Bile duct pressure

Digestive system g agonists decrease secretion of stomach acid, reduce gastric motility, and prolong gastric emptying. Pancreatic, biliary, and intestinal secretions are reduced. Intestinal transit is also slowed. Peristaltic movements are reduced, but tone is increased, sometimes causing spasm. As a result, constipation is a frequent problem with opioid use. Bile duct pressure is also increased by opioids. 

The gastrointestinal tract is the only system outside the central nervous system (CNS) with significant concentrations of opioid receptors. This reflects their common embryonic origins. Opioids increase intestinal tone and decrease propulsive peristalsis, resulting in delayed gastric emptying and constipation or ileus. Opioids increase common bile duct pressure and decrease bile production and flow, primarily because of spasm of the sphincter of Oddi. The tone of the bile duct itself is also increased. 

Butsch JL, Okoli JA. The effect of nalbuphine on the common bile duct pressure. Am Surg 1988 54(5) 253-5. 

Morphine can reduce biliary secretions, and patients with biliary colic may experience an exacerbation of pain after morphine. Similarly, opioids such as morphine can cause bile duct spasm [27]. Opioid-induced spasm of the sphincter of Oddi and increased intrabiliary pressure may result in a secondary increase in LFTs [55]. 

Acute cholangitis Thickened bile-duct walls with inflammatory infiltration as well as focal ulcerations are found histologically. The portal fields are expanded by oedema and reveal pericholangiolar and intracholangiolar infiltrations from leucocytes. Ductal tortuosity reflects increased pressure in the biliary ducts. Periductular abscesses can develop during the course of cholangitis, (s. fig. 32.2)... 

This condition is probably a variant of polycystic liver disease. Aberrant bile ducts and blood vessels are noticeable in the fibrous cyst capsule. The cyst fluid is clear or brownish due to altered blood. Usually, the cyst develops in the inferior-anterior segment of the right lobe. The symptoms, which depend on the size of the cyst, include pressure effects on adjacent organs, cholestasis and obstructive jaundice. 

In NRH, the liver is interspersed with numerous diffuse nodes, which are 1-3 mm in size (occasionally up to 3 cm) and yellow to yellowish brown in colour with blurred boundaries they consist of hyperplastic hepato-cytes. No fibroses or perinodal connective tissue septa are evident. The multilayered, disordered trabeculae do not have a lobular structure. (66, 69) CD 8" cytotoxic T cells infiltrate the acinus. The nodes lack central veins and bile duct proliferations. The intemodular parenchyma becomes atrophied due to pressure. It is possible by means of reticulin staining to demonstrate the nodes with the irregular trabeculae, whereas the altered vessels are best shown using elastica staining. The liver surface is smooth. (78) In the course of disease, presinusoidal, and later sinusoidal, portal hypertension with hepato-splenomegaly and oesophageal varices are usually observed. (64, 65, 67) (s. fig. 36.4)... 

Therapeutic doses of opioids constrict the sphincter of Oddi, and biliary tract pressure rises ten-fold. Patients with biliary colic can have exacerbation of pain after morphine. Likewise, opioids such as fentanyl, morphine, and dextropropoxjrphene can cause bile duct spasm (SEDA-21, 85). 

Inhibition of cholesterol biosynthesis occurred in the small intestine of rats after administration of D-limonene for 7 days, but no significant effect on the secretion of radiolabeled cholesterol into bile and feces was observed. o-Limonene increased the perfusion pressure of the sphincter of Oddi in dogs when injected IV or directly into the common bile duct. 

The intestine is isolated and perfused via the mesenteric artery with oxygenated perfusate, preferably, heparinized blood at 37°C and at a physiological pressure and blood flow. Venous blood from the portal vein is either collected first pass or returned to the reservoir for reoxygenation and recirculation. The effect of bile on absorption from the gut can be assessed by the infusion of bile via an indwelling cannula that is inserted into the bile duct in the direction of the gut. 

Atropine exerts a mild antispasmodic action on the gallbladder and bile ducts, an effect that usually is insufficient to overcome or prevent the marked spasm and increase in biliary duct pressure induced by opioids, for which nitrites (see Chapter 31) are more effective. 

BILIARY TRACT After the subcutaneous injection of 10 mg morphine sulfate, the sphincter of Oddi constricts, and the pressure in the common bile duct may rise more than tenfold within 15 minutes this effect may persist for 2 hours or more. Fluid pressure also may increase in the gallbladder, producing symptoms that vary from epigastric distress to typical biliary cohc. All opioids can cause biliary spasm. Atropine only partially prevents morphine-induced biliary spasm, but opioid antagonists prevent or relieve it. Nitroglycerin (0.6-1.2 mg) administered sublingually also decreases the elevated intrabiliary pressure. 

Cholangitis occurs in the presence of partial or complete obstruction of the common bile duct (CBD), with increased intraluminal pressures, bacterial infection of the bile with multiplication of the organisms within the duct, and seeding of the bloodstream with bacteria or endotoxin. Cholangitis can rapidly become a life-threatening condition. 

Tremblay et al. (60 ) measured the effect of fentanyl on the pressure in the bile ducts, and found a significant elevation of the passage pressure. 

Cholecystokinin relaxes the sphincter of Oddi and contracts the gallbladder, and as a result bile is secreted in the intestine. When the sphincter closes again, the bile flows into the duct and refluxes into the cystic duct and the gallbladder. The pressure of bile in the gallbladder is usually the same as or slightly lower than that in the duct because the gallbladder simultaneously relaxes and withdraws water from the bile as it is contained in the reservoir. 

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