Page 409 - First Aid for the USMLE Step 1 2020, Thirtieth edition [MedicalBooksVN.com]_Neat

Gastrointestinal ` gastrointestinal—anatomy Gastrointestinal ` gastrointestinal—anatomy seCtion iii 365

Portosystemic
anastomoses

Azygos vein Pathologic blood in portal HTN
Esophageal vein Flow through TIPS, re-establishing
normal flow direction
IVC Q
Normal venous drainage
Shunt Systemic venous system
Left gastric vein
Portal venous system
Portal vein
Splenic vein
Paraumbilical vein
Superior mesenteric vein
Inferior mesenteric vein
R
Umbilicus
Colon

Superior rectal vein
(superior hemorrhoidal vein)
Epigastric veins
Middle rectal vein
Inferior rectal vein
S
Anus

site oF anastomosis CliniCal sign Portal ↔ systemiC
Esophagus Esophageal varices Left gastric ↔ esophageal
(drains into azygos)
Umbilicus Caput medusae Paraumbilical ↔ small
epigastric veins of the anterior
abdominal wall.
Rectum Anorectal varices Superior rectal ↔ middle and
inferior rectal
Varices of gut, butt, and caput (medusae) are commonly seen with portal hypertension.
Treatment with a transjugular intrahepatic portosystemic shunt (TIPS) between the portal vein
and hepatic vein relieves portal hypertension by shunting blood to the systemic circulation,
bypassing the liver. TIPS can precipitate hepatic encephalopathy due to  clearance of ammonia
from shunting.

FAS1_2019_09-Gastrointestinal.indd 365 11/7/19 4:42 PM