History and exam

Other diagnostic factors

common

male sex

In patients with obesity hypoventilation syndrome, there is a 2:1 male-to-female ratio.[23]

dyspnea

Seen in most causes of hypoventilation syndrome.[16][23][28] As the syndrome progresses, dyspnea on exertion followed by dyspnea at rest is the most common symptom encountered by patients with hypoventilation.

daytime sleepiness

Can be seen with most causes of hypoventilation syndrome.[16][23][28] Daytime hypersomnolence resulting from nocturnal hypoventilation may progress and be associated with symptoms of morning headaches and fatigue.

morning headache

Can be seen with most causes of hypoventilation syndrome.[16][23][28]

impaired cough

Seen in patients with neuromuscular disease.[16][28] Impaired cough in a disorder that causes respiratory muscle weakness may complicate the patient's course.

repeated lower respiratory tract infections

Seen in patients with neuromuscular disease.[16][28] If a disorder causes respiratory muscle weakness, repeated lower respiratory tract infections may complicate the patient's course.

BMI ≥30 kg/m²

Seen in patients with obesity hypoventilation syndrome, which has an increasing prevalence with increasing BMI.[23]

increased pulmonic component of second heart sound (P2)

Can be seen with most causes of hypoventilation syndrome.[16][23][28]

lower-extremity edema

Can be seen with most causes of hypoventilation syndrome.[16][23][28]

right-sided third heart sound (S3 gallop)

Can be seen with most causes of hypoventilation syndrome.[16][23][28]

left-sided fourth heart sound (S4 gallop)

Can be seen in patients with Cheyne-Stokes respiration due to congestive heart failure.

Risk factors

strong

body mass index (BMI) ≥30 kg/m²

The prevalence of obesity hypoventilation syndrome in patients with obstructive sleep apnea significantly increases with increasing BMI.[23]

restrictive thoracic disorders

Patients with chest wall deformities (kyphoscoliosis, fibrothorax, or thorocoplasty) and neuromuscular disorders, particularly Duchenne muscular dystrophy and other types of muscular dystrophies and spinal muscular atrophies, are at risk of hypoventilation.

central nervous system disorders

Disorders include central sleep apnea syndromes, such as idiopathic central sleep apnea, and Cheyne-Stokes respiration. Another central but rare disorder is congenital central alveolar hypoventilation.[24]

obstructive airway disease

Obstructive airway disease (in particular, COPD) can develop alveolar hypoventilation.

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