eMedicine Specialties > Gastroenterology > Liver

Portal Vein Obstruction

Author: Adnan Said, MD, MSPH, Assistant Professor, Department of Medicine, Section of Gastroenterology and Hepatology, University of Wisconsin School of Medicine and Public Health at Madison; Consulting Staff, Department of Medicine, William S Middleton Memorial Veterans Hospital
Coauthor(s): Jennifer T Wells, MD, Fellow, Department of Gastroenterology and Hepatology, University of Wisconsin Hospitals and Clinics, Madison
Contributor Information and Disclosures

Updated: Aug 25, 2009

Introduction

Background

In the English literature, portal vein obstruction was first reported in 1868 by Balfour and Stewart, who described a patient presenting with an enlarged spleen, ascites, and variceal dilatation.

The vast majority of cases are due to primary thrombosis of the portal vein; most of the remaining cases are caused by malignant obstruction.

Portal vein thrombosis with cavernous transformat...

Portal vein thrombosis with cavernous transformation. The long arrow indicates the splenic vein at the junction with the superior mesenteric vein just below the site of thrombosis. The short arrow points to a serpiginous mass consistent with periportal collaterals, the so-called cavernous transformation of the portal vein.

[ CLOSE WINDOW ]
Portal vein thrombosis with cavernous transformat...

Portal vein thrombosis with cavernous transformation. The long arrow indicates the splenic vein at the junction with the superior mesenteric vein just below the site of thrombosis. The short arrow points to a serpiginous mass consistent with periportal collaterals, the so-called cavernous transformation of the portal vein.



Hepatocellular carcinoma with portal vein thrombo...

Hepatocellular carcinoma with portal vein thrombosis. The short arrow indicates the tumor thrombus with an abrupt cut off of the portal vein. The long arrow points to a compensatory, prominent left hepatic arterial branch.

[ CLOSE WINDOW ]
Hepatocellular carcinoma with portal vein thrombo...

Hepatocellular carcinoma with portal vein thrombosis. The short arrow indicates the tumor thrombus with an abrupt cut off of the portal vein. The long arrow points to a compensatory, prominent left hepatic arterial branch.

Pathophysiology

The portal vein forms at the junction of the splenic vein and the superior mesenteric vein behind the pancreatic head, and it can become thrombosed or obstructed at any point along its course. In cirrhosis and hepatic malignancies, the thromboses usually begin intrahepatically and spread to the extrahepatic portal vein. In most other etiologies, the thromboses usually start at the site of origin of the portal vein. Occasionally, thrombosis of the splenic vein propagates to the portal vein, most often resulting from an adjacent inflammatory process such as chronic pancreatitis.

Inherited and acquired disorders of the coagulation pathway are frequent causes of portal vein thrombosis. Inherited disorders include mutations in the prothrombin gene G20210A as well as deficiencies of various intrinsic anticoagulation factors, such as protein C and protein S, and activated protein C resistance. Acquired disorders include antithrombin III deficiency resulting from malnutrition, sepsis, disseminated intravascular coagulation, inflammatory bowel disease, liver disease, or estrogen use.


Coagulation disorders in portal vein thrombosis.

Coagulation disorders in portal vein thrombosis.

[ CLOSE WINDOW ]
Coagulation disorders in portal vein thrombosis.

Coagulation disorders in portal vein thrombosis.



Stasis can be another major category for portal vein thrombosis. The global resistance to hepatic blood flow produced by cirrhosis is a common cause. Sclerotherapy for esophageal varices has been postulated as a possible mechanism though not proven thus far. The portal vein or its tributaries can be obstructed by adjacent tumor compression or invasion. Infectious and inflammatory processes may also lead to venous thrombosis.

Portal vein obstruction does not affect liver function unless the patient has an underlying liver disease such as cirrhosis.1 This is partially due to a rapid arterial buffer response, with compensatory increased flow of the hepatic artery maintaining the total hepatic blood flow. Formation of collaterals occurs rather rapidly as well, and they have been described as early as 12 days after acute thrombosis, though the average time to formation is approximately 5 weeks.

The development of a collateral circulation, with its attendant risk of variceal hemorrhage, is responsible for most of the complications and is the most common manifestation of portal vein obstruction. Other sequelae of the subsequent portal hypertension, such as ascites, are less frequent. Rarely, the thrombosis extends from the portal vein to the mesenteric arcades, leading to bowel ischemia and infarction.

Frequency

United States

Portal vein obstruction is a relatively rare condition with an overall incidence of 0.05-0.5% in autopsy studies. Incidence varies, depending on the group of patients studied (eg, general population vs patients with cirrhosis) and the method used to diagnose portal vein obstruction (eg, autopsy studies, angiography studies, noninvasive radiological screening).

Incidence of portal vein obstruction in people with cirrhosis has been reported to vary from 5-18%. However, these were patients referred for transplantation and were at an advanced stage of liver disease. No large autopsy studies are available. Extrahepatic portal vein obstruction is estimated to be responsible for 5-10% of all cases of portal hypertension.

International

In Japan, the frequency of portal vein obstruction in autopsy studies was reported to be 0.05%. In an angiography surveillance study of patients with cirrhosis, the incidence was 0.5%, which is much lower than the reported incidence in the Western literature.

In India, extrahepatic portal vein obstruction is reported more frequently; in one study, the incidence even exceeded reported cases of cirrhosis. Of all cases of portal hypertension in developing countries, 40% are attributed to portal vein obstruction, presumably secondary to an increased incidence of pylephlebitis associated with abdominal infections.

Mortality/Morbidity

  • In the absence of cirrhosis, the 2 year bleeding risk from esophageal varices is reported to be 0.25% and of those that bleed the mortality rate is approximately 5%. Those with cirrhosis and varices have a 20-30% 2 year bleeding risk with a mortality rate of 30-70%. This difference is primarily a consequence of the normal hepatic function in the noncirrhotic patient. Variceal size is the major predictive factor for bleeding.
  • In adults with portal vein thrombosis, the 10-year survival rate has been reported to be 38-60%, with most of the deaths occurring secondary to the underlying disease (eg, cirrhosis, malignancy).
  • In children with portal vein thrombosis, the prognosis is much better overall, with a 10-year survival rate greater than 70%, which is attributable to the low incidence of underlying malignancy and cirrhosis.

Race

No racial differences have been reported.

Sex

No sex differences have been reported overall, except for a slight male predominance in patients whose obstruction is secondary to cirrhosis.

Age

  • The distribution of the age of presentation of portal vein thrombosis reflects the demographics of the underlying disease process. Primary portal vein thrombosis from coagulopathies occurs with equal frequency in adults and children.2 The frequency of portal vein obstruction from tumor compression or invasion is greater in adults.

Clinical

History

In the acute phase, the presentation of portal vein obstruction is relatively uncommon and easily missed because the patient may be asymptomatic. Symptoms most often begin in the chronic or subacute stage. Schistosomiasis can cause presinusoidal portal obstruction by blocking intrahepatic portal venules with parasite eggs. It does not cause extrahepatic portal vein obstruction, though the clinical manifestations are often similar.

  • Acute
    • Patients can present emergently with sudden onset of right upper quadrant pain, nausea, and/or fever. Alternatively, the symptoms of the primary infectious and inflammatory condition that led to portal vein obstruction predominate (eg, right lower quadrant pain in appendicitis).
    • Progressive ascites, intestinal ischemia resulting from propagation of thrombus, or intestinal suffusion secondary to acute portal hypertension can also be the presenting manifestations. Occasionally, variceal bleeding can occur acutely with development of portal vein thrombosis, particularly in the setting of preexisting varices with cirrhosis.
    • Spontaneous resolution of acute/recent thrombosis undoubtedly occurs and symptoms abate. In other patients, the acute symptoms often subside as collaterals develop, and the diagnosis may be missed. These patients then present at a later stage with manifestations of portal hypertension.
  • Chronic
    • These groups of patients most often present with complications related to portal hypertension. In 90% of cases, variceal bleeding is the presenting complaint. On average, this occurs 4 years after the thrombotic event and has been described as long as 12 years later. Ascites is less frequent, and hepatic encephalopathy is rare in the absence of preexisting cirrhosis.3
    • The specific etiology of the portal vein obstruction not only influences the initial clinical presentation but also the time course and prognosis.
    • In the presence of cirrhosis with underlying hepatic insufficiency, sudden worsening of hepatic function, development of hepatic encephalopathy, and development of ascites are all more frequent, leading to worse outcomes.
    • With intra-abdominal malignancies, bleeding is less commonly the first manifestation because many of these patients do not survive long enough to develop sequelae of portal hypertension. These patients most often present with sudden ascites, anorexia, right upper quadrant or epigastric pain, and weight loss. Portal vein obstruction may also be discovered incidentally on imaging studies obtained for pain or ascites.
    • Rarely, patients with portal vein obstruction present with a fever of unknown origin.

Physical

  • Splenomegaly is found in 75-100% of patients, most presenting in the chronic stage. Mild hepatomegaly is often present, as is right upper quadrant epigastric tenderness, especially in the acute setting.
  • Ascites is found infrequently. Stigmata of chronic liver disease, such as spider angiomata or palmar erythema, are usually found in the presence of underlying liver disease.
  • The presence of caput medusae indicates posthepatic or intrahepatic portal hypertension because it forms by recanalization of the umbilical vein, which connects with the left hepatic branch of the portal vein.4 It should not be observed in isolated extrahepatic portal vein obstruction because the obstruction is below the origin of the umbilical vein.
  • In children, growth retardation may be present.27
  • Abnormalities of the extrahepatic biliary tree may occur in 80% of cases due to compression by choledochal or periportal varices or from ischemic stricturing. These findings manifest by jaundice, cholangitis, hemobilia, cholecystitis, or a hilar mass that can be mistaken for a cholangiocarcinoma.

Causes

  • Children
    • In children and neonates, the most common etiology is intra-abdominal infection, accounting for 50% of all cases in this age group.
    • In this age group, neonatal sepsis with umbilical catheter placement has been reported to be the cause of portal vein thrombosis in 10-26% of cases.
    • Appendicitis is a commonly reported risk factor in children with portal vein thrombosis.
    • Congenital anomalies of the portal venous system, often associated with cardiovascular anomalies (eg, ventricular and atrial septal defects, deformed inferior vena cava) and biliary tract abnormalities, have been reported in 20% of children with portal vein obstruction and thrombosis.
  • Adults
    • In adults, cirrhosis is the major etiology, accounting for 24-32% of cases of portal vein thrombosis.
    • Neoplasms are another major cause, accounting for 21-24% of cases of portal vein obstruction, with hepatocellular carcinoma and pancreatic carcinoma causing most of these cases. These tumors can cause compression or direct invasion of the portal vein and lead to thrombosis by inducing a hypercoagulable state.5 Local ablative therapies for hepatocellular or metastatic disease have been linked to its development.
    • Although less common than in children, infections (predominantly intra-abdominal) still play an important role, with a particular association to Bacteroides fragilis bacteremia.
    • Myeloproliferative disorders and inherited or acquired coagulation disorders account for 10-12% of cases in adults.
    • Approximately 8-15% of cases have been reported to be idiopathic in the recent literature. For other less common etiologies, such as abdominal trauma, surgery, and inflammatory bowel disease, see Media file 1 or below.
      The etiology of portal vein obstruction.

      The etiology of portal vein obstruction.

      [ CLOSE WINDOW ]
      The etiology of portal vein obstruction.

      The etiology of portal vein obstruction.

More on Portal Vein Obstruction

Overview: Portal Vein Obstruction
Differential Diagnoses & Workup: Portal Vein Obstruction
Treatment & Medication: Portal Vein Obstruction
Follow-up: Portal Vein Obstruction
Multimedia: Portal Vein Obstruction
References
Further Reading
[ CLOSE WINDOW ]

References

  1. Chawla Y, Dhiman RK. Intrahepatic portal venopathy and related disorders of the liver. Semin Liver Dis. Aug 2008;28(3):270-81. [Medline].

  2. Abd El-Hamid N, Taylor RM, Marinello D, Mufti GJ, Patel R, Mieli-Vergani G, et al. Aetiology and management of extrahepatic portal vein obstruction in children: King's College Hospital experience. J Pediatr Gastroenterol Nutr. Nov 2008;47(5):630-4. [Medline].

  3. Sharma P, Sharma BC, Puri V, Sarin SK. Natural history of minimal hepatic encephalopathy in patients with extrahepatic portal vein obstruction. Am J Gastroenterol. Apr 2009;104(4):885-90. [Medline].

  4. Facciuto ME, Rodriguez-Davalos MI, Singh MK, Rocca JP, Rochon C, Chen W, et al. Recanalized umbilical vein conduit for meso-Rex bypass in extrahepatic portal vein obstruction. Surgery. Apr 2009;145(4):406-10. [Medline].

  5. Liu Q, Chen J, Li H, Liang B, Zhang L, Hu T. Hepatocellular carcinoma with bile duct tumor thrombi: Correlation of magnetic resonance imaging features to histopathologic manifestations. Eur J Radiol. Jun 5 2009;[Medline].

  6. Albertyn LE. Acute portal vein thrombosis. Clin Radiol. Nov 1987;38(6):645-8. [Medline].

  7. Balfour GW, Stewart TG. Case of enlarged spleen complicated with ascites, both depending upon varicose dilatation and thrombosis of the portal vein. Edinburgh Med Journal. 1869;14:589-598.

  8. Belli L, Romani F, Riolo F, et al. Thrombosis of portal vein in absence of hepatic disease. Surg Gynecol Obstet. Jul 1989;169(1):46-9. [Medline].

  9. Bildozola M, Kravetz D, Argonz J. Efficacy of octreotide and sclerotherapy in the treatment of acute variceal bleeding in cirrhotic patients. A prospective, multicentric, and randomized clinical trial. Scand J Gastroenterol. Apr 2000;35(4):419-25. [Medline].

  10. Bircher J, Benhamou JP, McIntyre N. Oxford Textbook of Clinical Hepatology. 2nd ed. 1999: 601, 1463-7, 1807-8, 1885-6, 2057-8.

  11. Blum U, Haag K, Rossle M, et al. Noncavernomatous portal vein thrombosis in hepatic cirrhosis: treatment with transjugular intrahepatic portosystemic shunt and local thrombolysis. Radiology. Apr 1995;195(1):153-7. [Medline].

  12. Charco R, Fuster J, Fondevila C. Portal vein thrombosis in liver transplantation. Transplant Proc. Nov 2005;37(9):3904-5. [Medline].

  13. Cohen J, Edelman RR, Chopra S. Portal vein thrombosis: a review. Am J Med. Feb 1992;92(2):173-82. [Medline].

  14. Dubuisson C, Boyer-Neumann C, Wolf M. Protein C, protein S and antithrombin III in children with portal vein obstruction. J Hepatol. Jul 1997;27(1):132-5. [Medline].

  15. Egesel T, Buyukasik Y, Dundar SV, et al. The role of natural anticoagulant deficiencies and factor V Leiden in the development of idiopathic portal vein thrombosis. J Clin Gastroenterol. Jan 2000;30(1):66-71. [Medline].

  16. Ganger DR, Klapman JB, McDonald V, et al. Transjugular intrahepatic portosystemic shunt (TIPS) for Budd-Chiari syndrome or portal vein thrombosis: review of indications and problems. Am J Gastroenterol. Mar 1999;94(3):603-8. [Medline].

  17. Gimeno FA, Calvo J, Loinaz C. Comparative analysis of the results of orthotopic liver transplantation in patients with and without portal vein thrombosis. Transplant Proc. Nov 2005;37(9):3899-903. [Medline].

  18. Hidajat N, Stobbe H, Griesshaber V. Imaging and radiological interventions of portal vein thrombosis. Acta Radiol. Jul 2005;46(4):336-43. [Medline].

  19. Kaplan KL. Case 22-1991: portal-vein thrombosis. N Engl J Med. Nov 7 1991;325(19):1384. [Medline].

  20. Kim HB, Pomposelli JJ, Lillehei CW. Mesogonadal shunts for extrahepatic portal vein thrombosis and variceal hemorrhage. Liver Transpl. Nov 2005;11(11):1389-94. [Medline].

  21. Laishram H, Cramer B, Kennedy R. Idiopathic acute portal vein thrombosis: a case report. J Pediatr Surg. Sep 1993;28(9):1106-8. [Medline].

  22. Macpherson AI. Portal hypertension due to extrahepatic portal venous obstruction. A review of 40 cases. J R Coll Surg Edinb. Jan 1984;29(1):4-10. [Medline].

  23. Maddrey WC, Sen Gupta KP, Mallik KC, et al. Extrahepatic obstruction of the portal venous system. Surg Gynecol Obstet. Nov 1968;127(5):989-98. [Medline].

  24. Mangia A, Villani MR, Cappucci G. Causes of portal venous thrombosis in cirrhotic patients: the role of genetic and acquired factors. Eur J Gastroenterol Hepatol. Jul 2005;17(7):745-51. [Medline].

  25. Merkel C, Bolognesi M, Bellon S. Long-term follow-up study of adult patients with non-cirrhotic obstruction of the portal system: comparison with cirrhotic patients. J Hepatol. Jul 1992;15(3):299-303. [Medline].

  26. Miyazaki Y, Shinomura Y, Kitamura S, et al. Portal vein thrombosis associated with active ulcerative colitis: percutaneous transhepatic recanalization. Am J Gastroenterol. Sep 1995;90(9):1533-4. [Medline].

  27. Nihal L, Bapat MR, Rathi P, Shah NS, Karvat A, Abraham P, et al. Relation of insulin-like growth factor-1 and insulin-like growth factor binding protein-3 levels to growth retardation in extrahepatic portal vein obstruction. Hepatol Int. Mar 2009;3(1):305-9. [Medline].

  28. Okuda K, Ohnishi K, Kimura K. Incidence of portal vein thrombosis in liver cirrhosis. An angiographic study in 708 patients. Gastroenterology. Aug 1985;89(2):279-86. [Medline].

  29. Orozco H, Takahashi T, Garcia-Tsao G. A comparative clinical study of idiopathic portal hypertension, extrahepatic portal vein thrombosis, and cirrhosis. J Clin Gastroenterol. Oct 1994;19(3):217-21. [Medline].

  30. Orozco H, Takahashi T, Mercado MA, et al. Surgical management of extrahepatic portal hypertension and variceal bleeding. World J Surg. Mar-Apr 1994;18(2):246-50. [Medline].

  31. Parvey HR, Raval B, Sandler CM. Portal vein thrombosis: imaging findings. AJR Am J Roentgenol. Jan 1994;162(1):77-81. [Medline].

  32. Pirisi M, Avellini C, Fabris C, et al. Portal vein thrombosis in hepatocellular carcinoma: age and sex distribution in an autopsy study. J Cancer Res Clin Oncol. 1998;124(7):397-400. [Medline].

  33. Politoske D, Ralls P, Korula J. Portal vein thrombosis following endoscopic variceal sclerotherapy. Prospective controlled comparison in patients with cirrhosis. Dig Dis Sci. Jan 1996;41(1):185-90. [Medline].

  34. Primignani M, Martinelli I, Bucciarelli P. Risk factors for thrombophilia in extrahepatic portal vein obstruction. Hepatology. Mar 2005;41(3):603-8. [Medline].

  35. Robson SC, Kahn D, Kruskal J, et al. Disordered hemostasis in extrahepatic portal hypertension. Hepatology. Oct 1993;18(4):853-7. [Medline].

  36. Sarin SK, Lamba GS, Kumar M. Comparison of endoscopic ligation and propranolol for the primary prevention of variceal bleeding. N Engl J Med. Apr 1 1999;340(13):988-93. [Medline].

  37. Schiff ER, Sorrell MF, Maddrey WC. Schiff's Diseases of the Liver. 8th ed. 1999: 279-80, 509-10, 1479-80.

  38. Scully RE, Mark EJ, McNelly WF. Case records of the Massachusetts General Hospital. Weekly clinicopathological exercises. Case 22-1991. A 15-year-old boy with fever of unknown origin, severe anemia, and portal-vein thrombosis. N Engl J Med. May 30 1991;324(22):1575-84. [Medline].

  39. Seu P, Shackleton CR, Shaked A. Improved results of liver transplantation in patients with portal vein thrombosis. Arch Surg. Aug 1996;131(8):840-4; discussion 844-5. [Medline].

  40. Sheen CL, Lamparelli H, Milne A, et al. Clinical features, diagnosis and outcome of acute portal vein thrombosis. QJM. Aug 2000;93(8):531-4. [Medline].

  41. Sherlock S. Extrahepatic portal venous hypertension in adults. Clin Gastroenterol. Jan 1985;14(1):1-19. [Medline].

  42. Tanaka K, Numata K, Okazaki H, et al. Diagnosis of portal vein thrombosis in patients with hepatocellular carcinoma: efficacy of color Doppler sonography compared with angiography. AJR Am J Roentgenol. Jun 1993;160(6):1279-83. [Medline].

  43. Taylor CR. Computed tomography in the evaluation of the portal venous system. J Clin Gastroenterol. Mar 1992;14(2):167-72. [Medline].

  44. Taylor CR, McCauley TR. Magnetic resonance imaging in the evaluation of the portal venous system. J Clin Gastroenterol. Apr 1992;14(3):268-73. [Medline].

  45. Valla DC, Condat B. Portal vein thrombosis in adults: pathophysiology, pathogenesis and management. J Hepatol. May 2000;32(5):865-71. [Medline].

  46. Vianna R, Giovanardi RO, Fridell JA. Multivisceral transplantation for diffuse portomesenteric thrombosis in a patient with life-threatening esophagogastroduodenal bleeding. Transplantation. Aug 27 2005;80(4):534-5. [Medline].

  47. Wang LY, Lin ZY, Chang WY, et al. Duplex pulsed Doppler sonography of portal vein thrombosis in hepatocellular carcinoma. J Ultrasound Med. May 1991;10(5):265-9. [Medline].

  48. Webb LJ, Sherlock S. The aetiology, presentation and natural history of extra-hepatic portal venous obstruction. Q J Med. Oct 1979;48(192):627-39. [Medline].

  49. Webster GJ, Burroughs AK, Riordan SM. Review article: portal vein thrombosis -- new insights into aetiology and management. Aliment Pharmacol Ther. Jan 1 2005;21(1):1-9. [Medline].

  50. Yerdel MA, Gunson B, Mirza D, et al. Portal vein thrombosis in adults undergoing liver transplantation: risk factors, screening, management, and outcome. Transplantation. May 15 2000;69(9):1873-81. [Medline].

  51. Guerin F, Porras J, Fabre M, et al. Liver nodules after portal systemic shunt surgery for extrahepatic portal vein obstruction in children. J Pediatr Surg. Jul 2009;44(7):1337-43. [Medline]. [Full Text].

[ CLOSE WINDOW ]

Further Reading

Related eMedicine Topics

Clinical Trials
 National Guideline Clearinghouse

[ CLOSE WINDOW ]

Keywords

portal vein obstruction, portal vein thrombosis, PVT, transjugular intrahepatic portosystemic shunt, TIPS, liver transplant, orthotopic liver transplantation, OLT, cirrhosis, splenomegaly, hepatomegaly, hepatocellular carcinoma, pancreatic carcinoma, myeloproliferative disorders, coagulation disorders, anticoagulation therapy, tissue-type plasminogen activator, tPA

[ CLOSE WINDOW ]

Contributor Information and Disclosures

Author

Adnan Said, MD, MSPH, Assistant Professor, Department of Medicine, Section of Gastroenterology and Hepatology, University of Wisconsin School of Medicine and Public Health at Madison; Consulting Staff, Department of Medicine, William S Middleton Memorial Veterans Hospital
Adnan Said, MD, MSPH is a member of the following medical societies: American Association for the Study of Liver Diseases, American Gastroenterological Association, and American Society of Transplantation
Disclosure: Nothing to disclose.

Coauthor(s)

Jennifer T Wells, MD, Fellow, Department of Gastroenterology and Hepatology, University of Wisconsin Hospitals and Clinics, Madison
Jennifer T Wells, MD is a member of the following medical societies: American Medical Association and Phi Beta Kappa
Disclosure: Nothing to disclose.

Medical Editor

Ann Ouyang, MBBS, Professor, Department of Internal Medicine, Pennsylvania State University College of Medicine; Attending Physician, Division of Gastroenterology and Hepatology, Milton S Hershey Medical Center
Disclosure: Nothing to disclose.

Pharmacy Editor

Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine
Disclosure: eMedicine Salary Employment

Managing Editor

Noel Williams, MD, Professor Emeritus, Department of Medicine, Dalhousie University, Halifax, Nova Scotia, Canada; Professor, Department of Internal Medicine, Division of Gastroenterology, University of Alberta, Edmonton, Alberta, Canada
Noel Williams, MD is a member of the following medical societies: Royal College of Physicians and Surgeons of Canada
Disclosure: Nothing to disclose.

CME Editor

Alex J Mechaber, MD, FACP, Associate Dean for Undergraduate Medical Education, Associate Professor of Medicine, University of Miami Miller School of Medicine
Alex J Mechaber, MD, FACP is a member of the following medical societies: Alpha Omega Alpha, American College of Physicians-American Society of Internal Medicine, and Society of General Internal Medicine
Disclosure: Nothing to disclose.

Chief Editor

Julian Katz, MD, Clinical Professor of Medicine, Drexel University College of Medicine; Consulting Staff, Department of Medicine, Section of Gastroenterology and Hepatology, Hospital of the Medical College of Pennsylvania
Julian Katz, MD is a member of the following medical societies: American College of Gastroenterology, American College of Physicians, American Gastroenterological Association, American Geriatrics Society, American Medical Association, American Society for Gastrointestinal Endoscopy, American Society of Law Medicine and Ethics, American Trauma Society, Association of American Medical Colleges, and Physicians for Social Responsibility
Disclosure: Nothing to disclose.

RELATED MEDSCAPE ARTICLES
Articles
 
 
HONcode

We subscribe to the
HONcode principles of the
Health On the Net Foundation

All material on this website is protected by copyright, Copyright© 1994- by Medscape.
This website also contains material copyrighted by 3rd parties.

DISCLAIMER: The content of this Website is not influenced by sponsors. The site is designed primarily for use by qualified physicians and other medical professionals. The information contained herein should NOT be used as a substitute for the advice of an appropriately qualified and licensed physician or other health care provider. The information provided here is for educational and informational purposes only. In no way should it be considered as offering medical advice. Please check with a physician if you suspect you are ill.