Physical Examination Findings in Obstructive Sleep Apnea
The physical examination of a patient with suspected obstructive sleep apnea must systematically evaluate the upper airway from nose to larynx, focusing on anatomic obstruction sites, with particular attention to neck circumference (>17 inches in men, >16 inches in women), craniofacial abnormalities, and pharyngeal crowding. 1
Upper Airway Assessment
Nasal and Pharyngeal Examination:
- Evaluate the nasal passages for anatomic obstruction including septal deviation, turbinate hypertrophy, or polyps 1
- Assess the pharyngeal airway for soft tissue crowding and narrowing, as the velopharyngeal/retropalatal segment is the predominant site of collapse 2
- Document tonsil size, specifically noting if tonsils are nearly touching or touching in the midline, which is highly predictive of OSA 1
- Measure tongue volume and assess for macroglossia or posterior displacement 1
Craniofacial and Skeletal Structure
Mandibular and Maxillary Assessment:
- Examine for retrognathia (posterior positioning of the mandible) or micrognathia (small mandible), which can cause OSA independent of obesity 1
- Assess craniofacial abnormalities affecting the airway, as these alter the mechanical loads on the upper airway 1, 3
- Evaluate dental structures if mandibular advancement devices are being considered for treatment 1
Anthropometric Measurements
Critical Measurements:
- Neck circumference is essential: >17 inches in men or >16 inches in women is a key predictor, particularly in males 1
- Document body mass index (BMI), with BMI ≥35 kg/m² representing the 95th percentile threshold associated with OSA 1
- Assess for truncal and neck obesity patterns 1
Cardiovascular and Systemic Findings
Associated Physical Findings:
- Measure blood pressure, as OSA should be suspected in all hypertensive patients, especially those with treatment-resistant hypertension 1
- Look for signs of cardiovascular disease, heart failure, or previous stroke 1
- Screen for signs of hypothyroidism or acromegaly, which are associated conditions 1
Common Pitfalls to Avoid
Do not limit examination to the oropharynx alone - the entire upper airway from nose to larynx requires systematic evaluation, as obstruction can occur at multiple levels 4
Do not assume obesity is always present - craniofacial abnormalities can cause significant OSA in non-obese patients, making skeletal assessment mandatory 1
Do not overlook neck circumference measurement - this simple measurement is one of the most predictive physical examination findings and should never be omitted 1
Integration with Clinical Decision-Making
The physical examination findings should be combined with history (snoring, witnessed apneas, daytime sleepiness) to determine whether to proceed with polysomnography or manage based on clinical criteria alone 1. When examination reveals severe abnormalities (markedly increased neck circumference, severe tonsillar hypertrophy, significant craniofacial abnormalities), the patient should be treated as having severe sleep apnea even without formal sleep study 1.