Platypnea

Platypnea or platypnoea is shortness of breath (dyspnea) that is relieved when lying down, and worsens when sitting or standing upright. It is the opposite of orthopnea.^[1] The condition was first described in 1949 and named in 1969.^[2]

A related condition, orthodeoxia, describes the clinical finding of low oxygen saturation in the upright position, which improves when lying down.^[3]

Platypnea and orthodeoxia (low oxygen levels when in upright posture) can co-exist, and this combination is named platypnea-orthodeoxia syndrome.^[4][5] The syndrome is considered extremely rare however.^[4]

Causes

Platypnea is usually due to either hepatopulmonary syndrome or an anatomical cardiovascular defect increasing positional right-to-left shunting (bloodflow from the right to the left part of the circulatory system) such as a patent foramen ovale. These defects include rare syndromes in which the venous blood from the liver does not pass through the lungs sufficiently, or if venous blood from the portal circulation reaches the inferior vena cava without passing through the liver sufficiently (Abernethy malformation, type 1).^{[citation needed]}

Etymology and pronunciation

The word platypnea uses combining forms of platy- + -pnea, from Greek platus (= flat) and pnoia (=breath). See pronunciation information at dyspnea.

See also

• Paroxysmal nocturnal dyspnoea
• Orthopnea
• Trepopnea
• Bendopnea

References

1. Dorland's Illustrated Medical Dictionary (32 ed.). Elsevier Saunders. 2012. p. 1459. ISBN 978-0-8089-2418-0.
2. Robin ED, McCauley RF (1997). "An analysis of platypnea-orthodeoxia syndrome including a 'new' therapeutic approach". Chest. 112 (6): 1449–51. doi:10.1378/chest.112.6.1449. PMID 9404736.
3. Dorland's Illustrated Medical Dictionary (32 ed.). Elsevier Saunders. 2012. p. 1337. ISBN 978-0-8089-2418-0.
4. Cheng TO (2002). "Mechanisms of platypnea-orthodeoxia: what causes water to flow uphill?". Circulation. 105 (6): e47. doi:10.1161/circ.105.6.e47. hdl:10553/76643. PMID 11839642.
5. Kubler P, Gibbs H, Garrahy P (2000). "Platypnoea-orthodeoxia syndrome". Heart. 83 (2): 221–3. doi:10.1136/heart.83.2.221. PMC 1729301. PMID 10648502.