Congenital intrahepatic portosystemic shunt-an incidental rare anomaly
http://www.100md.com
《美国医学杂志》
Advanced Diagnostics and Institute of Imaging, 17/8 Kennedy Avenue, Arnritsar 143001, Punjab, India
Congenital intrahepatic shunts are rare anomalies that are usually incidental in a child who undergoes an ultrasound examination for some other reasons. Early diagnosis is important, because the condition can lead to hepatic encephalopathy and hypoglycemia. Author's would like to describe the findings of one such patient diagnosed to be having congenital intrahepatic shunt and discuss the clinical importance of this condition.
Keywords: Congenital; Intrahepatic shunts; Anomalies; Ultrasound
Congenital intrahepatic shunts are rare a symptomatic anomalies which in the later life can lead to. hepatic encephalopathy. Early and accurate diagnosis is important to prevent misdiagnosis of the condition as a psychiatric or neurological disorder. It is therefore, important in a child presenting with such like .symptoms to be aware of this condition. Evaluation and subsequent confirmation of diagnosis is done by the use of imaging.[1]
Ultrasound examination demonstrates abnormal anechoic structures communicating between the portal venous branches and the hepatic veins while Color Doppler imaging (CDI) shows the presence of a tri-phasic or biphasic spectral pattern in the portal and splenic veins which suggests the presence of portosystemic shunt.[1]
Case report
A 4-year-old male child presented to autors with a short history of painful micturition with no relevant past history. Routine hematology and biochemical examination was normal while urine complete examination showed many pus cells. Ultrasound of the abdomen showed. normal size and echotexture of the liver along with a small communicating anechoic tubular structure between the right branch of portal vein and the Inferior venacava [Figure - 1]. On CDI the presence of the shunt was confirmed and a pulsatile flow was seen in the portal vein along with the presence of color flow signals in the above visualised tubular channel [Figure - 2]a and b. Diagnosis of a congenital intrahepatic portal shunt (Park type-I) was made. The calculated shunt ratio was 27%.
Serum ammonia levels were done which were nonnal.(22 micromoles/litre) (Nonnal range: 11-35 micromoles/litre)
Rest of the abdomen was unremarkable. There was no history of any kind of liver biopsy or any interventional procedure done earlier hence the above vascular. malfonnation was believed to be a congenital anomaly which was an incidental finding and was a symptomatic at the time of diagnosis.
Discussion
Congenital intrahepatic shunts have been classified on the basis of Parks classification into five morphological types(2):Type I - Single large shunt with a constant diameter that connects the right portal vein to inferior vena cava. Type II-localised peripheral shunt in which single or multiple communication are found between peripheral branches of portal vein and hepatic veins in one hepatic segment. Type III - peripheral portal and hepatic veins are connected through an aneurysm. Type IV-multiple communications exist between portal and hepatic veins in both the lobes and Type V with persistent ductus venosus.
CDI is an important tool for confirming the vascular nature of the tubular structure and shows the color flow signals in the shunt alongwith changes in the blood flow pattern in the main portal vein which becomes more pulsatile. CDI is also helpful in calculating the blood flow volumes and portosystemic shunt ratio.[1] Blood flow volumes are measured by multiplying the lumen area by mean velocity at a given point. The portovenous shunt ratio is calculated by: Total blood flow volume in the shunt/Total blood flow volume in the portal vein. If this ratio is more than 60%, it carries an increased risk for hepatic encephalopathy and is an indication for a corrective procedures like coil embolisation to occlude the shunt.[3] If the shunt ratio is low then such patients are to be observed clinically and a regular follow up is suggested as many of the shunts undergo spontaneous closure by five years of age. The role of other modalities like CT and MRI scan is not clearly defined.[4],[5]
The importance of reporting this case is not only in knowing the rarity of condition but in highlighting the usefulness of non-invasive imaging like Ultrasonography and CDI in detecting the condition 'and can obviate the need for doing more expensive and invasive tests like scintigraphy.
References
1.Kudo M, Tomita S, Tochio H, Minowa K, Todo A. Intrahepatic porto systemic venous shunt: diagnosis by color Doppler imaging. Am J Gastroenterol 1993; 88: 723-737. [PUBMED]
2.Park JH, Cha SH, Han JK, Ran MC. Intrahepatic porto systemic venous shunt. AJR Am J Roentgenol 2000; 155: 527-528.
3.Maeda T, Mori H, Aikawa H, Komatsu E. Therapeutic emboliosation of intrahepatic porto systemic shunts by retrograde transcaval catheterization. Cardiovascular Intervent Radiol 1993; 16 : 245-247.
4.Kakitsubata Y, Kakitsubata S, Kiyomizu H, Ogawa T, Kato K, Watanbe K. Intrahepatic porto-hepatic venous shunts demonstrated by US, CT & MR imaging. Acta Radio l 1996; Sep; 37(5) : 680-680.
5.Carmen Gallego, MD, Maria Miralles, MD. Carlos Marin, MD. Purificacion Muyor, MD. Gabino Gonzalez, MD. Enrique Garcia-Hidalgo, MD. Congenital hepatic shunts. Radio Graphics 2004; 24 : 767.(Singh Kunwarpal, Kapoor Aprajita, Kapoor)
Congenital intrahepatic shunts are rare anomalies that are usually incidental in a child who undergoes an ultrasound examination for some other reasons. Early diagnosis is important, because the condition can lead to hepatic encephalopathy and hypoglycemia. Author's would like to describe the findings of one such patient diagnosed to be having congenital intrahepatic shunt and discuss the clinical importance of this condition.
Keywords: Congenital; Intrahepatic shunts; Anomalies; Ultrasound
Congenital intrahepatic shunts are rare a symptomatic anomalies which in the later life can lead to. hepatic encephalopathy. Early and accurate diagnosis is important to prevent misdiagnosis of the condition as a psychiatric or neurological disorder. It is therefore, important in a child presenting with such like .symptoms to be aware of this condition. Evaluation and subsequent confirmation of diagnosis is done by the use of imaging.[1]
Ultrasound examination demonstrates abnormal anechoic structures communicating between the portal venous branches and the hepatic veins while Color Doppler imaging (CDI) shows the presence of a tri-phasic or biphasic spectral pattern in the portal and splenic veins which suggests the presence of portosystemic shunt.[1]
Case report
A 4-year-old male child presented to autors with a short history of painful micturition with no relevant past history. Routine hematology and biochemical examination was normal while urine complete examination showed many pus cells. Ultrasound of the abdomen showed. normal size and echotexture of the liver along with a small communicating anechoic tubular structure between the right branch of portal vein and the Inferior venacava [Figure - 1]. On CDI the presence of the shunt was confirmed and a pulsatile flow was seen in the portal vein along with the presence of color flow signals in the above visualised tubular channel [Figure - 2]a and b. Diagnosis of a congenital intrahepatic portal shunt (Park type-I) was made. The calculated shunt ratio was 27%.
Serum ammonia levels were done which were nonnal.(22 micromoles/litre) (Nonnal range: 11-35 micromoles/litre)
Rest of the abdomen was unremarkable. There was no history of any kind of liver biopsy or any interventional procedure done earlier hence the above vascular. malfonnation was believed to be a congenital anomaly which was an incidental finding and was a symptomatic at the time of diagnosis.
Discussion
Congenital intrahepatic shunts have been classified on the basis of Parks classification into five morphological types(2):Type I - Single large shunt with a constant diameter that connects the right portal vein to inferior vena cava. Type II-localised peripheral shunt in which single or multiple communication are found between peripheral branches of portal vein and hepatic veins in one hepatic segment. Type III - peripheral portal and hepatic veins are connected through an aneurysm. Type IV-multiple communications exist between portal and hepatic veins in both the lobes and Type V with persistent ductus venosus.
CDI is an important tool for confirming the vascular nature of the tubular structure and shows the color flow signals in the shunt alongwith changes in the blood flow pattern in the main portal vein which becomes more pulsatile. CDI is also helpful in calculating the blood flow volumes and portosystemic shunt ratio.[1] Blood flow volumes are measured by multiplying the lumen area by mean velocity at a given point. The portovenous shunt ratio is calculated by: Total blood flow volume in the shunt/Total blood flow volume in the portal vein. If this ratio is more than 60%, it carries an increased risk for hepatic encephalopathy and is an indication for a corrective procedures like coil embolisation to occlude the shunt.[3] If the shunt ratio is low then such patients are to be observed clinically and a regular follow up is suggested as many of the shunts undergo spontaneous closure by five years of age. The role of other modalities like CT and MRI scan is not clearly defined.[4],[5]
The importance of reporting this case is not only in knowing the rarity of condition but in highlighting the usefulness of non-invasive imaging like Ultrasonography and CDI in detecting the condition 'and can obviate the need for doing more expensive and invasive tests like scintigraphy.
References
1.Kudo M, Tomita S, Tochio H, Minowa K, Todo A. Intrahepatic porto systemic venous shunt: diagnosis by color Doppler imaging. Am J Gastroenterol 1993; 88: 723-737. [PUBMED]
2.Park JH, Cha SH, Han JK, Ran MC. Intrahepatic porto systemic venous shunt. AJR Am J Roentgenol 2000; 155: 527-528.
3.Maeda T, Mori H, Aikawa H, Komatsu E. Therapeutic emboliosation of intrahepatic porto systemic shunts by retrograde transcaval catheterization. Cardiovascular Intervent Radiol 1993; 16 : 245-247.
4.Kakitsubata Y, Kakitsubata S, Kiyomizu H, Ogawa T, Kato K, Watanbe K. Intrahepatic porto-hepatic venous shunts demonstrated by US, CT & MR imaging. Acta Radio l 1996; Sep; 37(5) : 680-680.
5.Carmen Gallego, MD, Maria Miralles, MD. Carlos Marin, MD. Purificacion Muyor, MD. Gabino Gonzalez, MD. Enrique Garcia-Hidalgo, MD. Congenital hepatic shunts. Radio Graphics 2004; 24 : 767.(Singh Kunwarpal, Kapoor Aprajita, Kapoor)