Obesity Hyperventilation Syndrome

Exam Cram

• Chronic hypoventilation (hypercapnia) from obesity

• Raised bicarbonate to compensate for chronic hypercapnia

• Restrictive lung disease on spirometry, increased TLCO

Outline

Obesity causes a restrictive lung disease pattern from the increase intrathoracic pressures preventing the lung from fully expanding. This results in poor ventilation and inability to clear C02. Hence CO2 retention and compensatory raised bicarbonate. 

History

• Snoring

• Night time urinary incontinence

• Increased day time tiredness

Ix

• Raised bicarb

• CO2 retention

• Spirometry: restrictive pattern

Differentials

• COPD

• OSA

Management

1. Weight loss, 

   1. 1. • For lifestyle, medical, surgical interventions, see Obesity 

2. CPAP

Written 2024