Kumar S P, Sword D, Petty R K H, Banham S W, Patel K R
Department of Respiratory Medicine, Gartnavel General Hospital, Glasgow, UK.
Chron Respir Dis. 2007;4(1):15-8. doi: 10.1177/1479972306074480.
Myotonic dystrophy (MD) is the commonest adult muscular dystrophy and is associated with respiratory muscle weakness. The role of screening sleep studies is unclear in MD. We prospectively evaluated polysomnography/overnight oximetry in a group of MD patients and related this to the daytime respiratory function in an attempt to evaluate the usefulness of screening sleep studies. Twenty-five patients with type I MD [15 males; mean age (SD) 40.0 (10.9) years] who had at least one symptom suggestive of nocturnal hypoventilation were included in the study. We performed spirometry, maximal inspiratory and expiratory mouth pressures, sniff nasal inspiratory pressure, arterial blood gases and polysomnography or overnight oximetry. Excessive tiredness and sleepiness were the most common presenting symptoms. Prevalence of sleep related breathing disorder (SRBD) was 36%. FVC was found to be normal in 33% of subjects with significant SRBD. Mouth pressures were reduced more than FVC, even in patients with normal overnight oxygen saturation. Of all the daytime measures, FVC correlated best with arterial carbon dioxide tension (r = -0.7). Sleep studies were useful to identify a small group of myotonic dystrophy patients (12%, three out of 25 in our series) with SRBD that would have been missed with routine daytime assessments. Targeted sleep monitoring in patients who are older, with multiple symptoms suggestive of SRBD, especially if they are overweight seems to be the best way to utilize the existing resources. Home unattended oximetry was well tolerated and offers a practical screening tool in this challenging patient group where excess daytime sleepiness is often due to causes other than SRBD.
强直性肌营养不良（MD）是最常见的成人肌肉营养不良症，与呼吸肌无力有关。在MD中，筛查睡眠研究的作用尚不清楚。我们前瞻性地评估了一组MD患者的多导睡眠图/夜间血氧饱和度测定，并将其与白天的呼吸功能相关联，以评估筛查睡眠研究的有用性。本研究纳入了25例I型MD患者[15例男性；平均年龄（标准差）40.0（10.9）岁]，这些患者至少有一种提示夜间通气不足的症状。我们进行了肺活量测定、最大吸气和呼气口腔压力、嗅鼻吸气压力、动脉血气分析以及多导睡眠图或夜间血氧饱和度测定。过度疲劳和嗜睡是最常见的症状。睡眠相关呼吸障碍（SRBD）的患病率为36%。在有明显SRBD的受试者中，33%的人用力肺活量（FVC）正常。即使夜间血氧饱和度正常的患者，口腔压力下降也比FVC更明显。在所有白天的测量指标中，FVC与动脉血二氧化碳分压的相关性最好（r = -0.7）。睡眠研究有助于识别一小部分强直性肌营养不良患者（12%，我们系列中的25例中有3例）患有SRBD，而这些患者通过常规白天评估会被漏诊。对于年龄较大、有多种提示SRBD症状的患者，尤其是超重患者，针对性的睡眠监测似乎是利用现有资源的最佳方法。家庭无人值守的血氧饱和度测定耐受性良好，为这个具有挑战性的患者群体提供了一种实用的筛查工具，在这个群体中，白天过度嗜睡往往是由SRBD以外的原因引起的。
