睡眠醫學二十一之睡眠窒息症與久咳都有關係?
自己從前多數照顧住院病人，現在大部份時間行醫卻以門診為主，因此亦接觸了以前較少處理的病例-久咳。醫學上稱持續八星期之上的咳嗽為久咳[Chronic cough] ，而久咳最常見的三大病因是胃酸倒流[Gastro-oesophageal
reflux disease] 、鼻水倒流[ upper airway cough syndrome] 和哮喘類[ cough variant asthma]。最近遇到一個患上久咳的病人，可能他的問題持續了太長，因此他四出查考各種可能性，在診症的末段，他竟然問我睡眠窒息症與久咳有沒有關係。幸好我在出版「肺苦之言」一書時曾經查考過相關資料。
在2007年才有學者首次懷疑睡眠窒息症[OSA]與久咳[CHRONIC COUGH]有關係[1] ，那麼這種配搭[OSA + Chronic cough] 是否常見呢 ? 在一個小型[只有75位病人]社區研究[2] 發現約四成半的久咳病人有睡眠窒息症，而另一個研究發現99位睡眠窒息症病人中有39位同時有久咳[3] ，亦有零星的小型研究[17,20,22] 匯報這種疾病的關係。進一步研究發現女士多於男士同時患上睡眠窒息症加久咳[4,5,6]，而同時患上這兩種疾病的人通常有較高的Body Mass Index,
BMI[[4,5,6]，但這兩種疾病的病情並不掛鈎或成比例[20]。
為何睡眠窒息症[OSA]與久咳[CHRONIC COUGH]扯上關係? 原因可能是:1] 較多睡眠窒息症病人有胃酸倒流問題，而持續正氣壓機[CPAP] 正正能減少胃酸倒流[7] 、2] 上呼吸道受創[upper
airway and laryngeal trauma]- 睡眠窒息症病人常有聲帶問題[8,9] 、3] 下呼吸道發炎[lower airway inflammation]-久咳的病人原本就有下呼吸道發炎，而睡眠窒息會加劇下氣道發炎[10,11] 、4] 上呼吸道感染風險增加[increased risks of colds & upper respiratory infections]- 睡眠不足令人較易患上上呼吸道感染[12] ，而久咳的病人在感染後又再處於過敏狀態[cough
hypersensitivity state]。當然不同學者對其病理會有不同的推論[13,18]。
某些國家級關於咳嗽的醫學指引[Cough
guidelines]已經將睡眠窒息症列入久咳其中一個病因，如澳州[14] 及韓國[15]。但能在久咳病人中診斷出睡眠窒息症對病人有沒有幫助呢? 不少研究都同樣發現此等病人使用持續正氣壓機[CPAP] 後，不但控制了睡眠窒息症，也同時減輕了久咳的病情[2, 16, 17,18,19,21,22]。
越來越發覺學海無涯!
參考文獻:
1.
Obstructive sleep apnoea:
a cause of chronic cough. Cough 2007;3:7
2.
chronic
cough and obstructive sleep apnea in a community-based pulmonary practice. Cough 2010, 6:2
3.
Chronic cough and
obstructive sleep apnoea in a sleep laboratory-based pulmonary practice. Cough 2013, 9:24
4.
Chronic cough and
obstructive sleep apnea in a community-based practice. Cough 2010;6:2
5.
Chronic cough in patients
with sleep-disordered breathing. Eur
Respir J 2010;35:368–372
6.
A longitudinal study of
CPAP therapy for chronic cough patients with obstructive sleep apnoea. Cough 2013;9:19
7.
Chronic cough and
obstructive sleep apnoea: reflux-associated cough hypersensitivity? Eur Respir J 2012 40:1049–1050
8.
Refractory chronic cough,
or the need to focus on the relationship between the larynx and the esophagus. Cough 2013; 9:10
9.
Laryngeal and
velopharyngeal sensory impairment in obstructive sleep apnea. Sleep 2005;28:585–593
10.
Reduced pH and chloride
levels in exhaled breath condensate of patients with chronic cough. Thorax 2004;59:608–612
11.
Airway wall thickening in
patients with cough variant asthma and nonasthmatic chronic cough. Chest 2007;131:1042–1049
12.
Sleep habits and
susceptibility to common cold. Arch
Intern Med 2009;169:62–67
13.
Chronic Cough and OSA: A new Association? J Clin Sleep Med 2011;7(6):669-677.
14.
CICADA: Cough in
Children and Adults: Diagnosis and Assessment. Australian Cough Guidelines
summary statement. MJA 2010; 192: 265–271
15.
The Korean Cough Guideline: Recommendation and Summary Statement. Tuberc Respir Dis
2016;79:14-21
16.
Suppresion of
chronic nocturnal cough during continuous positive airway pressure (CPAP)
treatment in a patient with asthma and obstructive sleep apnoea syndrome. Pneumonol. Alergol. Pol. 2011; 79, 2: 121–126
17.
Obstructive sleep apnea-induced chronic cough: Three case reports and a
review of the literature. International
Journal of Clinical and Experimental Medicine. 2017.; 10 (8) (pp 12733-12741),
18.
Cough in obstructive sleep apnoea. Pulmonary
Pharmacology and Therapeutics. 2015;35 (pp 129-131)
19.
The utility of continuous positive airway pressure therapy for treating
chronic coughs in patients with obstructive sleep apnea. American Journal of Respiratory and Critical Care Medicine. Conference:
American Thoracic Society International.Conference, ATS 2014. San Diego, CA
United States. Conference Publication: (var.pagings). 189 (no pagination),
2014.
20.
Chronic cough and OSA in patients undergoing polysomnography: A cross
sectional study. Sleep and Biological
Rhythms. Conference: 26th ASM of Australasian Sleep Association and
Australasian Sleep Technologists Association: Sleep Frontiers, Sleep DownUnder
2014. Perth, WA Australia. Conference Publication: (var.pagings). 12 (pp 14),
2014. Date of Publication: October 2014. AN: 71747968
21.
Impact of continuous positive airway pressure (CPAP) on chronic cough in
obstructive sleep apnoea (OSA)-a randomized controlled trial. Journal of Sleep Research. Conference: 22nd
Congress of the European Sleep Research Society. Tallinn Estonia. Conference Publication:
(var.pagings). 23 (pp 153), 2014. Date of Publication: September 2014. AN: 71715379
22. Prospective study of the
prevalence of obstructive sleep apnea (OSA) in patients with chronic cough and
impact of nocturnal continuous positive airway pressure therapy (CPAP) on the
course of chronic cough. Chest.
Conference: CHEST 2012. Atlanta, GA United States. Conference Publication:
(var.pagings). 142 (4 SUPPL. 1) (no pagination), 2012. Date of Publication:
October 2012. AN: 71073391
