Gallstones — From Formation to Detection

Published in

GirlsGetMAGIC

8 min readAug 26, 2023

Authors: Sheen Raina, Dr. Sukhbir Kaur

Please note: “This article is for educational purposes and should not be used for diagnosis purposes. Please consult a doctor for proper medical consultation to treat gallstones.”’

I. Introduction

The gallbladder is a small pear-shaped organ that is part of the digestive system. It measures about 3 to 4 inches, is located underneath the liver’s right lobe, and is connected to the liver and small intestine through a network of ducts (See Fig. 1). The primary function of gallbladder is storing and concentrating bile produced by the liver. This bile is released into the small intestine and aids in fat digestion. Nonetheless, gallstones can develop in the gallbladder, which are solidified deposits of cholesterol, bilirubin, or calcium bilirubinate. Gallstones can lead to blockages and pose significant health risks. This condition, also referred to as cholelithiasis, affects about 10–15% of the US population, 6% men and 9% women (Stinton et al., 2010). Annually, approximately a million people receive a gallstone diagnosis, and a quarter of them require surgical intervention (Triantafyllou & Skipworth, 2023). While not always symptomatic, they can cause severe pain when they are. Gallstone formation is a common occurrence given that multiple factors can exacerbate the condition.

Figure 1: Anatomy and location of gallbladder in the human body (Image created in BioRender)

II. Causation Factors

A. Diet and Energy Intake

Diets characterized by high caloric intake, low fiber content, and excessive refined sugars could lead to increased susceptibility to gallstones. Carbohydrates, particularly refined sugars, increase insulin secretion, which eventually drives cholesterol synthesis in the liver, heightening the risk of gallstone formation (See Fig. 2). Carbohydrates may also induce changes in lipoprotein metabolism that bring about modifications in the bile composition (Triantafyllou & Skipworth, 2023). In contrast, intake of insoluble fiber is inversely related with gallstones.

One study in North Indians and Caucasians showed that a hypercaloric diet correlates with a higher prevalence of gallstones (Cuevas et al., 2004). However, other studies show a negative association between energy intake and the risk of gallstones in men (Attili et al., 1998). Additional factors that can increase the risk of gallstone formation are vitamin C deficiency, coffee consumption, and sapogenins from legumes and lentils (Stokes et al., 2011).

Figure 2: Risk factors for gallstone formation (Image created in BioRender)

B. Gender

Women are more likely to develop gallstones than men because of pregnancy and sex hormones. The hormone estrogen increases biliary cholesterol secretion, affecting the amount cholesterol in bile, and causing cholesterol supersaturation of bile. Progesterone slows the emptying of the gallbladder, thus storing the bile for longer and contributing to concentration of bile components. Hormone replacement therapy and birth control pills also increase the risk of gallstones (Stinton et al., 2010).

C. Genetics and secondary health risks

Age and genetics are significant contributors to gallstones. This is evident in the Indian population, as their genes elevate the amount of cholesterol in bile (Grünhage & Lammert, 2006). Indians have the highest diagnosis of gallstones in the US. Current research is focused on whole-genome association studies and refined haplotype mapping in gallstone patients to identify common lithogenic genes (Gurusamy & Davidson, 2014). Lithogenicity refers to the capacity of a substance, condition, or genetic factor to promote the formation of crystalline structures within a bodily system. Lithogenicity and gallbladder dysfunction is the leading cause of gallstones in elderly male population. Folks undergoing weight loss surgery, and health conditions such as sickle cell anemia or alcoholism-led liver cirrhosis are also more susceptible to gallstones (Stokes et al., 2011).

III. Types of Gallstones

There are four main types of gallstones: cholesterol stones, mixed stones, combination stones, and pigment stones (See Fig. 3).

If cholesterol makes more than 70% of the stone’s dry weight, it is classified as a cholesterol stone, is usually white to yellow colored, and has an oval to round shape, although a mulberry shape is more common. On the contrary, pigment stones contain 40% to 60% calcium bilirubinate and only 25% to 30% cholesterol, are mostly black in color, and small to spherical in shape. Cholesterol stones are more common than pigment stones (Kim et al., 2003).

When both bile pigments and cholesterol are present, the stone is termed as a mixed stone or a combination stone. Mixed stones form when bile and cholesterol are mixed without defined layers, they can have various shapes, and exhibit colors ranging from yellowish white, yellowish brown, greenish brown, to blackish brown. They have concentric and radial cross sections. Combination stones, however, are the only type of gallstones with distinct layers. One layer is made of bile pigments, and the other of cholesterol, with the inner layer having circular cross sections. These stones are oval or round, and typically brownish or dark brown in color (Kim et al., 2003; Qiao et al., 2013).

Figure 3: Different types of gallstones (Image created in BioRender)

IV. Symptoms

Gallstones are more common than many people realize. Small gallstones, which often go unnoticed and don’t cause significant issues, are classified as asymptomatic gallstones. The term “gallstone disease” or cholelithiasis is used when gallstones become problematic and lead to symptoms.

A major symptom of gallstones is ‘biliary colic’ — A steady pain in the upper right abdomen that arises due to gallstone obstruction. Additionally, epigastric pain and intolerance to fatty or fried foods, causing nausea, bloating, flatulence, and frothy or foul-smelling stools, is a common occurrence (Gurusamy & Davidson, 2014).

Rare complications of gallstones include acute cholecystitis (inflammation of gallbladder), acute cholangitis (inflammation of bile duct system), acute pancreatitis (inflammation of the pancreas), intestinal obstruction, and obstructive jaundice. Both acute cholangitis and acute pancreatitis are life-threatening, with a 24% mortality rate and a 3–20% mortality rate respectively (Triantafyllou & Skipworth, 2023).

V. Gallstone Diagnosis

An ultrasonography is the primary method of diagnosing gallstones, especially when signs of inflammation are present. It has 90% sensitivity and 88% specificity, and can detect the size of the gallstone as well as the organs around it. An ultrasonography can detect gallstones as small as 1.5 to 2 mm, but the sensitivity decreases for smaller stones (Gurusamy & Davidson, 2014).

Abdominal computed tomography (ACT) is another method of detecting gallstones. However, it is less sensitive than an ultrasonography. Gallstones have similar radiolucency as bile, so they can be hard to distinguish. But higher calcium content provides more contrast and visibility. ACT has a diagnostic sensitivity of 80% and cannot detect gallstones less than 5mm (Chung, 2023). But it is valuable for visualizing secondary complications such as the dilatation of common bile duct, acute cholecystitis, and biliary pancreatitis.

A less common diagnostic approach involves using ERCP (endoscopic retrograde cholangiopancreatography) or MRCP (magnetic resonance cholangiopancreatography). In ERCP, an endoscope is inserted through the mouth to the small intestine to locate gallstones. Conversely, MRCP is a specialized MRI focused on the biliary and pancreatic system, allowing visualization of gallstones (Portincasa et al., 2016).

VI. Treatment Options for Gallstones

If the gallstones are small and not critical, they can be treated with prescribed medication like Actigall or Chenix, which contain bile acids to help dissolve the gallstones. However, medications require a few months to years to dissolve all of them (Portincasa et al., 2016). For larger gallstones causing serious complications, a more aggressive approach is needed.

Cholecystectomy, the surgical removal of gallbladder, is the preferred method of treatment regardless of the stone type — be it cholesterol, pigment, or mixed stone (See Fig. 4). The procedure is relatively safe and has a mortality rate of 0-0.3% (Beckingham, 2023). Laparoscopic cholecystectomy, a procedure performed by a key-hole operation with laparoscopic exploration has a shorter hospital stay, decreased pain, earlier return to work, and better cosmesis. The procedure, often completed within a day, involves incisions smaller than 1 cm each. Since developing a fat intolerance is possible after the surgery, a low-fat diet is usually recommended. Second option is an open cholecystectomy, where there is open exploration of the common bile duct.

Figure 4: Surgical removal of the gallbladder (Image created in BioRender)

If surgery is not possible, then shock wave lithotripsy is necessary. This treatment is possible for most people, if the gallbladder is functioning normally, and the stones are small. This is when shock waves are precisely targeted at a gallstone, causing it to break up and fragment (Gurusamy & Davidson, 2014).

VII. Conclusion

The gallbladder, a crucial organ in the digestive system that serves a vital function of breaking down fats. Change in the chemical composition of bile triggers gallstone formation, which is further exacerbated by diet, age, gender, and secondary health risks. Recognizing the symptoms of gallstones, researching the causation factors, and a timely diagnosis are crucial factors in alleviating the disease progression. By addressing these factors comprehensively, individuals can maintain their gallbladder health and overall well-being.

I would like to thank Dr. Namrata GR Raut, Dr. Ira Pramanick, and Dr. Pi-Chuan Chang for their help with this article.

VIII. References

Gallstones — From Formation to Detection

Written by Sukhbir Kaur