Notes from the Video

What You're Going to Learn from This Video on Gallstones

As a surgeon I often find myself in clinic with a patient presenting with abdominal pain and an ultrasound demonstrating gallstones.

When I was a medical student I asked..."Why do these rocks form?"

In this video I'm going to give you the answer!

Here are the things we're going to be confident about with today's video:

1.  How common are gallstones?

2.  Why do gallstones form?

3.  What are the different types of gallstones?

4.  What are risk factors for getting gallstones?

5.  How can someone decrease their risk of getting gallstones?

How common are gallstones?

In the United States alone there are 25 million people with gallstones, 10-15% of the population, and this number is on the rise!

Gallstones are something that we see in the emergency room or in the clinic every day and especially in pediatrics, I'm seeing 10 times as much gallstone disease in children as I did in my training 10 years ago.

Why are gallstones bad?

Often they are not, often they are just sitting there in the asymptomatic patient just hanging out.

But they can cause complications.

If they are symptomatic from intermittent obstruction of the cystic duct a patient may come to clinic with right upper quadrant pain that is dull and crampy, radiating to the right side or back, intermittent and lasting for 15 minutes to an hour, aggravating by eating fatty food, received with rest and associated with nausea, vomiting and possible jaundice.

Remember how I take abdominal pain histories?  SRN OPD SARA!

Remember, this story is for a patient with symptomatic gallstones without complications.

Complications can happen!

If that gallbladder and bile become infected the intermittent crampy abdominal pain radiating to that right side may become constant abdominal pain with fever because now they have an infection related to their gallstones.

it's important to remember the anatomic relationships to the gallbladder when we are thinking of patients and clinical presentations. 

The gallbladder empties by the cystic duct which connects to the common hepatic duct and common bile duct to connect with the pancreatic duct and finally emptying in the duodenum.

A gallstone can cause a problem anywhere in this tree.

It may travel out of the cystic duct and obstruct the common bile duct, obstructing the biliary tree (choledocholithiasis) which can lead to jaundice and possibly ascending cholangitis.

The gallstone can travel even further and obstruct the pancreatic duct causing gallstone pancreatitis.

A gallstone may even create a fistula between the gallbladder or bile duct and the duodenum leading to a gallstone ileus where the gallstone is causing a bowel obstruction.

What are gallstones?

Gallstones develop when a particular substance gets super saturated and exceeds its ability to be soluble in bile.

Okay that's why we get gallstones, whether it's a cholesterol stone or a bilirubin stone or a calcium bilirubinate stone.

First, let's start out with cholesterol stones, why do we get cholesterol stones?

To begin to understand any of the types of gallstones we met ask our question..."What is bile?"

In bile we have bile salts, phospholipids, the most common being phosphatidylcholine, cholesterol, bilirubin that gives it that green color, water, electrolytes, vitamins and other nutrients.

What is a bile salt? 

We also call these bile acids and they assist with digesting and absorbing fats.   

How do we get a bile acid? Bile acids come from cholesterol and if we look at the generation of bile acids all of this happens within the liver to create primary bile acids and secondary bile acids.

Primary bile acids form after cholesterol transports into the liver and gets hydrolyzed, adding a bunch of hydroxyl groups or OH groups and that creates a hydrophilic component to that bile acid  so that it can digest fats. 

Remember, cholesterol itself is hydrophobic, "water fearing" or "water avoiding".

Hydrophilic is "water loving".

By hydroxylating cholesterol we form a primary bile acid and those primary bile acids are Colic and Chenodeoxycolic acid.

We also have secondary bile acids which assist digestion and absorption of fats. 

These form when the primary bile acid is conjugated or combined with either glycine or taurine to form glycocolic acid or torocolic acid. 

How do we resupply bile acids?

Remember, primary bile acids are essential for dissolving and digesting and absorbing fat as well as digestion and absorption of fat soluble vitamins (ADEK) and our body has the ability to resupply these bile acids after they are used. 

Primary and secondary bile acids reabsorb bile acids are resorbed in the terminal ileum and that is called enterohepatic circulation.

They can also be created de novo by the hydroxylation of cholesterol (primary) or conjugation with amino acids (secondary).

How about phospholipids?

What is a phospholipid?  A phospholipid is a glycerol backbone with two fatty acids and then the next carbon is connected with a phosphate as well as a small organic molecule. 

The most common phospholipid that we see in bile is phosphatidylcholine, also called lecithin. 

What is the purpose of a phospholipid?  Like bile acids a phospholipid has that hydrophobic tail but it has that hydrophilic head so it can help form micelles and those micelles help digest fat by breaking it down. 

Phosphplipids also help in cell membranes,  are anti-inflammatory, can be taken as a supplement to improve the digestion and absorption of fat, lower cholesterol and reduce inflammation. 

Phophatidylcholine can protect the liver, especially in alcoholic liver disease and it can also decrease the risk of gallstones.

Egg yolks, sunflower seeds, soybeans, even peanut butter is high in phosphatidylcholine and lecithin!  Adding some of those foods in your diet or in your patient's diet can help balance and create that positive ratio so that we can have a good fat digestion and absorption.

Finally, how about cholesterol?

Cholesterol is a waxy fat like substance  found in all cells in the cell membrane,  It's important for the production of hormones, the production of vitamin D and other substances and in the liver remember it's important in the formation of bile acids. 

How does cholesterol get in the bile?  Cholesterol gets in bile from bile acid production and diets that are high in fat and high in cholesterol producing a higher proportion of cholesterol in bile where it can gets super saturated and form gallstones.

Why is all of this important?  It's important because of the solubility triangle!

If you look at the solubility triangle in the video, the blue area is where the bile is in solution and there are no crystals and no stones, we have a perfect amount and balance of cholesterol bile salts or bile acids and phospholipids such as phosphatidylcholine.

When that triangle gets out of balance so we have too much cholesterol or not enough bile acids or not enough phospholipids, substances can crystallize.

What are some of the risk factors in getting cholesterol stones?

• Stasis of bile, when the gallbladder is not contracting
• Rapid weight loss, we see that in bariatric surgery
• Pregnancy, women who are pregnant have a higher risk of getting gallstones due to bile stasis
• Obese patients
• Genetic hypercholesterolemias

If we eat a healthy balanced diet, we drink plenty of water, we get to a healthy weight, we lose that excess weight, we stay away and avoid fatty foods or foods that are high in saturated fats and cholesterol and we get exercise we can decrease the risk of gallstone formation by maintaining a balance in that solubility triangle.

What are pigmented stones?

Pigmented stones are formed from cholesterol and pigmented with bilirubin or calcium bilirubinate.

We need to understand bilirubin to understand pigmented stones!

Bilirubin comes from the breakdown of hemoglobin and if we see pigmented stones we need to be thinking about situations with increased hemoglobin breakdown like increased RBC or red blood cell turnover and hemolysis.  This generates increased bilirubin in the bile that pigments cholesterol stones.

They are more commonly symptomatic because they are small and can travel out of the cystic duct causing either acute cholecystitis by getting stuck in the cystic duct or traveling down causing an obstruction with jaundice with choledocolithiasis or of course obstructing the pancreatic duct and leading to acute gallstone pancreatitis.

Within pigmented stones there are black stones and brown stones.

Both are primarily composed of cholesterol, brown stones are usually 70-80% cholesterol while black stones have a higher concentration at 90-95%.

Brown stones get their color from a higher concentration of bilirubin while black stones are formed from calcium bilirubinate, formed from the breakdown of bilirubin.

Brown stones are more common with high cholesterol, obesity and medical conditions like diabetes while black stones are associated with chronic biliary issues like cholangitis or cirrhosis.