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Gallstones, types, causes, symptoms, and complications

Gallstone formation is a common health problem that involves the formation of stones in your gallbladder or your common bile duct. In this article, we provide you with simple, accurate information about your biliary system, and gallstone types, causes, symptoms, and complications.

Biliary system | Gallstones | Types of gallstones | Causes | Symptoms | Complications |Summary

Biliary system:

  • The biliary system is part of your digestive system. It consists of organs and ducts all conceded and serve to store and transport the bile into your intestine.
  • This system consists of gallbladder and bile ducts.
  • The main function of the biliary system is to store and transfer bile from the liver into your intestine

Bile passway (Ref):

  • The bile is secreted by liver cells and flows through the right and left hepatic ducts.
  • Both the right and left hepatic ducts drain their content in the common hepatic duct.
  • The common hepatic duct joins with a duct connected to the gallbladder called the cystic duct and forms the common bile duct.
  • The common bile duct enters your small intestine a few inches below the stomach.
  • About 50 % of bile secreted between meals flows directly through the common bile duct into the small intestine The other half of bile is stored in your gallbladder. When you take your meal, your gallbladder is contracted and releases the stored bile secretion to help in the digestion process.
  • In case of gallbladder removal, the secreted bile from the liver pass directly from the liver into the small intestine.

What are the main components of bile?

  • Bile is a greenish-yellow thick steaky fluid stored in your gallbladder (a pear-shaped organ located below your liver).
  • Bile is composed mainly of bile salts, pigments, lipids, cholesterol, and electrolytes.
  • Bile salts:
    • Bile salts help in the digestion of fats, cholesterol, and fat-soluble vitamins and facilitate their absorption from the intestine.
  • Bile pigments:
    • Bilirubin is the main bile pigement. It results from the degradation of hemoglobin of old damaged red blood cells.

What are the main functions of the bile?

  1. Aid in the digestion process
  2. Remove waste products mainly hemoglobin and excess cholesterol from your body.


What are gallstones?

  • Gallstones are solid masses in your gallbladder or/and bile ducts.
  • They are formed when there is an imbalance in the composition of bile resulting in precipitation of one or more of its components. This led to three types of gallstones as follows.

Epidemiology of gallstones:

  • In the USA, the prevalence of gallstones is about 10% to 15% of the adult population.
  • Approximately 6% of men and up to 9% of women have gallstones worldwide (Ref).
  • In 2004, the annual healthcare cost of gallstones was $6.2 billion (Ref)
  • It is reported that in each ear more than 50,000 cholecystectomies (gallbladder removal) are performed in the UK, also, about 700,000 are performed in the USA (Ref).
  •  More than  80% of patients having gallstones remain unaware of their disease and about 1% to 2% of patients per year develop complications due to unawareness and need surgery as treatment (Ref).

Types of gallstones

1. Biochemical classification of stones:

Types of gallstones according to their biochemical composition:

  1. Cholesterol gallstones:
  • It is known as cholesterol-rich gallstones. 
  • represent about 37% to 86% of gallstones. 
  • This type of gallstone is common in  Europe and North America.
  • It results from increased secretion of cholesterol, decreased gallbladder motility
  1. Pigmented gallstones:
  • Represent 2-27% of gallstones.
  • May by black pigment gallstones or brown pigment gallstones
  • This type of gallstone is commonly associated with gallbladder infection as a result of biliary obstruction (Ref).
  1. Mixed gallstones:
  • About 4-16 % of gallstones are mixed gallstones (cholesterol and pigment gallstones)

2. Anatomical classification of stones:

Types of stones according to their location (anatomical classification of gallstones):

  1. Cholelithiasis: 
  • it means the formation of stones within your gallbladder.
  • About 88-94% of patients suffering from gallstones have stones in the gallbladder.
  • Cholelithiasis could be cholesterol or pigmented (black or brown) gallstones.

2. Choledocholithiasis:

  • It means the stones are located in the common bile duct. 
  • About 6-12% of patients suffering from gallstones have stones in the common bile duct. 

Causes of gallstones:

  • Decrease gallbladder motility
  • Cholesterol supersaturation
  • Decrease bile salts levels.

Risk factors of gallstone formation:

  • Age (risk increases with age)
  • Family history
  • Oral contraceptive
  • Gender (female higher than male).
  • Pregnancy
  • Obesity
  • Diabetes Mellitus
  • Liver diseases (liver cirrhosis)
  • Rapid weight loss.
  • Long time fasting

Symptoms of gallstones:

  • The majority of patients with gallstones have no symptoms (Asymptomatic gallstones).
  • Those with symptoms commonly suffer from upper gastrointestinal problems mainly upper abdominal pain.

Symptoms of gallstones include:

  • Biliary colic:
  • The biliary colic occurs when gallstones block the outflow of the gallbladder. The pain is triggered by gallbladder contraction against a closed orifice.
  • Biliary colic is experienced in about 20 % of patients with gallstones (Ref).
  • The pain occurs mainly in the right upper quadrant and often radiates to the right shoulder.
  • Moreover, the pain is a sudden, and sharp pain that subsides within hours when the stone is fall back in the gallbladder or passes into the common bile duct.
  • Obstructive jaundice:
  • Jaundice is a medical condition that means your serum bilirubin concentration exceeds 50 μmol/liter.
  • Having gallstones represent one of the most common causes of jaundice.
  •  Other symptoms include:
  • Clay-colored stools
  • Fatty food intolerance
  • Chills
  • Nausea 
  • Vomiting 
  • General weakness
  • Loss of weight 

The complications of gallstones:

  • Gall bladder perforation 
  • Bile duct obstruction
  • Pancreatitis 
  • Gallbladder cancer.
  • Gallbladder infection:
    • It is medically known as Empyema of the gallbladder.
    • It is an acute infection of the gallbladder wall and could lead to severe complications.
  • Gangrenous gallbladder:
    • It is a rare but serious case that could result from gallstones.
    • It results from gallbladder destination, increased gallbladder tension and pressure of the gallbladder wall, and consequently decreased blood supply to the gallbladder leading to necrosis and gallbladder gangrene.  


  • Gallstone formation is a common gastrointestinal disease that involves the formation of stones in your gallbladder or your common bile duct.
  • According to the biochemical composition, gallstones are classified into cholesterol gallstones and pigmented gallstones (black and brown pigmented gallstones).
  • The majority of patients with gallstones have no symptoms, while those with symptoms commonly suffer from sudden, sharp upper abdominal pain.
  • Gallstones may lead to complications including, pancreatitis, bile duct obstruction, jaundice, gallbladder cancer, and rare complications such as gallbladder gangrene

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