2. Platypnoea Orthodeoxia Syndrome (POS)
Platypnoea refers to worsening of dyspnoea on assuming
an
upright posture from supine.
Orthodeoxia refers to worsening of arterial PaO2 on
upright
postures.
First described by Butchell et al in 1949
Total cases reported - 188Kubler P, Gibbs H, Garrabhy P; Heart 2000
3. Etiology
PFO and other interatrial defects
Pericardial effusion
Constrictive pericarditis
Emphysema
Amiodarone induced pulmonary fibrosis,
Pulmonary embolism
Post pneumonectomy
Hepatopulmonary syndrome
Stroke
Seward JB et al. Platypnea orthodeoxia: clinical profile, diagnostic workup, manage
and report of 7 cases. Mayo Clin Proc 1984;59:221–31
4. Clinical features
Dyspnoea with or without cyanosis in the upright posture
which relieves on recumbent posture.
May be associated with diaphoresis, tachypnoea and
tachycardia.
Initial assessment of the patients should be done with
pulse oximetry and ABG analysis in both supine and
upright posture.
Rodriguez, Roisin R, Agusti AG, Roca J et al, Thorax. 1992 Nov;
5. Pathophysiology
Two components are required for the development of
POS.
An interatrial communication like PFO, ASD or atrial
septal aneurism with septal fenestration or
intrapulmonary shunting as in hepatopulmonary
syndrome.
Second a functional component that promotes abnormal
shunting when the patient rises from recumbent to
upright position like deformity in the atrial septum or in
the right atrial anatomy that increases the streaming of
blood from the inferior venacava through the defect.
Robin ED et al: Platypnea related to orthodeoxia caused by true vascular lung shun
N Engl J Med 294:941-943, 1976
6. Diagnosis
Definitive diagnosis can be made by Echocardiography
with
doppler mode and contrast echocardiography -
transthoracic
and transoesophageal with postural manoeuvres.
Intrapulmonary shunts can be identified by contrast
enhanced
echocardiography, perfusion scan(scintigraphy) with
macroaggregated albumin and pulmonary arteriography.
Cheng et al, Platypnea-orthodeoxia syndrome: etiology, differential
diagnosis, and
7. Treatment
Treatment depends on the cause.
Percutaneous or surgical closure of the defect is the
curative therapy for intracardiac shunts.Associated
anatomical defects may require surgical correction.
Underlying pulmonary diseases should be treated.
In patients with hepatopulmonary syndrome, liver
transplantation is the only curative treatment.
Akin et al, The platypnea-orthodeoxia syndrome. European Review for
Medical and