Screening and diagnosis
Your doctor may make an evaluation based on your signs and symptoms or may refer you to a sleep disorder center. There, a sleep specialist can help you decide on your need for further evaluation. Such an evaluation often involves overnight monitoring of your breathing and other body functions during sleep. Tests to detect sleep apnea may include:
• Nocturnal polysomnography. During this test, you're hooked up to equipment that monitors your heart, lung and brain activity, breathing patterns, arm and leg movements, and blood oxygen levels while you sleep. Because treatments for other sleep disorders such as narcolepsy and insomnia differ, this test helps your doctor to arrive at an accurate diagnosis.
• Oximetry. This screening method involves using a small machine that monitors and records your oxygen level while you're asleep. A simple sleeve fits painlessly over one of your fingers to collect the information overnight at home. If you have sleep apnea, the results of this test will show drops in your oxygen level during apneas and subsequent rises with awakenings. If the results are abnormal, your doctor may have you undergo polysomnography to confirm the diagnosis. Oximetry doesn't detect all cases of sleep apnea, so your doctor may still recommend a polysomnogram even if the oximetry results are normal.
• Portable cardiorespiratory testing. Under certain circumstances, your doctor may provide you with simplified tests to be used at home to diagnose sleep apnea. These tests usually involve oximetry, measurement of airflow and measurement of breathing patterns.
If you have obstructive sleep apnea, your doctor may refer you to an ear, nose and throat doctor (otolaryngologist) to rule out any blockage in your nose or throat. An evaluation by a heart doctor (cardiologist) or a doctor who specializes in the nervous system (neurologist) may be necessary to look for causes of central sleep apnea.
Complications
Sleep apnea is considered a serious medical condition. Complications may include:
• Cardiovascular problems. Sudden drops in blood oxygen levels that occur during sleep apnea increase blood pressure and strain the cardiovascular system. About half of people with sleep apnea develop high blood pressure (hypertension), which raises the risk of heart failure and stroke. If there's underlying heart disease, these repeated multiple episodes of low blood oxygen (hypoxia or hypoxemia) can lead to sudden death from a cardiac event.
The more severe the obstructive sleep apnea, the greater the risk for high blood pressure. In contrast, central sleep apnea usually is the result, rather than the cause, of heart disease.
A study published in November 2005 in the New England Journal of Medicine reported that obstructive sleep apnea greatly increases the risk of stroke, regardless of whether a person has high blood pressure. However, effectively treating obstructive sleep apnea can lower blood pressure and the risk of other cardiovascular diseases.
• Daytime fatigue. The repeated awakenings associated with sleep apnea make normal, restorative sleep impossible. People with sleep apnea often experience severe daytime drowsiness, fatigue and irritability. They may have difficulty concentrating and find themselves falling asleep at work, while watching TV or even when driving. Children and young people with sleep apnea may do poorly in school or have behavior problems.
• Complications with medications and surgery. Obstructive sleep apnea also is a concern with certain medications and general anesthesia. People with sleep apnea may be more likely to experience complications following major surgery because they're prone to breathing problems, especially when sedated and lying on their backs. Before you have surgery, tell your doctor that you have sleep apnea. Undiagnosed sleep apnea is especially risky in this situation.
• Sleep-deprived partners. Loud snoring can keep those around you from getting good rest and eventually disrupt your relationships. It's not uncommon for a bed partner to sleep in another room, or even on another floor of the house, to be able to sleep. Many bed partners of people who snore are sleep deprived as well.
People with obstructive and central sleep apneas may also complain of memory problems, morning headaches, mood swings or feelings of depression, a need to urinate frequently at night (nocturia), and impotence. Gastroesophageal reflux disease (GERD) may be more prevalent in people with sleep apnea. Children with untreated sleep apnea may be hyperactive and may be diagnosed with attention-deficit/hyperactivity disorder (ADHD).
