Gallstones are common. Occurring in approximately in 1/8th of the population. The majority are asymptomatic, but about 1-4% will become symptomatic. The presentation of gallstones can widely vary depending the section of the biliary system that is involved.
First let’s recap what bile is and how it forms:
Pathophysiology
Gallstones form due to supersaturation of bile. Depending on the composition of the bile the composition of bile may change. There are 3 main types of gallstones:
- Cholesterol stones - due to excess cholesterol production (correlated to obesity and poor diet).
- Pigment stones - due to excess bile pigments. Commonly seen in individuals who have increased Hb metabolism, as seen in haemolytic anaemia.
- Mixed stones - made up of both cholesterol and bile pigments.
The gallstone gets lodged in the neck of the gallbladder but no inflammatory response is elicited. The contraction of the bladder on the occluded neck is what causes the pain.
😷 Presentation
Sudden, dull, colicky pain in the RUQ which may radiate to the epigastric/back region.
The pain is worse postprandially, especially with fatty foods.
Nausea + vomiting.
15% of patients are found to have a stone in the CBD (choledocholithiasis) and this causes obstructive jaundice.
No fever is present in biliary colic (not always true).
The function of bile is to aid absorption of insoluble fats through emulsification.
Bile is made up of bile salts, phospholipids, conjugated bilirubin, cholesterol, bile pigments (which are products of Hb metabolism).
Bile is made in the liver, and stored in our gallbladder. The gallbladder is located between the right & quadrate lobes of the liver. It connects via the cystic duct to the common bile duct [CBD] (which is also joined by the common hepatic duct). The CBD then joins the pancreatic duct of the pancreas to form the Hepatopancreatic ampulla of Vater.
Cholecystokinin (CCK) is released from the duodenum when digesting food. It’s function is to cause the gallbladder to contract for the release of bile.
⚠️ Risk factors
Other risk factors include:
- Oral contraceptives - as oestrogen causes an increase in cholesterol (due to potentiated HMG-CoA reductase activity) as compared to bile
- Haemolytic anaemia - as this increases the proportion and sedimentation of bile pigment.
- Malabsorption - as seen in Crohn’s disease or a previous ileal resection.
An increase in fatty foods can cause release of CCK and this may cause nausea/vomiting + pain.
🔍 Investigations
🧰 Management
- Analgesia - paracetamol or NSAIDS or opiates (depending on the severity of the pain).
- Lifestyle advice - weight loss + exercise, low fat diet.
- 🔪 Laparoscopic cholecystectomy should be offered within the first 6 weeks of presentation.
