7A42.0

ICD-11 MMS 2026-01

Obesity hypoventilation syndrome

Description

Obesity hypoventilation syndrome is characterised by obesity (in adults, Body-Mass-Index > 30 kg/m²) and daytime hypercapnia indicated by arterial partial pressure of carbon dioxide (PaCO2) > 45 mm Hg that cannot be fully attributed to an underlying cardiopulmonary or neurologic disease. Hypercapnia worsens during sleep and is often associated with severe arterial oxygen desaturation. Obstructive sleep apnoea is also present in the majority of cases and should be diagnosed in addition to obesity hypoventilation. Note: A definitive diagnosis requires demonstration of daytime hypercapnia and objective evidence based on polysomnography, with carbon dioxide (CO2) monitoring (by arterial, end-tidal or transcutaneous measures).

Index terms

  • Obesity hypoventilation syndrome
  • OHS - [obesity hypoventilation syndrome]
  • Pickwick syndrome
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  • Pickwickian syndrome
  • alveolar hypoventilation syndrome
  • alveolus hypoventilation syndrome
  • cardiopulmonary obesity syndrome
  • Obesity hypoventilation syndrome with BMI 30.00-34.99 kg/m²
  • Obesity with alveolar hypoventilation with Body-Mass-Index of 30 but less than 35
  • Obesity with alveolar hypoventilation with Body-Mass-Index of 30 kg/m² but less than 35 kg/m²
  • Obesity hypoventilation syndrome with BMI 35.00-39.99 kg/m²
  • Obesity with alveolar hypoventilation with Body-Mass-Index of 35 but less than 40
  • Obesity with alveolar hypoventilation with Body-Mass-Index of 35 kg/m² but less than 40 kg/m²
  • Obesity hypoventilation syndrome with BMI greater than or equal to 40.00 kg/m²
  • Extreme obesity with alveolar hypoventilation with Body-Mass-Index of 40 and more
  • Extreme obesity with alveolar hypoventilation with Body-Mass-Index of 40 kg/m² and more
  • Extreme obesity with alveolar hypoventilation with BMI unspecified
  • Extreme obesity with alveolar hypoventilation with Body-Mass-Index unspecified

Inclusions

  • Pickwickian syndrome

Exclusions from above levels

  • KB2A – Apnoea of newborn

Sibling codes

  • 7A42.1 – Congenital central alveolar sleep-related hypoventilation
  • 7A42.2 – Non-congenital central hypoventilation with hypothalamic abnormalities
  • 7A42.3 – Idiopathic central alveolar hypoventilation
  • 7A42.4 – Sleep-related hypoventilation due to a medication or substance
  • 7A42.5 – Sleep-related hypoventilation due to medical condition
  • 7A42.6 – Sleep-related hypoxemia due to a medical condition
  • 7A42.Y – Other specified sleep-related hypoventilation or hypoxemia disorders
  • 7A42.Z – Sleep-related hypoventilation or hypoxemia disorders, unspecified

Foundation entity

Obesity hypoventilation syndrome – http://id.who.int/icd/entity/1514276050

Allowed postcoordination axes

Part of: 7A42: Sleep-related hypoventilation or hypoxemia disorders › 07: Sleep-wake disorders