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Gallstones and Biliary Colic

by | 4 Feb, 2021

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Introduction

Gallstones (also known as cholelithiasis) are hardened remnants of bile that can form and collect in your gallbladder. Most gallstones are asymptomatic despite their high prevalence and are discovered incidentally. Symptomatic cases present following obstruction and/or inflammation of the biliary tract, including biliary colic, cholecystitis, ascending cholangitis and pancreatitis.

Epidemiology

Gallstones are common in adults and can affect between 5-25% of adults, especially women and older adults.

Basic anatomy

The gallbladder is a small sac located behind the liver and serves to store the bile that your liver produces continuously. 

Once chyme passes from the stomach into the duodenum, bile is squeezed out via the biliary tree and into the duodenum. Biles consists of water, cholesterol, bile acids, electrolytes, phospholipids and conjugated bilirubin. The primary purpose of bile is to facilitate digestion by providing optimal pH and emulsion for the enzymatic activity. Another use of bile is a means for the body to excrete bilirubin.

Risk factors

There are both modifiable and non-modifiable risk factors for developing gallstones.

Modifiable risk factorsNon-modifiable risk factors
1. Rapid weight loss
2. Obesity
3. Sedentary behaviour
4.Smoking
5. Total parenteral nutrition
6. Diet:

High calorie
– Low fibre
– Highly absorbable sugars

7. Medication:
– Oestrogen
– Octreotide
– Ceftriaxone

8.Medical conditions:
– Haemolytic conditions
– Hypertriglyceridaemia
– Cirrhosis
– Cystic fibrosis
– Ileal diseases
– Bacterial or parasitic infections
– Neoplasms
1. Older age
2. Female
3. Genetic factors/family history

A commonly used aide memoire for remembering the main risk factors for gallstones is ‘5 Fs’:

  • Female sex
  • Fair: Caucasian ethnicity
  • Fat: BMI >30
  • Fertile: had one or more children
  • Forty: age over 40 years

Pathophysiology

Gallstones form through three main pathways: cholesterol supersaturation, bilirubin excess and gallbladder motility/contractility defects.

Cholesterol supersaturation

When the liver produces more cholesterol than the bile can dissolve, the extra cholesterol will eventually precipitate as crystals. These crystals become trapped within the gallbladder and eventually accumulate and grow into gallstones.

Bilirubin excess

Excess excretion of bilirubin, a metabolic by-product of normal haem breakdown, may also cause stone formation. This is exacerbated by conditions that increase haem breakdown and its excretion into bile. The excess will eventually crystallize and form gallstones as well.

Gallbladder motility and contractility

Conditions or defects that stop the gallbladder from fully emptying may lead to the concentration of bile, leading to gallstone formation.

Gallstone types

Most gallstones in developed countries are cholesterol gallstones (85%). However, other types are more common in the rest of the world.

In developing countries, pigmented stones are more common due to the prevalence of bacterial infections, biliary parasites and stasis. Pigmented stones in developed countries tend to occur due to stasis, often as a result of inflammatory biliary diseases or neoplasms, such as primary sclerosing cholangitis and cholangiocarcinoma.

TypeCompositionPrevalenceSpecific risk factorsRadiological findings
Cholesterol gallstoneBile supersaturated with cholesterol, at least 90% cholesterol37-86% of all gallstones    High cholesterol intake or depleted bile saltsRadiolucent on x-ray    
Pigmented gallstone (brown or black)Black gallstones are mostly made of bilirubin.   Brown stones may also contain calcium salts of fatty acid, cholesterol and mucin2-27% of all gallstones    Haemolytic diseasesRadiolucent on x-ray    
Calcium gallstoneCalcium1-17% of all gallstonesGeneral gallstone risk factorsRadiopaque on x-ray  
Mixed gallstoneMixture of cholesterol, bilirubin and calcium salts4-16% of all gallstonesGeneral gallstone risk factorsRadiological features depend on the calcium content of the stone, with more calcium increasing its opacity on x-ray

Clinical features

The majority of gallstones (90%) are asymptomatic. People usually begin experiencing symptoms when gallstones produce inflammation, obstruct the biliary tree and/or migrate to other organs.

Biliary colic: Uncomplicated gallstone disease

Uncomplicated gallstone disease refers to biliary colic in the absence of associated complications, such as cholecystitis, ascending cholangitis and gallstone pancreatitis. In other words, uncomplicated gallstone disease presents with pain only and has no features of inflammation.

Biliary colic is caused by obstruction of the cystic duct or, less frequently, the common bile duct (also known as choledocholithiasis). This usually presents with acute abdominal pain characterised by:

  • Site: Usually upper right quadrant pain and tenderness
  • Onset: Episodic pain that usually self-resolves. Note that biliary colic is not ‘true colic’ as pain intensity does not fluctuate following onset
  • Timing: Pain lasts from minutes to hours
  • Radiation: may radiate to the back
  • Associated factors: often triggered by/after eating
  • Severity: Constant and severe abdominal pain.

Nausea may also present alongside abdominal pain. In common bile duct obstructions, obstructive jaundice may also occur. 

Complicated gallstone disease

It is important to also recognise signs of complicated gallstone diseases such as cholecystitis, ascending cholangitis and gallstone pancreatitis. Unlike those with biliary colic, these patients may deteriorate quickly and may need urgent medical or surgical attention. They may present with:

  • Prolonged right upper quadrant pain
  • Unstable observations:
    • Tachycardia
    • Tachypnoea
    • Hypotension
    • Hypoxia
    • Pyrexia
  • Reduced consciousness/GCS score
  • Central abdominal pain
  • Bruising of central abdomen or the flanks

Investigations

Blood tests

InvestigationFindings
Serum Liver Function Tests (LFT)Normal in uncomplicated cholelithiasis Alkaline phosphatase (ALP), bilirubin and alanine aminotransferase (ALT) may be raised in common bile duct obstructions
Full Blood CountElevated white cell count may indicate active inflammation or infection and can be suggestive of complications
Serum lipase & amylaseIf elevated above 3x normal amounts, suggests acute pancreatitis. Otherwise, can be used to exclude pancreatitis

Imaging

As most gallstones are radiolucent, the gold-standard investigation is abdominal ultrasound.  Further imaging investigations revolve largely around modern technology like Magnetic Resonance Cholangiopancreatography (MRCP), whereas Endoscopic Retrograde Cholangiopancreatography (ERCP) is predominantly reserved for therapeutic objectives and Computer Tomography (CT) is used to look for intra-abdominal complications.

InvestigationFindings
Abdominal ultrasoundCan detect gallstones and bile duct dilatation with a high sensitivity and specificity.
MRCPIdentify stones in gallbladder and biliary tree
ERCPAlthough can be used for imaging, its primary role is for therapeutic procedures given its risk of causing pancreatitis
Abdominal CT scanNormal in uncomplicated disease Can detect presence of gallstones, biliary tree dilatation and pancreas involvement

Management

The management of gallstones depends on the patient’s presentation and can range from not intervening to surgical interventions.

Asymptomatic gallstones

Gallstones are often identified incidentally as part of other investigations and should not be treated if both gallbladder and biliary tree are healthy.

The vast majority of asymptomatic gallstones do not require treatment. Certain patient groups (such as those with porcelain gallbladder) may be offered prophylactic cholecystectomy if at high risk of gallstone disease or gallbladder carcinoma.

Uncomplicated symptomatic gallstones

Treat biliary colic with simple analgesics, such as non-steroidal anti-inflammatory drugs (NSAIDs) and paracetamol. Severe symptoms may be alleviated by opioids. Patients with symptomatic gallstone should be offered laparoscopic cholecystectomy, which is usually done as an elective procedure.

Complicated symptomatic gallstones

The underlying cause should be treated. Options may range from conservative/medical to surgical operations depending on the complication and may include emergency cholecystectomy.

Complications

Apart from biliary colic, gallstones can also lead to:

  • Cholecystitis
  • Ascending cholangitis
  • Pancreatitis
  • Empyema of the gallbladder
  • Fistula formation between gallbladder to duodenum or colon
  • Gallstone ileus (as a result of a gallstone obstructing bowels following fistula formation and migration)
  • Mirizzi’s syndrome: gallstone lodged in cystic duct or at the neck of the gallbladder can apply pressure on the common hepatic duct, producing obstructive jaundice
  • Cholangiocarcinoma

References

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