TITLE OF CASE
AUTHORS OF CASE Please indicate corresponding author by *(after the author’s name)
SUMMARY Up to 150 words summarising the case presentation and outcome
Central cyanosis can occur due to shunt (intra or extracardiac right to left shunt), polycythemia, respiratory disease or drugs.(1) Intracardiac shunts are usually complex structural heart diseases causing mixing of oxygenated and deoxygenated blood or causing the deoxygenated blood from the systemic venous return to bypass the pulmonary vascular bed before supplying the systemic circulation. Extracardiac shunts include systemic to systemic shunts like right or left SVC draining into the left atrium and pulmonary to pulmonary shunts like pulmonary arteriovenous malformations. (2) We present a very rare case of central cyanosis in a young male due to a PA to LA fistula.
BACKGROUND Why you think this case is important – why you decided to write it up
PA to LA fistula is a very rare cause of central cyanosis in a structurally normal heart. Work up of central cyanosis should include an active search for this pathology as it has important disease associations and future complications which need to be identified and treated early. In light of treatable nature and absence of major associated structural heart disease, long term prognosis of this disease is good if identified and treated early.
CASE PRESENTATION Presenting features, medical/social/family history
A 17-year-old boy presented with decreased exercise tolerance and mild cyanosis. He had no history of hemoptysis, squatting phenomenon, seizures, fever, night sweats, weight loss, or chest pain. Moreover, family history was not significant for cardiac problems or hypertension. His physical growth was adequate. There were no haemangiomas. Precordial examination was normal and systemic examination revealed central cyanosis. There were no murmurs.
INVESTIGATIONS If relevant
Resting oxygen saturation was. X-ray chest showed a crescentic shadow parallel to the right atrium Haemoglobin was g/dl. ECG showed. Rest of all laboratory findings were within normal limits. Contrast echocardiogram showed bubble contrast in the left chambers, raising suspicion of arteriovenous (AV) shunting. No other intracardiac anomalies were detected. Computed tomography pulmonary angiogram with 3-dimensional reconstruction showed a large fistula communicating right lower lobe pulmonary artery (PA) to left atrium (LA).
DIFFERENTIAL DIAGNOSIS If relevant
TREATMENT If relevant
OUTCOME AND FOLLOW-UP
DISCUSSION including very brief review of similar published cases (how many similar cases have been published?)
Pulmonary arteriovenous fistula refers to an abnormal communication between a pulmonary artery and vein with absence of the capillary bed that links always the two 3. Embryologically, it develops due to incomplete degeneration of the septum between the arterial and venous plexus of the pulmonary vascular bed. It may also be due to formation of thin walled sacs secondary to a defect in the capillary loops. A pulmonary vein connected to such a fistula is absorbed into LA during development, forming a PA–LA fistula 4.
PA to LA fistulas were first described by Friedlich et al. in 1950 (5). Right PA to LA fistula is commoner, while only very few cases of left PA to LA fistula have been reported (6,7,8). They are classified into four types by De Souza e Silva and Ohara et al (9,10). In the most common type I there is and an anomalous connection between the posterior aspect of the proximal RPA and LA. Type II shows a supernumerary pulmonary branch of the PA with associated absence of the right inferior pulmonary vein. In Type III there is abnormal pulmonary venous return of all pulmonary veins to an aneurysmal connection between the LA and RPA. In type IV, the right pulmonary veins return to a fistulous tract between the RPA and LA, while the left pulmonary veins return normally to the LA.
These can manifest from day 1 to middle age 4, although most commonly in the third decade. 11. In newborns, large shunts can cause severe heart failure. The most common signs and symptoms are dyspnea, seen in 50%, neurological symptoms seen in 20% 12, telangiectasias in 33% 13, and cyanosis in 60% patients. Other presentations can be hemoptysis or polycythemia. Cyanosis is usually not evident until adolescence or adulthood.
The natural history of this lesion is characterized by the development of pulmonary hypertension and risk of chronic cyanosis due to the left to right shunt. Untreated, it may lead to pulmonary edema with pulmonary hypertension, infective endocarditis, systemic embolization, cerebral abscesses, and aneurysmal growth with the risk of rupture which can be fatal. In light of these complications, surgical correction is recommended soon after diagnosis.
Atrial septal defect is a common association. Other associations include PDA, LPA stenosis, absent lower or middle lobe, sequestration and bronchial diverticulum (14). We did not notice any such abnormality in our patient. Potential complications such as chronic hypoxemia, infective embolism or cerebrovascular accident may ensue if left untreated.
Cyanosis, little or no abnormal precordial and systemic findings, and a cresentric shadow parallel to heart border on x-ray should raise suspicion to the diagnosis. The diagnosis should be suspected in a patient with cyanosis and a structurally normal heart. Echocardiography confirms a PA-to-pulmonary venous or LA fistula. The finding is early appearance of dense contrast in the LA (within 2-3 cardiac cycles) after contrast injection into arm veins. Cardiac catheterization shows LA desaturation not responding to inhaled oxygen. A selective pulmonary angiogram reveals the communication.
Treatment modalities include ligation or division of the anomalous vessel, transcatheter closure by using a device or coils or a transcatheter trans-septal approach using a duct occlude. (15,16) Routine imaging is sufficient for follow up.
LEARNING POINTS/TAKE HOME MESSAGES 3 to 5 bullet points
· PA-LA fistula, although rare, is an important and correctable cause of central cyanosis.
· Role of multislice computed tomography in delineating the complex vascular anatomy with great accuracy, replacing the need of more invasive diagnostic procedure.
REFERENCES Vancouver style (Was the patient involved in a clinical trial? Please reference related articles)
1The American Journal of Medicine, Vol 126, No 3, March 2013
4 Ohara H, Ito K, Kohguche N, Okhawa Y, Akasak T, Takarada M, Aoki H, Ogata M, Nishibatake M, Fukatsu M, Matsushima K, Sasaki Y. Direct communications between the right pulmonary artery and left atrium. J Thorac Cardiovasc Surg 1979;77:742–747.
5 A. Friedlich, R.J. Bing, S.G. Blount JrPhysiological studies in congenital heart disease. IX. Circulatory dynamics in the anomalies of venous return to the heart including pulmonary arteriovenous fistula
Bull Johns Hopkins Hosp, 86 (1950), pp. 20-57
6 Chowdhury UK, Kothari SS, Airan B, Subramaniam KG, Venugopal P. Right pulmonary artery to left atrium communication. Ann Thorac Surg. 2005;80(1):365-370.
7 Karnik AM1, Nilsson U, Vijayaraghavan G, Hashmi J, Shuhaiber H. Direct communication between left pulmonary artery and the left atrium. Chest. 1989;96(4):937-939.
8 Sambasivam KA, Dhanawade SM, Krishnaswami S. Direct communication between left pulmonary artery and left atrium. Ind Heart J. 1995;47:40-41.
9 N.A. De Souza e Silva, E.R. Giuliani, D.G. Ritter, G.D. Davis, J.R. PluthCommunication between right pulmonary artery and left atrium
Am J Cardiol, 34 (1974), pp. 857-863
10 H. Ohara, K. Ito, N. Kohguchi, Y. Ohkawa, T. Akasaka, M. Takarada, et al.Direct communication between the right pulmonary artery and the left atrium: a case report and review of literature
J Thorac Cardiovasc Surg, 77 (1979), pp. 742-747
11 Sambasivam K, Dhanawade SM, Krishnaswami S. Direct communication between left pulmonary artery and left atrium. Indian Heart J 1995;47:40–41.
12 Verel D, Grainger RG, Taylor DG. Direct communication of pulmonary artery with the left atrium. Br Heart J 1964;26:856–858
13 Moyner JH, Glandz G, Brest AN. Pulmonary AV fistula, physiological and clinical considerations. Am J Med 1962;32:417–435.
14 Kroeker EJ, Admas HD, Leon AS, Pouget JM. Congenital communication between a pulmonary artery and the left atrium. Physiological observations and review of the literature. Am J Med 1963;34:721-5
15 Zeebregts CJ, Nijveld A, Lam J, van Oort AM, Lacquet LK. Surgical treatment of fistula between right pulmonary artery and left atrium: Presentation of two cases and review of literature. Eur J Cardiothorac Surg. 1997;11:1056–6
16 Krishnamoorthy KM, Rao S. Pulmonary artery to left atrial fistula. Eur J Cardiothorac Surg. 2001;20:1052–3
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