Inspection of the Face

In some patients, inspection of the face can reveal the disease—for example, thyroid disease (see Chapter 15.1) or acromegaly (see Chapter 15.2)—that may be causing sleep apnea. Inspection can also give insight into physiologic abnormalities.

Hyperpigmentation on the forehead, resembling acanthosis nigricans, may be present in the patient with sleep apnea (child or adult) who sleeps sitting up with the forehead resting on a forearm resting on a table (see Fig. 13.1-3, B). This is often found in patients with very severe apnea because it is the only position they can sleep in.

In many instances sleep apnea is apparent at the first meeting with the patient. For example, drooping eyelids suggest sleepiness (Figs. 13.1-4 and 13.1-5, A). Floppy eyelids have also been associated with sleep apnea (see Fig. 13.5, B). Arched eyebrows can be a sign that the patient is trying to open her eyelids.

The patient shown in Figure 13.1-6 is obese, cyanotic, and has bloodshot eyes. The latter finding was related to polycythemia. Obesity hypoventilation syndrome or overlap syndrome should be suspected when a patient has these findings.

All patients with Down syndrome should be suspected of having sleep apnea (Fig. 13.1-7).

Bony Structures

Abnormalities in the skeletal structures of the face can lead to an abnormal position of the adjacent structures or attached soft tissues. Such abnormalities can obstruct the nasal or pharyngeal airways (Figs. 13.1-8 and 13.1-9).

Diseases of the Nose and Nares

The patient shown in Figure 13.1-22 has severe rosacea. This disease can lead to nasal obstruction and sleep apnea. Diseases that affect the nasal turbinates, such as allergic rhinitis, can also lead to nasal obstruction (Fig. 13.1-23). Other abnormalities that may be found include a deviated nasal septum, which in some patients can be associated with a high-arched palate.

Mallampati Classification

The Mallampati classification describes the relationship between the tongue and the size of the pharynx and was first described as a method for anesthesiologists to predict difficult tracheal intubation. The patient, in the sitting position, is asked to open his or her mouth as far as possible and to protrude the tongue. The Mallampati classification is as follows:

Examination of the Tonsils

Enlarged tonsils and adenoids can lead to sleep apnea by obstructing the upper airway during sleep. Adenoids cannot be visualized in a routine physical examination. Enlarged tonsils and adenoids are the most common cause of sleep apnea in the pediatric population. Examination of the tonsils may or may not require use of a tongue blade.

Tonsil size is graded on a scale from 0 (no tonsils) to 4 (“kissing tonsils” that touch at midline):

Variants and Abnormal Airway Pharyngeal Findings

In Figure 13.1-35, D, the right tonsil is much larger than the left and extends beyond the midline. It was initially difficult to visualize because it extended behind the uvula. This would be classified as equivalent to grade 4 enlarged tonsils.

In Figure 13.1-36, a nubbin of left tonsillar tissue can be seen. This patient frequently awakened with a sore throat, and the pharyngeal tissues show evidence of trauma (redness) as a result of snoring.

Figure 13.1-37 shows an unexpected finding in a sleep apnea patient: a tiny neoplastic lesion just to the right of the uvula. The most common surgical procedure involving the upper airway is uvulopalatopharyngoplasty, which usually involves removal of the uvula and variable amounts of the soft palate (depending on the surgeon), tonsils, adenoids, and redundant tissue in the pharynx. In the cases shown in Figures 13.1-38 and 13.1-39, uvulopalatopharyngoplasty was unsuccessful in treating the apnea. Note the differences in anatomic outcome in these examples.

Peripheral Edema

In very obese patients who spend most of their time in bed, edema might not always be maximal in the ankles and feet (Fig. 13.1-44). When edema is very severe in a patient with a sleep breathing disorder, it is almost always in the context of a hypoventilation syndrome (Fig. 13.1-45). Chronic edema results in discoloration and may result in infections that are difficult to treat (Figs. 13.1-46 and 13.1-47).

Symptoms

Symptoms have generally been present for years before the diagnosis is made. The cardinal symptoms of OSA appear in Box 13.2-3 and in Chapter 8. An interview of the patient or the patient’s bed partner or parent (see Chapter 13.3) will shed light on the symptoms and how they affect the patient’s life.

Examination

The physical examination of the patient with SDB is covered in detail in Chapter 13.1. In OSA, the primary findings in adults are obesity, a crowded posterior airway, hypertension (especially difficult-to-control hypertension), and other abnormalities that may narrow the airway, such as retrognathia, an enlarged tongue, or a “birdlike face,” as seen in Treacher Collins syndrome.

Laboratory Evaluation

The comprehensive overnight polysomnogram is currently the most widely used diagnostic test to document sleep apnea. Home sleep testing is being increasingly used for diagnosis in patients with a high pretest probability of having sleep apnea (see Chapter 18).

Data Obtained in a Sleep Study

The current American Academy of Sleep Medicine (AASM) scoring manual specifies the use of an oronasal thermal sensor to assess airflow for apnea and a nasal pressure transducer to assess airflow for hypopnea. Information from a nasal pressure transducer may be misleading in a mouth breather, and the signal from a temperature sensor is not linear. Measuring end-tidal CO₂ adds an additional dimension of helpful information. The reader is encouraged not to slavishly follow the manual at all times but rather to examine all the available data to assess and understand the physiologic abnormalities. Synchronized digital video is often invaluable in assessing the patient (see Chapter 21).

Scoring of Respiratory Events

In adults (those aged 18 years or older), both apneas and hypopneas must last at least 10 seconds. Apnea occurs when oronasal airflow is reduced by 90% or more from baseline, and hypopnea occurs when the nasal pressure transducer signal is reduced by 30% or more from baseline with a 3% or greater drop in arterial oxygen saturation (SaO₂). An alternative rule for hypopnea requires a 50% or more reduction in nasal pressure transducer signal with a 4% or greater drop in SaO₂ associated with an arousal. If respiratory effort is present during the event, the hypopnea is classified as obstructive; if effort is absent, it is classified as central. Figure 13.2-1 demonstrates a respiratory event that meets criteria for a hypopnea, with a marked reduction in the pressure transducer signal, but not the airflow or thermal sensor signal, and a drop in SaO₂ from 90% to 86%. In children younger than 13 years, the length of the event changes from 10 seconds to two missed breaths as determined by the baseline respiratory rate (see Chapter 13.3). The scoring rules are flexible for ages 13 to 18 years and allow scoring either by adult or pediatric criteria. Figure 13.2-2 demonstrates a hypopnea in which the SaO₂ has fallen to 90%. In Figure 13.2-3, the somewhat arbitrary nature of these definitions, as well as the difference in thermal and pressure signals, is demonstrated. The term respiratory effort–related arousal was coined to capture respiratory events that do not qualify as apneas or hypopneas (Fig. 13.2-4). However, although the 2012 scoring manual calls for either respiratory inductance plethysmography or polyvinylidene fluoride film signal or an esophageal pressure manometer to assess respiratory effort, the latter device is almost never used in routine clinical practice.