Obstructive sleep apnea (OSA) is a disorder characterized by airway collapse leading to episodes of breathing cessation. In North America, approximately 15 to 30 percent of males and 10 to 15 percent of females have a diagnosis of obstructive sleep apnea. It is more prevalent in those who are in their 60s to 70s, are male and are obese. However, OSA is also more common in those with a large neck and/or waist circumference than general habitus obesity. Some clinical features of individuals who have OSA include daytime sleepiness, loud snoring, choking or gasping during sleep, morning headaches and even nocturia. A crowded oropharyngeal airway can cause a narrowed upper airway and contribute to the development of OSA. This includes retrognathia, micrognathia, lateral peritonsillar narrowing, or an elongated or enlarged uvula. Prior to officially diagnosing a patient with OSA, clinicians should be exploring other differential diagnoses including primary snoring, gastroesophageal reflux disease and nocturnal asthma. Some evaluation tools include the STOP-Bang questionnaire or Epworth Sleepiness Scale. These help to select those at risk for OSA to then go for a sleep study where they will receive a polysomnography. In-laboratory polysomnography is considered the gold standard diagnostic test for OSA.
Usually positive airway pressure (PAP) is the first line treatment for OSA but poor tolerance and low adherence to PAP therapy is a major barrier and leave many patients untreated. For patients who are noncompliant or decline PAP, hypoglossal nerve stimulation (HNS) is being increasingly used as therapy. The HNS device is implanted in the neck crease of the submandibular area. During sleep, the HNS device activates upper airway muscles, specifically the genioglossus muscle, which produces tongue protrusion. In order to avoid genioglossus muscle fatigue, the device only creates neurostimulation at the initiation of each breath. Indications for HNS therapy are only for adults over 18 years old, diagnosis of moderate to severe OSA, failure or intolerance of PAP therapy, BMI of less than 40, and absence of collapse at the velopharynx or soft palate on drug-induced sleep endoscopy. It is contraindicated in those who have severe cardiac or pulmonary conditions, those who are pregnant and have active and uncontrolled sleep disorders. Typically after implantation, it is standard of care to get an anterior-posterior chest and lateral neck radiograph to rule out a pneumothorax and document the baseline position of the device. One week after the procedure, patients are assessed for wound healing and other adverse events such as tongue and lip weakness, asymmetric smile, infection, hematoma or pain. The HNS device is activated four weeks after implant placement and set on the lowest amplitude. Patient education is provided on self-titration and asked to use the device nightly. For patients with suboptimal response to the device, clinicians assess and treat and perform any device setting adjustments as needed.
The prompt treatment of obstructive sleep apnea is extremely important due to the negative clinical outcomes that are possible. OSA can worsen attention, memory and cause cognitive deficits which can increase risks of depression, psychosis and sexual dysfunction. Patients with untreated OSA are at a two times higher risk for motor vehicle accidents as well. In addition, patients are at a higher risk for systemic hypertension, coronary artery disease, cardiac arrhythmias, heart failure and stroke. They also have an increased prevalence of insulin resistance as well as type II diabetes and complications of diabetes. The link between obstructive sleep apnea to a multitude of conditions makes it all the more important for clinicians to screen their patients and test those that are at high risk. For those that fail PAP, hypoglossal nerve stimulation devices should be an option as they are important in addressing untreated obstructive sleep apnea.
Resources:
https://www.uptodate.com/contents/clinical-presentation-and-diagnosis-of-obstructive-sleep-apnea-in-adults?search=sleep%20apnea&source=search_result&selectedTitle=1%7E150&usage_type=default&display_rank=1 Assessed and Endorsed by the MedReport Medical Review Board