750
U N I T 8
Gastrointestinal and Hepatobiliary Function
extent that endocrine and exocrine pancreatic functions
become deficient. At this point, signs of diabetes mellitus
and the malabsorption syndrome (e.g., weight loss, fatty
stools [steatorrhea]) become apparent.
Treatment consists of measures to treat coexist-
ing biliary tract disease. A low-fat diet usually is pre-
scribed. The signs of malabsorption may be treated
with pancreatic enzymes. When diabetes is present, it
is treated with insulin. Alcohol is forbidden because
it frequently precipitates attacks. Because of the fre-
quent episodes of pain, narcotic addiction is a potential
problem in persons with chronic pancreatitis. Surgical
intervention sometimes is needed to relieve the pain
and usually focuses on relieving any obstruction that
may be present.
Cancer of the Pancreas
Pancreatic cancer is now the fourth leading cause of
death from cancer in the United States, preceded only
by lung, colon, and breast cancer.
47,48
Considered to be
one of the most deadly malignancies, pancreatic cancer
is associated with a 5-year survival rate of only 4% to
6%.
47,48,54,55
The incidence of pancreatic cancer seems to
be increasing in all countries studied and has tripled in
the United States over the past 50 years.
48
The cause of pancreatic cancer is unknown. Age is a
major risk factor. Pancreatic cancer rarely occurs in per-
sons younger than 50 years of age, and the risk increases
with age. The most significant and reproducible environ-
mental risk factor is cigarette smoking, which doubles
the risk.
47,48,54–56
Diabetes and chronic pancreatitis also
are associated with pancreatic cancer, although neither
the nature nor the sequence of the possible cause-and-
effect relation has been established. There has been a
recent focus on the molecular genetics of pancreatic
cancer.
Clinical Manifestations.
Almost all pancreatic can-
cers are adenocarcinomas of the ductal epithelium, and
symptoms are primarily caused by mass effect rather
than disruption of exocrine or endocrine function. The
clinical manifestations depend on the size and location
of the tumor as well as its metastasis.
54–56
Pain, jaundice,
and weight loss constitute the classic presentation of the
disease. The most common pain is a dull epigastric pain
often accompanied by back pain, often worse in the
supine position, and relieved by sitting forward. Patients
may also present with diabetes or impaired glucose tol-
erance. Because of the proximity of the pancreas to the
common duct and the hepatopancreatic ampulla, cancer
of the head of the pancreas tends to obstruct bile flow.
Jaundice frequently is the presenting symptom of a per-
son with cancer of the head of the pancreas, and it usu-
ally is accompanied by complaints of pain and pruritus.
Cancer of the body of the pancreas usually impinges on
the celiac ganglion, causing pain. The pain usually wors-
ens with ingestion of food or assumption of the supine
position. Cancer of the tail of the pancreas usually has
metastasized before symptoms appear.
Migratory thrombophlebitis (deep vein thrombo-
sis) develops in about 10% of persons with pancreatic
cancer, particularly when the tumor involves the body
or tail of the pancreas. Thrombi develop in multiple
veins, including the deep veins of the legs, the subcla-
vian vein, the inferior and superior mesentery veins,
and even the vena cava. It is not uncommon for the
migratory thrombophlebitis to provide the first evi-
dence of pancreatic cancer, although it may present in
other cancers as well. The mechanism responsible for
the hypercoagulable state is largely unclear, but may
relate to activation of clotting factors by proteases
released from the tumor cells.
48
Diagnosis and Treatment.
Patient history, physical
examination, and elevated serum bilirubin and alka-
line phosphate levels may suggest the presence of pan-
creatic cancer but are not diagnostic.
54–56
The serum
cancer antigen (CA) 19–9, a Lewis blood group anti-
gen, may help confirm the diagnosis in symptomatic
patients and may help predict prognosis and recurrence
after resection. However, CA 19–9 lacks the sensitiv-
ity and specificity to effectively screen asymptomatic
patients.
56
Ultrasonography and CT scanning are the
most frequently used diagnostic methods to confirm
the disease. Intravenous and oral contrast–enhanced
spiral CT is the preferred method for imaging the pan-
creas. Percutaneous fine needle aspiration cytology of
the pancreas has been one of the major advances in
the diagnosis of pancreatic cancer. Unfortunately, the
smaller and more curable tumors are most likely to be
missed by this procedure. Endoscopic retrograde chol-
angiopancreatography may be used for evaluation of
persons with suspected pancreatic cancer and obstruc-
tive jaundice.
Most cancers of the pancreas have metastasized at
the time of diagnosis. Surgical resection of the tumor is
done when the tumor is localized or as a palliative mea-
sure. Radiation therapy may be useful when the disease
is localized but not resectable. The use of irradiation
and chemotherapy for pancreatic cancer continues to be
investigated. Pain control is one of the most important
aspects in the management of persons with end-stage
pancreatic cancer.
SUMMARY CONCEPTS
■■
The biliary tract, which consists of the bile ducts
and gallbladder, serves as a passageway for the
delivery of bile from the liver to the intestine.
■■
The most common causes of biliary tract disease
are cholelithiasis and cholecystitis.Three factors
contribute to the development of cholelithiasis:
abnormalities in the composition of bile, stasis
of bile, and inflammation of the gallbladder.
Cholelithiasis, in turn, predisposes to obstruction
of bile flow, causing biliary colic and acute or
chronic cholecystitis.
