Platypnea-Orthodeoxia Syndrome

OVERVIEW

  • Platypnea-orthodeoxia (P-O) syndrome is an under-diagnosed condition characterized by dyspnea and deoxygenation when changing from a recumbent to an upright position
  • It is usually caused by increased right-to-left shunting of blood on assuming an upright position, with normal pressure in the right atrium
  • It may also be caused by intrapulmonary shunting combined with extensive pulmonary lesions or severe V/Q mismatching

CAUSES

Common

  • ASD or PFO with position-dependent shunting, often in combination with one of the conditions below.

Rare

  • Other Cardiac
    — Pericardial effusion
    — Constrictive pericarditis
    — Aortic aneurysm
  • Pulmonary
    — Multiple pulmonary emboli
    — Pulmonary emphysema
    — Radiation-induced bronchial stenosis
    — Hepatopulmonary syndrome
    — Amiodarone toxicity of the lungs
    — Pulmonary A-V communications
    — PCP pnuemonia
    — fat embolism syndrome
  • Autonomic
    — Parkinson disease
    — Bilateral thoracic sympathectomy
  • Abdominal
    — Hepatic cirrhosis
    — Ileus

INVESTIGATIONS

  • supine and upright PaO2 measurement
  • tilt transesophageal echocardiogram with bubble study (<100% sensitive) – diagnosis of the shunt can be difficult
  • look for other underlying causes

MANAGEMENT

  • Closure of the ASD or PFO
  • Treat any associated condition
    — A case associated with Parkinson’s disease was attributed to postural hypotension, and improved with fludrocortisone.
    — A case associated with radiation-induced bronchial stenosis was relieved by bronchial dilation initially, and later by bronchial stenting.
    — A case associated with bilateral thoracic sympathectomy (van Heerdon 2004) was treated initially with noradrenaline and almitrine.
Advertisements

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s