Importance of Platypnea Orthodeoxia in the Differential Diagnosis of Dyspnea

□ EDITORIAL □

Bonpei Takase 1, Yoshihiro Tanaka 2, Hidemi Hattori 2 and Masayuki Ishihara 2

Key words: postural change, hypoxia, pulmonary circulation

(Intern Med 51: 1651-1652, 2012) (DOI: 10.2169/internalmedicine.51.7720)

Platypea orthodeoxia is a relatively uncommon symptom lapse of the inferior part of the lung vessels, which subse- that is not frequently observed in daily clinical practice. quently increases either ventilation perfusion mismatch or Platypnea is dyspnea on moving from the supine to the up- intrapulmonary shunt (5). As described earlier, these condi- right position. In addition, orthodeoxia is arterial deoxygena- tions markedly aggravate hypoxia. tion when moving from the supine to upright position. Thus, In addition to the effect of hydrothorax, vasodilatation at platypnea orthodeoxia is typically an overt symptom when the level of the pulmonary circulation occurs in the hepato- the patient’s posture changes from the supine to the upright pulmonary syndrome, which is the typical characteristic of position. This symptom is observed in patients with hepato- hepatopulmonary syndrome. This condition leads to arterial pulmonary syndrome, which is most frequently and typically hypoxemia manifested as platypnea orthodeoxia. Since the caused by liver cirrhosis (1-3). normal diameter of pulmonary capillaries is approximately 8 On the other hand, orthopnea is similar to platypnea μm, red blood cells can pass through them one at a time, orthodeoxia but its features are the reverse of platypnea which facilitates effective oxygenation of red blood cells. In orthodeoxia. Orthopnea is well known and one of the most the hepatopulmonary syndrome, the pulmonary capillaries common physical findings in patients with congestive heart are reported to be dilated to approximately 500 μm (5, 6), failure. In orthopnea, hypoxia improves with the postural so that many red blood cells pass through the pulmonary change from supine to sitting and/or standing. In general, capillaries without oxygenation. This is equivalent to a right- orthostatic malfunction of not only the respiratory condition to-left shunt in the pulmonary circulation, causing signifi- but also consciousness is typically observed in patients with cant hypoxia. This explains the proposed mechanism of orthostatic hypotension or neurally mediated syncope (ex- platypnea orthodeoxia in the hepatopulmonary syndrome. pressed as orthostatic intolerance syndrome). These symp- Patients with hepatopulmanary syndrome generally prefer toms should be considered in the differential diagnosis of the supine position to the upright one. platypnea orthodeoxia. In this issue of Internal Medicine, Ohfuji et al. (7) report According to previous reports (1, 4, 5), the factors in the an interesting case of unrevealed atrial septal defect with lung that cause hypoxia are as follows: 1) hypoventilation, platypnea orthodeoxia. In their patient, postural change in- 2) diffusion impairment, 3) intrapulmonary or extrapulmon- duced an increased right atrial pressure, which increased the ary shunt, and 4) ventilation perfusion mismatch. In the he- right-to-left shunt and subsequently aggravated the intrapul- patopulmonary syndrome that manifests with platypnea monary shunt. This is the same mechanism of upright orthodeoxia, marked ascites and hydrothorax with pleural ef- posture-induced hypoxia as that seen in the hepatopulmon- fusion are common. Especially when a significant pleural ef- ary syndrome. In contrast to relatively common orthostatic fusion (hydrothorax) is present, the intrathoracic effusion hypotension and/or neurally mediated syncope, platypnea spreads diffusely over the posterior space of the thorax in orthodeoxia is usually reported in hepatopulmonary syn- the supine position. This condition prevents significant col- drome as described above. As Ohfuji et al. pointed out, lapse of the lung. However, postural changes from the su- platypnea orthodeoxia is also observed under conditions in pine to the upright position cause the pleural effusion to ac- which postural changes from supine to sitting and/or stand- cumulate in the lower part of the lung. This can induce col- ing increase the right-to-left shunt in several disorders, such

１Department of Intensive Care Medicine, National Defense Medical College, Japan and ２Division of Biomedical Engineering, National Defense Medical College Research Institute, Japan Received for publication March 12, 2012; Accepted for publication March 15, 2012 Correspondence to Dr. Bonpei Takase, [email protected]

1651 Intern Med 51: 1651-1652, 2012 DOI: 10.2169/internalmedicine.51.7720 as patent foramen ovale/atrial septal defect, hypothyroidism- management. South Med J 104: 215-221, 2011. induced pericardial effusion, or pulmonary hypertension in 5. Agrawal G, Kumar N, Rosha D. Hepatopulmonary syndrome. J Assoc Physicians India 56: 265-267, 2008. obstructive sleep apnea syndrome (8-14). 6. Garcia-Tsao G. Cirrhosis and its sequelae. In: Cecil Medicine. 23 Platypnea orthodeoxia is a relatively rare symptom com- rd edition. Goldman L, Ausiello D, Eds. Saunders, Elsevier, Phila- pared to orthopnea. However, platypnea orthodeoxia should delphia, 2008: 1140-1147. be considered in the differential diagnosis when patients 7. Ohfuji T, Obase Y, Ikeda M, et al. A case of platypnea orthode- with a chief complaint of either dyspnea or orthostatic hy- oxia syndrome: a persistent history taking was the key to the diag- potension and/or neurally mediated syncope (orthostatic in- nose. Intern Med 51: 1701-1704, 2012. 8. Robin ED, Laman D, Horn BR, Theodore J. Platypnea related to tolerance) are seen in routine clinical practice. In this re- orthodeoxia caused by true vascular lung shunts. N Engl J Med spect, the report of Ohfuji et al. in this issue is very impor- 294: 941-943, 1976. tant and provides useful information. 9. Seward JB, Hayes DL, Smith HC, et al. Platypnea-orthodeoxia: clinical profile, diagnostic workup, management, and report of The authors state that they have no Conflict of Interest (COI). seven cases. Mayo Clin Proc 59: 221-231, 1984. 10. Robin ED, McCauley RF. An analysis of platypnea-orthodeoxia syndrome including a “new” therapeutic approach. Chest 112: References 1449-1451, 1997. 11. Baptista R, da Silva AM, Castro G, Monteiro P, Providência LA. 1. Cheng TO. Platypnea-orthodeoxia syndrome: etiology, differential Ascending aortic aneurysm and patent foramen ovale: a rare cause diagnosis, and management. Catheter Cardiovasc Interv 47: 64-66, of platypnea-orthodeoxia. Rev Port Cardiol 30: 445-450, 2011. 1999. 12. Teupe CH, Groenefeld GC. Platypnea-orthodeoxia due to osteopo- 2. Cheng TO. Mechanisms of platypnea-orthodeoxia: what causes rosis and severe kyphosis: a rare cause for dyspnea and hypoxe- water to flow uphill? Circulation 105: e47, 2002. mia. Heart Int 6: e13, 2011. 3. Edwards AL, Cornatzer E, Shelton RW. Platypnea-Orthodeoxia 13. Odell JA, Keller CA, Erasmus DB, Stritt MT. Traumatic bronchial syndrome: what is the driving force? Am J Med Sci 2011 Jun 16. rupture and platypnea-orthodeoxia. Ann Thorac Surg 93: 662-664, [Epub ahead of print]. 2012. 4. Brunner M, Tapson V. Platypnea-orthodeoxia: bilateral lower-lobe 14. Gourgiotis S, Aloizos S, Gakis C, Salemis NS. Platypnea- pulmonary emboli and review of associated pathophysiology and orthodeoxia due to fat embolism. Int J Surg Case Rep 2: 147-149, 2011.

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