5 Caring for the patient with a disorder of the liver, biliary tract and exocrine pancreas

ANATOMY AT A GLANCE

These closely associated structures are located in the upper abdominal cavity immediately below the diaphragm (Figure 5.1). The liver is a large organ weighing approximately 1.4 kg and is situated in the upper right portion of the abdomen. The gall bladder is much smaller (7–10 cm in length) and is located under the liver. Bile is passed from the liver to the gall bladder via the left and right hepatic ducts and subsequently into the duodenum via the bile duct. The pancreas lies across the upper abdomen being 12–15 cm long but only 2.5 cm thick. The head of the pancreas is located by the curve of the duodenum and the body and tail lie to the left of the head. Pancreatic secretions drain via the pancreatic duct into the duodenum. Normally, the pancreatic duct and bile duct enter the duodenum together as a common duct known as the ampulla of Vater.

Figure 5.1 The pancreas and associated anatomy.

PHYSIOLOGY YOU NEED TO KNOW

The liver has many vital functions and is metabolically extremely active. Key functions of the liver include:

• Formation of bilirubin from the haem of degraded old red blood cells which is then secreted into bile and passed to the duodenum to assist digestion of fats by emulsification of lipids.

• Synthesis of bile salts which also assist in digestion of fats.

• Processing of drugs and hormones.

• Phagocytosis of aged red and white blood cells plus some bacteria is carried out by Kupffer cells.

• Storage of vitamins such as A, B₁₂, D, E and K plus minerals such as iron.

• Maintenance of blood glucose levels by converting glucose to glycogen and triglycerides for storage when blood glucose levels are high. When blood glucose levels are low, stored glycogen is broken down into glucose and released into the bloodstream. Amino acids and lactose can also be converted to glucose.

• Protein metabolism. Amino acids have the amino group removed from them by liver cells so they can be used for adenosine triphosphate (ATP) production. ATP is a key energy source for body cells. This deamination forms ammonia which is converted into the less harmful substance urea which is excreted in urine.

• Lipid metabolism. This includes synthesizing cholesterol and using it to make bile salts and breaking down fatty acids to make ATP.

• Synthesis of the active form of vitamin D along with the skin and kidneys.

The gall bladder. The liver secretes up to 1 L per day of strongly alkaline bile. It is stored and concentrated by a factor of up to 10 in the gall bladder before excretion into the small intestine, particularly to help digest the fatty portion of a meal.

The exocrine pancreas constitutes 99% of this organ, the remaining 1% is the endocrine portion concerned with the secretion of hormones such as insulin and glucagon. The exocrine pancreas secretes pancreatic juice which contains a range of digestive enzymes needed in the small intestine. These include:

• Amylase to digest carbohydrate.

• Several protein-digesting enzymes such as the inactive enzyme tripsinogen which is converted to active tripsin when it encounters enterokinase within the small intestine.

• Lipase which digests triglycerides.

CIRRHOSIS OF THE LIVER (P509)

PATHOLOGY: Key facts

Chronic and diffuse degeneration of the liver associated with the formation of scar tissue characterizes cirrhosis. The liver becomes congested, function deteriorates and portal hypertension ensues. Portal hypertension is associated with the development of ascites – the accumulation of large quantities of fluid in the abdomen due to disruption of the normal balance of pressures in the capillary bed impairing the return of fluid to the venous capillaries. The most likely cause is alcohol abuse although many alcoholics do not develop cirrhosis. Cirrhotic changes can also occur after chronic hepatitis, obstruction of bile flow (e.g. due to gallstones) or in response to autoimmune processes.

MEDICAL MANAGEMENT

Liver function tests (LFT) measure the levels of key enzymes and are important in determining the severity of the disease in addition to the history and physical signs found upon examination. Interpretation of LFT results is complex, but elevated aminotransferases generally indicates liver cell damage. Blood tests are also important as an extended prothrombin time indicates clotting disorder. This is significant, as the liver synthesizes many of the blood coagulation factors.

Once the diagnosis is confirmed, alcohol intake must be eliminated, if that is the cause, to prevent further damage. There is no cure for cirrhosis although liver transplant may be offered if the person is willing to give up drinking. Medical management is usually symptomatic involving fluid restrictions and the cautious use of diuretics to reduce ascites. If the volume of ascites is interfering with respiration, paracentesis is performed using a sterile cannula to tap off the excess fluid from the peritoneal cavity.

PHARMACOLOGY FOCUS

There are no specific drug therapies that treat cirrhosis. Hepatic neurological disorder is caused by the failure of the liver to metabolize and detoxify nitrogenous substances, therefore part of the treatment involves reducing the levels of these substances in the body. As one of the main functions of the liver is to metabolize drugs and hormones, all medication should be carefully reviewed as normally therapeutic doses could quickly become toxic. Drugs which are normally inactivated in the liver such as paracetamol, diazepam, oral contraceptives and opiates are excluded.

PRIORITIES FOR NURSING CARE

Itching can be a major problem so apply anti-pruritic lotions and moisturisers, keep skin cool and change bedding daily. Assist with personal hygiene and keep nails short.

Assist with and encourage nutrition in accordance with dietician’s orders. Typically, this will involve a high-calorie (2500–3000 kcal/day) high-carbohydrate diet with vitamin supplements. Protein content may be limited or excluded completely depending upon the patient’s condition due to the toxic effects of accumulating nitrogenous waste substances which the liver is unable to metabolize.

Encourage upright position to assist breathing if ascites is a problem.

Assist with mobility and provide pressure area care.

The problem of alcohol intake will have to be discussed if this is thought to be the cause of the problem (p. 913). Box 5.1 reveals some key facts about alcohol intake, while Box 5.2 shows recommended daily intake limits. A useful tool which assesses whether a patient has an alcohol problem is shown in Box 5.3. If the patient answers yes to more than one of these questions, this indicates a likely problem. This can be used in primary care settings as well as in a hospital.