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Pediatric T2DM: A Growing Threat to US Health
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CLINICAL EVALUATION
Patient History
Clinicians become aware of patients with OSA when they present with associated symptoms or complications. These symptoms are encountered in several settings—as a part of the routine health maintenance examination, as the patient’s presenting complaint, or as a part of the evaluation for another complaint or medical condition.
Regardless of how the symptoms are discovered, all patients with symptoms of and/or positive risk factors for OSA should be assessed via a comprehensive sleep oriented history and physical examination. Symptoms suggestive of OSA include witnessed or reported apneas, snoring, gasping/choking at night, excessive daytime sleepiness not explained by other factors, severity of sleepiness (as determined by the Epworth Sleepiness Scale), nonrefreshing sleep, sleep fragmentation/maintenance insomnia, nocturia, morning headaches, decreased concentration, memory loss, decreased libido, and irritability.10 A recently published study found that nocturnal gasping or choking is the most reliable indicator for identifying patients with OSA.11
The clinical presentation of OSA in certain populations may differ from that of typical adult OSA, requiring a higher degree of clinical suspicion. For instance, pediatric OSA should be suspected in any child who presents with enuresis, poor school performance, failure to thrive, attention-deficit/hyperactivity disorder, or learning disabilities.9 Alternatively, females with OSA have a propensity to emphasize complaints of tiredness, fatigue, or lack of energy rather than report excessive sleepiness per se. These complaints frequently misdirect clinicians toward psychiatric and endocrine diagnoses, without considering the possibility of a sleep disorder.12
Risk Factors
In addition to symptomatology, there are several risk factors associated with OSA that should be considered. The most important are male gender, increasing age (40 to 70), obesity, large neck circumference, and craniofacial and upper airway abnormalities.13 Among the intermediate risk factors are family history of OSA, pregnancy, and Hispanic, Asian, and African-American ethnicity.
Other risk factors associated with OSA include cigarette smoking, alcohol use before sleep, and use of sedative medications.13 Comorbid medical conditions have also been shown to exacerbate and to contribute to OSA; these include GERD, diabetes, congestive heart failure, treatment-refractory hypertension, hypothyroidism, acromegaly, atrial fibrillation, stroke, Down syndrome (due to macroglossia), and pulmonary hypertension.4,10
Screening Questionnaires
Several questionnaires have been validated to screen for OSA. They can be used clinically as part of the sleep-oriented history to quantify a patient’s subjective complaint of sleepiness; however, they are typically more helpful for ruling out sleep apnea than for diagnosing it.11 Two of the most commonly utilized are the Epworth Sleepiness Scale (ESS; http://epworthsleepinessscale.com/epworth-sleepiness-scale.pdf) and the Berlin Questionnaire (www.sleepapnea.org/assets/files/pdf/Berlin%20Questionnaire.pdf).
The ESS was developed to identify patients with excessive daytime sleepiness. It asks patients to rate—on a scale of 0 (would never doze) to 4 (high chance of dozing)—how likely they are to doze off or fall asleep during eight everyday scenarios (ie, sitting and reading; watching TV; sitting inactive in a public place; being a passenger in a vehicle for one or more hours; lying down in the afternoon; sitting and talking to someone; sitting quietly after lunch; or while stopped for a few minutes while driving in traffic).14 The total score can range from 0 to 24. Patients scoring higher than 10 should be referred to a sleep specialist. The ESS can be used to detect symptoms suggestive of OSA; however, it is not specific to OSA and was designed to screen for all sleep disorders.14
In contrast, the Berlin Questionnaire consists of 10 questions that quantify and qualify a patient’s snoring and sleepiness, and it was developed specifically to evaluate for OSA. The questionnaire measures three categories of symptoms: snoring, fatigue, and blood pressure and BMI. A patient is deemed at high risk for OSA when scoring positive in two or more symptom categories, and at low risk when scoring positive in one category.15 However, when OSA is defined as an AHI of ≥ 5 events/hr, the Berlin Questionnaire is 80% sensitive and 46% specific for OSA.11 Therefore, screening questionnaires are useful as supplementary tools but are of limited utility as the sole method for evaluating and diagnosing OSA.
Physical Examination
Physical examination should include assessment for risk factors and comorbidities associated with OSA; this includes measurement of blood pressure, blood glucose, and neck circumference; calculation of BMI and waist-to-hip ratio; and assessment for craniofacial abnormalities. Additionally, cardiovascular, respiratory, and neurologic systems should be evaluated for potential alterations due to OSA.10
Physical exam findings suggestive of OSA are BMI ≥ 30, neck circumference > 17 in for males and > 16 in for females, and craniofacial and upper airway abnormalities. Such anatomic variations include retrognathia, macroglossia (eg, Down syndrome patients), tonsillar hypertrophy (eg, pediatric patients), lateral peritonsillar narrowing, high-arched or narrow hard palate, enlarged uvula, nasal polyps, nasal deviation, turbinate hypertrophy, and oropharynx anatomy consistent with modified Mallampati class III or IV.10 Although OSA is more prevalent in obese patients (those with a BMI ≥ 30), it should be noted that 14.6% of OSA patients are normal weight (BMI < 25) and 34.5%, overweight (BMI 25 to 30).16
The modified Mallampati classification is a straightforward scoring method that was designed to estimate the difficulty of oral intubation based on the extent of mouth opening relative to the size of the tongue.17 According to the protocol set forth by Mallampati and colleagues, assessment is performed with the patient sitting upright with the head in a neutral position, the mouth open, and the tongue maximally protruded without the patient speaking or saying “ahh.”18 The examiner then inspects the pharyngeal structures and classifies the patient’s airway according to the structures visualized. Class I is present when the soft palate, uvula, and pillars are visible; class II when the soft palate and uvula are visible; class III when the soft palate and base of the uvula are visible; class IV when the soft palate is not visible at all (see Figure 1).17,18
An alternative method for observing the pharyngeal structures is via nasopharyngoscopy.19 This procedure can be done in the office setting and utilizes a flexible scope inserted into the nasal cavity and advanced into the pharynx. By providing direct visualization of the upper airway structures, nasopharyngoscopy allows the operator to determine the extent and the location of airway collapse. Imaging by nasopharyngoscopy does not involve any radiation exposure and can be done while the patient is sedated or awake.19
LABORATORY WORKUP AND DIAGNOSIS
Patients deemed high-risk by the sleep-oriented history and physical examination should be subsequently referred to a sleep specialist for objective testing to establish the diagnosis and determine the severity of OSA. Despite the utilization of screening questionnaires, currently there is no consensus on risk stratification to determine when to refer patients with suspected OSA. In other words, no clear thresholds exist on whether a patient is at “low risk” or at “high risk” for OSA based on history and physical examination findings. Therefore, referral is made at the clinician’s discretion, based on the number and severity of OSA symptoms and risk factors.
There are two standard objective sleep study tests: in-laboratory polysomnography (PSG) and home-based sleep studies. The in-laboratory PSG is the gold standard for the diagnosis of OSA.4 The following physiologic signals are measured and interpreted during in-laboratory PSG: electroencephalogram, electro-oculogram, chin electromyogram, airflow, oxygen saturation, respiratory effort, and electrocardiogram.4
Because PSG is resource intensive, home-based sleep studies are an acceptable alternative; however, they should only be considered in patients with a high probability of moderate-to-severe OSA without comorbid sleep disorders or medical conditions. During home-based sleep studies, airflow, respiratory effort, and blood oxygenation are documented.10
The diagnosis of OSA is validated if the AHI on PSG or on home-based sleep studies is > 15 events/h or > 5 events/h with any of the following coexisting signs or symptoms: excessive daytime sleepiness; unintentional sleep episodes during wakefulness; unrefreshing sleep; fatigue; insomnia; waking up holding breath, gasping, or choking; or loud snoring, breathing interruptions, or both, described by the bed partner.10 In addition to diagnosing OSA, PSG and home-based sleep studies are useful in ruling out a variety of conditions that similarly cause excessive daytime sleepiness due to disrupted sleep.
The differential diagnosis of OSA includes, but is not limited to, periodic limb movement disorder, restless legs syndrome, narcolepsy, central sleep apnea, circadian rhythm sleep-wake disorders, respiratory diseases (ie, COPD, asthma), primary snoring, depression, and substance abuse.20
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