Chapter 58 Physical Examination in Sleep Medicine

Abstract

The physical examination of the patient presenting with sleep concerns often provides important supporting information for the diagnosis of a sleep disorder. In this chapter, the examination findings characteristic of the major categories of sleep disorders are described and illustrated. These include findings observed in obstructive sleep apnea, central sleep apnea, hypoventilation syndromes, narcolepsy, restless legs syndrome, parasomnias, and bruxism.

After obtaining the medical history, the clinician performs the physical examination, a key and necessary element in evaluating patients with sleep disorders. The examination may provide important clues that lead to elucidation of the etiology and pathophysiology of the sleep disorder. This will guide the clinician in determining what diagnostic tests will be ordered, what comorbidities require management, and ultimately what therapy will be employed. The physical examination is a critical component monitoring outcome to treatment of some sleep disorders.

Sleep Apnea

Obstructive sleep apnea (OSA) is associated with multiple anatomic risk factors. The main ones are obesity, as reflected by elevated body mass index, and increased neck circumference. However, many patients with OSA are not obese but may exhibit reduced oropharyngeal airspace, retrognathia, or micrognathia. In contrast, central sleep apnea usually presents with abnormalities reflective of impaired respiratory effort, including the manifestations of heart failure, central nervous system (CNS) disease, or neuromuscular disease. Hypoventilation may be secondary to obesity but may also reflect pulmonary disease or neuromuscular and chest wall disorders. We review the manifestations of sleep apnea on the basis of anatomic site.

Sleep apnea often presents in association with obesity, which increases the prevalence 10-fold (20% to 40%).¹ Obesity and, in particular, the central type of obesity (Fig. 58-1) are significant risk factors for OSA.² They impose increased pharyngeal collapsibility through mechanical compression of the pharyngeal soft tissues and decreased lung volume through CNS-acting signaling proteins (adipokines) that may alter airway neuromuscular control.²^,³ OSA may independently predispose individuals to worsening obesity as a result of sleep deprivation, hypersomnia, and disrupted metabolism.⁴

Figure 58-1 Central obesity in OSA.

(From Kryger MH. Atlas of clinical sleep medicine. Philadelphia: Elsevier; 2010.)

Sleep apnea is also associated with endocrinopathies such as hypothyroidism ⁵^,⁶ and acromegaly.⁷ Hypothyroidism is a known cause of secondary OSA; oropharyngeal airway myopathy, edema, and obesity predispose patients to upper airway collapse and obstruction. Acromegaly results from excessive growth hormone, resulting in enlarged growth of the craniofacial bones, enlargement of the tongue (macroglossia), and thickening and enlargement of the laryngeal region; all of these factors can contribute to upper airway obstruction. Goiter, which is associated with acromegaly and hypothyroidism as well as a euthyroid state,⁸ can contribute to OSA (Fig. 58-2). Other conditions contributing to upper airway narrowing include Down syndrome and deposition disorders such as mucopolysaccharidosis and amyloidosis.

Figure 58-2 Goiter.

(From Kryger MH. Atlas of clinical sleep medicine. Philadelphia: Elsevier; 2010.)

Craniofacial Factors

Cephalometric measurements reveal that subjects with OSA have significant changes in the size and position of the soft palate and uvula, volume and position of the tongue, hyoid position, and mandibulomaxillary protrusion compared with controls. Mandibular retrognathia (Fig. 58-3) and micrognathia (Fig. 58-4), which cause the tongue to rest in a more superior and posterior position, impinging on the upper airway, can be detected on examination, especially by observing the patient from the side. A scalloped tongue (Fig. 58-5) may accompany micrognathia. Men with retrognathia or micrognathia may grow a beard to compensate for this anatomic variant. Crowded teeth (Fig. 58-6) and overjet (Fig. 58-7), with the mandibular teeth excessively posterior to the maxillary teeth, often accompany retrognathia or micrognathia. Racial differences in cephalometric properties probably play a major role in conferring risk for OSA in the absence of obesity. For example, in Chinese patients with OSA, a more retropositioned mandible was associated with more severe OSA, after controlling for obesity.⁹ In Japanese patients with OSA, micrognathia was a major risk factor.¹⁰ Children and adults with Down syndrome frequently have sleep apnea most likely related to a combination of craniofacial abnormality and macroglossia.