This is a handwritten lecture discussing Gallstone for medical students studying for the USMLE boards.
0:00 Anatomy of Gallbladder
1:52 Formation of the Gallstone
2:30 Types of Gallstones
6:08 Causes of Gallstones
10:38 Symptoms of Gallstones
15:31 Ultrasound
20:25 Treatment of Gallstones
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BONUS QUESTION: What risk does a porcelain GB pose and how does it occur?
GB adenocarcinoma from chronic cholecystitis
ANATOMY
We will start with the anatomy. First you have the gallbladder which holds the bile. It is connected to the cystic duct which combines with the hepatic duct to form the common bile duct. The pancreatic duct combines with common bile duct to secrete bile through the Sphincter of Oddi. Gallstones are typically obstructed in the cystic duct or common bile duct. These are common questions in the USMLE.
TYPES OF GALLSTONES
Bile in the gallbladder can form sludge and then form gallstones. There are three types of gallstone, cholesterol gallstones, black gallstones and brown gallstones. The most common form of gallstone is the cholesterol gallstone which forms a yellow stone. Approximately 85 percent of stones will be cholesterol. It is formed due to abnormal ratio between cholesterol and bile acids. As cholesterol can precipitate out to complex with calcium to form a gallstone. Also biliary stasis can lead to the development of gallstones. Black gallstones are formed due to breakdown of hemoglobin which increases production of bilirubin. This occurs during intravascular hemolysis such as sickle cell and hereditary spherocytosis. So in the USMLE if they mention a child with recurrent gallstones and anemia, you may want to consider hemolytic anemias. Brown gallstones are formed due to infection from E. Coli, Clonorchis Senensis and Ascaris Lumbricoides.
CAUSES OF CHOLESTEROL GALLSTONES
Biliary stasis causes are age, estrogen, female gender, pregnancy, contraceptives, fasting, TPN, spinal cord injury. Causes of elevated cholesterol include obesity, dyslipidemia, diabetes. Cause of low bile acid include cirrhosis, Crohn's Disease and ileal disease or resection. Any of these factors increase the risk of gallstones.
SYMPTOMS OF GALLSTONES
Biliary colic describes pain in the right upper quadrant radiating to right shoulder and back and lasts for 30 minutes to 6 hours. This occurs typically after a fatty meal causes contraction of the gallbladder and the gallstone lodges into cystic duct and pressure leads to pain. If non-complicated patient will not have any other symptoms such as fever, tachycardia and labs will be normal. However, complications, such as cholecystitis, cholangitis, pancreatitis, gallstone ileus may occur. However, here we are only focusing on uncomplicated gallstones.
WORKUP OF GALLSTONES FOR USMLE
The primary test of choice for patient suspected of having gallstones is RUQ Ultrasound. It can detect gallbladder sludge and gallstone. To differentiate a gallstone from polyp you can look for an acoustic shadow. If negative and there is high suspicion for gallstones, you can repeat the ultrasound and even due an endoscopic ultrasound which can detect smaller gallstones and rule out other causes such as peptic ulcer disease or gastritis. Keep in mind USMLE may ask you questions as to when this is indicated.
TREATMENT OF GALLSTONES FOR USMLE
First manage pain with NSAIDs, or opioids if there is contraindications. Emergency surgery is never indicated for patients with non-complicated gallstones. Elective surgery is the removal of the gallbladder with the gallstones. It depends on patient preference, but if they have porcelien gallbladder, adenoma, or gallstones greater then 3cm, then they should do the surgery regardless. Expectant management is for those who are no surgical candidates or preference. They need to be monitored for development of complicated gallstones. Some benefits noted with ursodeoxycholic acid. Upon discharge advise the patient to return if pain is greater then 4 hours as this increases the risk for complicated gallstones. Also USMLE wants you to know that you need to advise a diet with low saturated fats and slow weight loss.