleep apnoea and syringomyelia and they may promote respiratory failure. ■ Clinicians should be highly vigilant for the coexistence of obstructive sleep apnoea and syringomyelia since the outcome may be severe.
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