History

Fact Explanation
Asymptomatic Most patients with small (less than 2cm in diameter) pulmonary arteriovenous fistulae are asymptomatic. [1,5,7]
Epistaxis Epistaxis is the commonest presenting complaint. Patients present with recurrent episodes of epistaxis either spontaneous or secondary to minor trauma. [1,7]
Dyspnea Dyspnea, the second commonest presenting complain occurs due to right to left shunt of blood. Patients complain of dyspnea on exertion which might progress in to dyspnea on standing upwards (platypnea) as well. [1,5,7]
Haemoptysis [1] A common complain at presentation, but massive hemoptysis is rarely seen.
Stroke and transient ischemic attacks Patients can develop stroke or recurrent transient ischemic attacks due to increased risk of venous embolization from the pulmonary fistulae. Patients present with dysarthria, facial asymmetry and hemiparesis. [1,4]
Symptoms of brain abscess [1] Patients present with prolonged fever, headache, nausea, vomiting and focal neurological signs.
Syncope [7] A less common presentation and it is due to hypoxemia.
Migraine Although the specific cause is uncertain migraine is known to occur with pulmonary arteriovenous malformations. [5,6]
Congenital Most of the (80%) pulmonary arteriovenous fistula are congenital and very rarely it can be acquired secondary to chest trauma, thoracic surgery, hepatic cirrhosis, metastatic carcinoma, mitral stenosis, infections (actinomycosis, schistosomiasis), Fanconi's syndrome and systemic amyloidosis. [1,3,7]
Visual disturbances [7] Due to paradoxical embolization from the pulmonary arteriovenous fistula.
Symptoms of congestive cardiac failure [7] Patients develop congestive cardiac failure due to large fistula and subsequent left heart overload.
References
  1. KHURSHID I. Pulmonary arteriovenous malformation. [online] 2002 April, 78(918):191-197 [viewed 05 July 2014] Available from: doi:10.1136/pmj.78.918.191
  2. LIN ANGELA E, BASSON CRAIG T, GOLDMUNTZ ELIZABETH, MAGOULAS PILAR L, MCDERMOTT DEBORAH A, et al. Adults with genetic syndromes and cardiovascular abnormalities: clinical history and management. Genet Med [online] 2008 July, 10(7):469-494 [viewed 02 July 2014] Available from: doi:10.1097/GIM.0b013e3181772111
  3. LE ROUX B. T., GIBB B. H., WAINWRIGHT J.. Pulmonary arteriovenous fistula with bilharzial pulmonary hypertension. Heart [online] 1970 July, 32(4):571-574 [viewed 05 July 2014] Available from: doi:10.1136/hrt.32.4.571
  4. BRIAN C. A., PAYNE R. M., LINK K. M., HUNDLEY W. G., WARNER J. G.. Pulmonary Arteriovenous Malformation. Circulation [online] 1999 July, 100(4):e29-e30 [viewed 06 July 2014] Available from: doi:10.1161/01.CIR.100.4.e29
  5. HE M, YU S, WANG G. One case of sporadic hemiplegic migraine with multiple pulmonary arteriovenous malformation J Headache Pain [online] 2011 Jun, 12(3):369-371 [viewed 06 July 2014] Available from: doi:10.1007/s10194-011-0292-x
  6. ASOH KENTARO, SAKURAI KENZO, MIZUNO MASANORI, TSUZUKI YOSHIMITSU, ARIMA MASAKI, GOTO KENJIRO, MURANO KOHTARO. Improvement of migraine symptoms after coil embolotherapy of pulmonary arteriovenous fistulae. [online] 2009 September, 52(3):e175-e177 [viewed 06 July 2014] Available from: doi:10.1111/j.1442-200X.2010.03111.x
  7. GOSSAGE JAMES R., KANJ GHASSAN. Pulmonary Arteriovenous Malformations. Am J Respir Crit Care Med [online] 1998 August, 158(2):643-661 [viewed 06 July 2014] Available from: doi:10.1164/ajrccm.158.2.9711041

Examination

Fact Explanation
Cyanosis [1] Due to large fistula and increased shunting of blood from left to right. Cyanosis may appear marked in upright position due to increased shunting of blood in the upright position.
Clubbing [1] Due to chronic hypoxia.
Telangiectasia [1] Seen in some patients with hereditary hemorrhagic telangiectasia.
Polycythemia [1] In some patients polycythemia can occur as a compensatory method of chronic hypoxia.
Signs of pulmonary hypertension Patients with arteriovenous fistula of pulmonary vessels can develop pulmonary hypertension. Palpable second heart sound and loud pulmonary component of the second heart sound are characteristic of pulmonary hypertension. [1]
Loud pulmonary systolic bruit [1] This is due to large pulmonary arteriovenous fistula. Murmur is most prominent during the inspiration and when the patient is sitting. [2]
Mucocutaneous telangiectasias Pulmonary arteriovenous fistula are seen in about 24% of patients with HHT. [4] Mucocutaneous telangiectasias are commonly seen in HHT. [3]
References
  1. SPERLING D C. Pulmonary arteriovenous fistulas with pulmonary hypertension.. CHEST [online] 1977 June [viewed 05 July 2014] Available from: doi:10.1378/chest.71.6.753
  2. HAZLETT DAVID R.. Postural Effects on the Bruit and Right-to-Left Shunt of Pulmonary Arteriovenous Fistula. Chest [online] 1971 July [viewed 06 July 2014] Available from: doi:10.1378/chest.60.1.89
  3. GOSSAGE JAMES R., KANJ GHASSAN. Pulmonary Arteriovenous Malformations. Am J Respir Crit Care Med [online] 1998 August, 158(2):643-661 [viewed 06 July 2014] Available from: doi:10.1164/ajrccm.158.2.9711041
  4. KJELDSEN AD, OXHøJ H, ANDERSEN PE, GREEN A, VASE P. Prevalence of pulmonary arteriovenous malformations (PAVMs) and occurrence of neurological symptoms in patients with hereditary haemorrhagic telangiectasia (HHT). J Intern Med [online] 2000 Sep, 248(3):255-62 [viewed 06 July 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/10971793

Differential Diagnoses

Fact Explanation
Hereditary hemorrhagic telangiectasia (HHT) HHT is associated with the appearance of telangiectasia and pulmonary arteriovenous malformations. Curaçao criteria are used to establish the diagnosis. [1]
Hepatopulmonary syndrome Hepatopulmonary syndrome is also associated with platypnea. [2]
Pulmonary hypertension Various causes of pulmonary hypertension include, congenital heart defects, connective tissue disease like scleroderma, certain drugs, HIV infection, recurrent pulmonary embolisms, liver disease, and idiopathic pulmonary hypertension. [9]
Ebstein anomaly Ebstein anomaly is a rare congenital cardiac disease. Abnormal embryonic development of the tricuspid valve is the etiology of the disease. [3,4]
Hemothorax Patients with pulmonary arteriovenous malformation can have hemothorax as a complication of the disease. Acute worsening of dyspnea is characteristic. Chest X-ray is helpful in diagnosing. [5]
Anomalous pulmonary venous connection Partial or total anomalous pulmonary venous connection presents with development of cyanosis and reduced exercise tolerance early in the life. [7,8]
Eisenmenger Syndrome Shunt reversal of congenital heart diseases with left-to-right shunts leads to Eisenmenger syndrome. Cyanosis, clubbing, tachypnea, and tachycardia are common. [6]
Schistosomiasis Schistosomiasis is a relatively rare acquired cause of pulmonary arteriovenous fistulae. [2]
References
  1. BEGBIE M, WALLACE G, SHOVLIN C. Hereditary haemorrhagic telangiectasia (Osler-Weber-Rendu syndrome): a view from the 21st century Postgrad Med J [online] 2003 Jan, 79(927):18-24 [viewed 01 July 2014] Available from: doi:10.1136/pmj.79.927.18
  2. GOSSAGE JAMES R., KANJ GHASSAN. Pulmonary Arteriovenous Malformations. Am J Respir Crit Care Med [online] 1998 August, 158(2):643-661 [viewed 06 July 2014] Available from: doi:10.1164/ajrccm.158.2.9711041
  3. ATTENHOFER JOST C. H., CONNOLLY H. M., DEARANI J. A., EDWARDS W. D., DANIELSON G. K.. Ebstein's Anomaly. Circulation [online] 2006 December, 115(2):277-285 [viewed 06 July 2014] Available from: doi:10.1161/CIRCULATIONAHA.106.619338
  4. O'LOUGHLIN AIDEN J., HAYWARD CHRIS. Ebstein's Anomaly. N Engl J Med [online] 2005 September [viewed 06 July 2014] Available from: doi:10.1056/NEJMicm031104
  5. ZHAO YINGHAO, LI GUANG-YU, YANG ZHIGUANG, ZHANG PENG, ZHANG KUN, SHAO GUOGUANG. Bilateral heterochronic spontaneous hemothorax caused by pulmonary arteriovenous malformation in a gravid: A case report. Array [online] 2010 December [viewed 06 July 2014] Available from: doi:10.1186/1749-8090-5-96
  6. WOOD P. The Eisenmenger Syndrome: II Br Med J [online] 1958 Sep 27, 2(5099):755-762 [viewed 06 July 2014] Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2026272
  7. HIRSCH J. C., BOVE E. L.. Total anomalous pulmonary venous connection. Multimedia Manual of Cardio-Thoracic Surgery [online] 2007 January [viewed 06 July 2014] Available from: doi:10.1510/mmcts.2006.002253
  8. AMMASH NASER M, SEWARD JAMES B, WARNES CAROLE A, CONNOLLY HEIDI M, O’LEARY PATRICK W, DANIELSON GORDON K. Partial Anomalous Pulmonary Venous Connection: Diagnosis by Transesophageal Echocardiography. Journal of the American College of Cardiology [online] 1997 May, 29(6):1351-1358 [viewed 06 July 2014] Available from: doi:10.1016/S0735-1097(97)82758-1
  9. BENISTY J. I.. Pulmonary Hypertension. [online] 2002 December, 106(24):192e-194 [viewed 06 July 2014] Available from: doi:10.1161/​01.CIR.0000042762.47822.FE

Investigations - for Diagnosis

Fact Explanation
Full blood count Hemoglobin and hematocrit is elevated in the presence of compensatory polycythemia. Low hemoglobin is rarely seen in patients presenting with massive hemoptysis. [4]
Pulse oxymetry Oxygen saturations is usually less than 95% . Orthodeoxia is referred to decrease in oxygen saturation in upright position. Most of the pulmonary arteriovenous fistula are located at the lower lobes of the lung. Once the patient is in upright position, more blood is flowing through the fistula because of the effect of gravity. This further decreases the oxygenation of blood hence oxygen saturation. [3]
Chest X-ray Pulmonary nodules (round or oval mass of uniform density) are characteristically seen in chest X-ray, prominently in the lower lobes. Chest X-ray can be normal in the presence of small fistula. Rarely the feeding artery can be seen in large fistulae. [4]
Contrast enhanced CT Contrast enhanced CT can visualize the pulmonary vascular tree. Use of 3D helical CT scan can further increases the sensitivity of the CT. [4]
Pulmonary angiography This is the gold standard in diagnosing pulmonary arteriovenous fistula. Angiogram can detect and helps in assessing the site and size of the fistula. Circumscribed dilatation of the pulmonary artery or vein is the characteristic feature seen in angiogram. [1,2,4]
Contrast echocardiography [1] A bubble contrast (micro bubbles of less than 50 microns in diameter) is injected intravenously and the four chambers of the heart is visualized. In normal persons micro bubbles are filtered in the pulmonary capillary bed hence they are not seen in the left atrium and the ventricle. In the presence of pulmonary fistula micro bubbles escape from the pulmonary capillary bed and can be seen in the left atrium and the ventricle. Contrast echocardiography is almost 100% sensitive in detecting pulmonary fistulae.
Radionuclide perfusion lung scan Technetium 99m–labeled macroaggregated albumin is injected intravenously. These are usually filtered in the pulmonary capillary bed. In the presence of fistulae technetium 99m–labeled macroaggregated albumin escapes from the lungs and it is seen in the capillary network in the brain and the kidney as well. This is considered 100% sensitive in detecting pulmonary arteriovenous fistulae. [4]
MRI MRI has relatively low sensitivity in detecting pulmonary fistulae, but use of phase-contrast cine sequences and MR angiography can enhance the sensitivity of MRI. [2,4]
Cardiac catheterization Presence of pulmonary hypertension can be detected. [5,6]
Shunt fraction measurement Shunt fraction is the fraction of cardiac output that shunts from right to left. If it is more than 5% it indicates a significant shunting of blood. [4]
References
  1. KHURSHID I. Pulmonary arteriovenous malformation. [online] 2002 April, 78(918):191-197 [viewed 05 July 2014] Available from: doi:10.1136/pmj.78.918.191
  2. BRIAN C. A., PAYNE R. M., LINK K. M., HUNDLEY W. G., WARNER J. G.. Pulmonary Arteriovenous Malformation. Circulation [online] 1999 July, 100(4):e29-e30 [viewed 06 July 2014] Available from: doi:10.1161/01.CIR.100.4.e29
  3. HAZLETT DAVID R.. Postural Effects on the Bruit and Right-to-Left Shunt of Pulmonary Arteriovenous Fistula. Chest [online] 1971 July [viewed 06 July 2014] Available from: doi:10.1378/chest.60.1.89
  4. GOSSAGE JAMES R., KANJ GHASSAN. Pulmonary Arteriovenous Malformations. Am J Respir Crit Care Med [online] 1998 August, 158(2):643-661 [viewed 06 July 2014] Available from: doi:10.1164/ajrccm.158.2.9711041
  5. PAPAGIANNIS J, APOSTOLOPOULOU S, SARRIS G, RAMMOS S. Diagnosis and management of pulmonary arteriovenous malformations Images Paediatr Cardiol [online] 2002, 4(1):33-49 [viewed 06 July 2014] Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3232512
  6. SANDERS J. S., MARTT J. M.. Multiple Small Pulmonary Arteriovenous Fistulas: Diagnosis by Cardiac Catheterization. Circulation [online] 1962 February, 25(2):383-389 [viewed 06 July 2014] Available from: doi:10.1161/01.CIR.25.2.383

Investigations - Followup

Fact Explanation
Contrast echocardiography [1] Contrast echocardiography helps in detecting the recurrence of pulmonary arteriovenous fistule.
Right heart catheterization Patients are at risk of development of pulmonary hypertension after therapeutic embolization of the fistulae. Presence of pulmonary hypertension can be detected by right heart catheterization. [2]
References
  1. KHURSHID I. Pulmonary arteriovenous malformation. [online] 2002 April, 78(918):191-197 [viewed 05 July 2014] Available from: doi:10.1136/pmj.78.918.191
  2. PAPAGIANNIS J, APOSTOLOPOULOU S, SARRIS G, RAMMOS S. Diagnosis and management of pulmonary arteriovenous malformations Images Paediatr Cardiol [online] 2002, 4(1):33-49 [viewed 06 July 2014] Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3232512

Investigations - Screening/Staging

Fact Explanation
Lung function test Lung function tests are indicated to evaluate the degree of dyspnea. [2]
Exercise ECG This is indicated in the assessment of dyspnea and patient's functionality. [3]
Shunt fraction measurement Shunt fraction measurement helps in the assessment of severity of shunt of blood through the fistula. [1]
References
  1. GOSSAGE JAMES R., KANJ GHASSAN. Pulmonary Arteriovenous Malformations. Am J Respir Crit Care Med [online] 1998 August, 158(2):643-661 [viewed 06 July 2014] Available from: doi:10.1164/ajrccm.158.2.9711041
  2. KARNANI NG, REISFIELD GM, WILSON GR. Evaluation of chronic dyspnea. Am Fam Physician [online] 2005 Apr 15, 71(8):1529-37 [viewed 06 July 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/15864893

Management - General Measures

Fact Explanation
Basic life support Very rarely some patients can present with shock due to massive epistaxis and hemoptysis. Assessment of airway, breathing and circulation should be done first. Airway patency should be maintained in unconscious patients with oropharyngeal airway or with tracheal intubation. Oxygen should be administered if oxygen saturation is low. Blood should be sent to the emergency grouping and cross-matching as soon as possible. Crystalloids are the intravenous fluid of choice for the initial resuscitation followed by colloids till blood is available for the transfusion. [1]
Antibiotic prophylaxis Antibiotic prophylaxis is indicated in all patients with pulmonary AVMs before surgical or dental procedures to minimize the risk of septicemia and septic embolization. [2]
References
  1. BERG R. A., HEMPHILL R., ABELLA B. S., AUFDERHEIDE T. P., CAVE D. M., HAZINSKI M. F., LERNER E. B., REA T. D., SAYRE M. R., SWOR R. A.. Part 5: Adult Basic Life Support: 2010 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care. Circulation [online] December, 122(18_suppl_3):S685-S705 [viewed 02 July 2014] Available from: doi:10.1161/CIRCULATIONAHA.110.970939
  2. SOOD NIDHI, SOOD NIKHIL, DHAWAN VIBHU. Pulmonary Arteriovenous Malformation (AVM) Causing Tension Hemothorax in a Pregnant Woman Requiring Emergent Cesarean Delivery. Pulmonary Medicine [online] 2011 December, 2011:1-3 [viewed 06 July 2014] Available from: doi:10.1155/2011/865195

Management - Specific Treatments

Fact Explanation
Conservative management Patients with severe pulmonary hypertension are not eligible for the resection of pulmonary arteriovenous fistula and conservative management is indicated. [1]
Therapeutic cardiac catheterization Angiographic embolization or balloon occlusion of the feeding artery is one treatment option. Embolization is done with a metal coil. This method does not have a risk of lung parenchymal loss when compared to surgical excision. Induction of tachyarrhythmias, bradyarrhythmias, air embolism and vascular occlusion or rupture is recognized complications. [1,2]
Surgical excision [1] Lung parenchymal resection is now rarely done. Ligation of the feeding artery is preferred over parenchymal resection. Video-assisted thoracoscopic resection is practiced for the treatment of small fistulae.
References
  1. SPERLING D C. Pulmonary arteriovenous fistulas with pulmonary hypertension.. CHEST [online] 1977 June [viewed 05 July 2014] Available from: doi:10.1378/chest.71.6.753
  2. BRIAN C. A., PAYNE R. M., LINK K. M., HUNDLEY W. G., WARNER J. G.. Pulmonary Arteriovenous Malformation. Circulation [online] 1999 July, 100(4):e29-e30 [viewed 06 July 2014] Available from: doi:10.1161/01.CIR.100.4.e29