|
Cholelithiasis is
defined as the presence of stones within the lumen of the gall bladder
or in the extrahepatic biliary tree.
Gallstones vary
in composition. Sometimes they consist entirely of cholesterol, or
of calcium bilirubinate.
More often they are composed of alternating
layers of cholesterol, calcium bilirubinate, or cholesterol and
calcium carbonate and phosphate.
Protein is another
constituent.
Mixed cholesterol stones
are the commonest.
Pure cholesterol stones
are unusual and pigment stones account for approximately 20% but are
much more common in Asian countries.
Black and brown pigment
stones exist.
Black pigment stones are
more usually associated with hematological disorders and brown ones
are formed in association with infection.
Pigment stones are always
associated with crumbly stone debris.
In cholelithiasis the gall bladder may show any
number of changes, it may be normal or have mild hypertrophy of the
muscle coat with some loss of mucosa and variable chronic inflammation
is seen.
Biliary fistulas may lead to gall stone ileus if the fistula is duodenal.
Clinical course of gallstones:
Gallstones may
remain "silent" in the gallbladder for many years, and few patients
ever die of cholelithiasis itself.
One study that
followed patients with initially asymptomatic gallstones for upto 11
years found that half remained asymptomatic, one-third developed
significant symptomatology, and fewer than 20% developed serious
complications.
The incidence of
severe complications rose with increasing age.
Some studies
indicate that the 15-year cumulative probability that asymptomatic
stones will lead to biliary pain or other complications is less than
20%.
These statistics bear upon the question of whether to perform cholecystectomy for asymptomatic gallstones.
In some
otherwise healthy individuals, the small risk associated with cholecystectomy
may justify elective surgery.
However, when diseases
that increase the operative risk, such as cardiac or pulmonary
disorders, are present there is little reason not to manage "silent"
gall stones conservatively.
On the other
hand, more cautious physicians recommended that all asymptomatic
patients be treated medically unless symptoms supervene.
Diabetics present
a special case, because acute cholecystitis in these patients carries
a high risk of serious complications, and cholecystectomy during the
acute disease is far more dangerous than elective surgery.
Medical
treatment of gallstones has now become a possibility. Oral intake
of a bile acid, chenodeoxycholic acid or taurocholic
acid , and percutaneous instillation of cholesterol solvent into
the gallbladder have dissolved radiologically documented gallstones.
Lithotripsy has also been used.
Most of the
complications of cholelithiasis relate to the obstruction of the
cystic duct or common bile duct by stones.
Passage of stone
into cystic duct often, but not invariably, cause severe biliary colic
and may lead to acute cholecystitis.
Repeated episodes
of acute cholecystitis may lead to chronic cholecystitis.
The latter
condition can also result from the presence of stones alone.
Gallstones may
pass into the common bile duct (choledocholithiasis), where they lead
to obstructive jaundice, cholangitis, and pancreatitis.
In populations
where alcoholism is not a factor, gallstones are the most common cause
of acute pancreatitis.
Passage of a
large gallstone into the small intestine may cause intestinal
obstruction, a condition called gallstone ileus.
In obstruction of
the cystic duct, with or without acute cholecystitis, the bile in the
gallbladder is reabsorbed, to be replaced by a clear mucinous fluid
secreted by the gallbladder epithelium.
The term hydrops of the gall
bladder (mucocele) is applied to the distended and palpable
gallbladder, which may become secondarily infected.
Visit:
Cholesterol stone : click here
;Pigment stones (calcium bilirubinate);
"Mixed" stones
|
