Overview
Gallstones (cholelithiasis) are stones formed within the gallbladder. In developed countries, over 90% of gallstones consist of cholesterol. In some people, gallstones can pass out of the gallbladder into the cystic duct, the common bile duct, or the pancreatic duct.
- Biliary colic – colic (crampy pain) due to the gallbladder contracting while obstructed due to gallstones
- Cholecystolithiasis – gallstones in the gallbladder
- Choledocholithiasis – gallstones in the common bile duct
Around 80% of people with gallstones are asymptomatic and will never know they have them.
Types
The overall types of gallstones include:
- Cholesterol gallstones – the most common in developed countries
- Pigmented gallstones – darker stones made of bilirubin and calcium salts
- Mixed stones – a combination of cholesterol and pigment stones
Pathophysiology
Cholesterol gallstones
When bile contains too much cholesterol and not enough bile salts, cholesterol gallstones form. Reduced gallbladder motility can result in overly concentrated bile (cholesterol supersaturation) and certain proteins in the liver and bile can promote crystal formation, increasing the risk of gallstones.
Increased levels of oestrogen (e.g. hormone replacement therapy or the combined oral contraceptive pill) can increase cholesterol levels in bile and reduce gallbladder motility, increasing the risk of gallstone formation.
Pigmented gallstones
Pigmented gallstones are made of bilirubin and are present where bilirubin levels are increased, such as liver cirrhosis, biliary tract infection, and haematological disorders leading to increased haemoglobin turnover (such as chronic haemolytic anaemia, sickle cell anaemia, thalassaemia, hereditary spherocytosis etc.), or impaired bile salt reabsorption (e.g. Crohn’s disease affecting the ileum). Bilirubin crystallises, forming stones.
Causes and Risk Factors
Cholesterol gallstones
The risk factors for cholesterol gallstones are often remembered using the aide-mémoire ‘fair (white ethnicity), fat, fertile, female, and forty’. Causes of cholesterol gallstones include:
- Obesity
- Increased age
- Female sex
- Some drugs:
- Ceftriaxone
- Oestrogen-containing drugs: – (e.g. the combined oral contraceptive pill or hormone replacement therapy)
- Rapid weight loss
- Total parenteral nutrition
Pigmented gallstones
The risk factors for pigmented gallstones include factors that increase bilirubin:
- Hepatobiliary disorders:
- Liver cirrhosis
- Biliary infection
- Conditions predisposing to haemolysis:
- Sickle cell disease
- Thalassaemia
- Hereditary spherocytosis
- Other haemolytic anaemias
- Ileal disorders – due to impaired bile salt reabsorption such as
- Crohn’s disease affecting the ileum
- Ileal resection
Epidemiology
- In developed countries, cholesterol stones make up to 90% of gallstones
- Around 80% of people have asymptomatic gallstones and may never know they have them
- Women are at an increased risk, particularly if they are in their 40s, overweight, white, and use oestrogen-containing drugs
Presentation
Overview
Gallstones are often asymptomatic and discovered incidentally. Around 25% of people develop symptomatic disease which can present with:
- Biliary is the most common presentation (~56%):
- Episodic, crampy, right upper quadrant pain lasting 30 minutes – 8 hours
- Often associated with nausea and vomiting, but not associated with fever or abdominal tenderness
- Often triggered after meals, particularly if they are fatty as the hormone cholecystokinin is released, which promotes gallbladder contraction
- Acute cholecystitis is the second most common presentation (~36%):
- Right upper quadrant pain becomes constant with additional fever and right upper quadrant tenderness
- Murphy’s sign is positive
- Obstructive jaundice:
- Due to partial or complete blockage of the common bile duct, resulting in accumulation of bile pigments in the blood
- Yellow discolouration of the skin, dark urine, and pale stools
- Most commonly due to stones that pass from the gallbladder to the common bile duct or rarely due to Mirizzi’s syndrome
- Acute cholangitis:
- Charcot’s triad: fever and rigours, right upper quadrant pain, and jaundice
- Acute pancreatitis:
- Common bile duct stones obstruct the flow of pancreatic secretions which can precipitate acute pancreatitis
- Other complications (discussed below)
Some people may have vague and non-specific symptoms of epigastric pain and indigestion, especially after eating fried or fatty foods.
Investigations
Overview
In all people with suspected gallstones, the following initial tests are offered:
- Abdominal ultrasound:
- May identify gallstones, however, if they are not seen on an ultrasound, this does not exclude their existence
- Liver function tests (LFTs):
- Usually normal, however, if gallstones are present in the common bile duct, this can cause elevated bilirubin and ALP
If an ultrasound shows no gallstones but clinical suspicion remains elevated, consider a referral for the following:
- Magnetic resonance cholangiopancreatography (MRCP):
- Indicated if an ultrasound does not show gallstones but the bile duct is dilated and/or LFTs are abnormal
- Endoscopic ultrasound (EUS):
- If MRCP cannot provide a diagnosis
Management
Asymptomatic gallstones
- Asymptomatic gallstones within a normal gallbladder and normal biliary tree:
- Treatment is often not required unless the patient becomes symptomatic
- Asymptomatic gallstones in the common bile duct:
- Refer for bile duct clearance and laparoscopic cholecystectomy
- Despite being asymptomatic, common bile duct stones can predispose to serious complications including acute cholangitis and pancreatitis
Symptomatic gallstones
- Arrange immediate hospital admission if any of the following are suspected:
- Acute cholecystitis
- Acute cholangitis
- Acute pancreatitis
- Refer urgently to gastroenterology if any of the following apply:
- A person with known gallstones that develops jaundice
- If there is clinical suspicion of biliary obstruction (e.g. significantly abnormal LFTs)
All other patients with symptomatic gallstones (usually biliary colic) should be referred for consideration of laparoscopic cholecystectomy. The urgency of referral depends on clinical judgement.
While patients are awaiting a secondary care appointment, manage pain:
- Intermittent mild-moderate pain: paracetamol or an NSAID
- Severe pain: IM diclofenac (if not contraindicated)
- Pain that cannot be managed in primary care: arrange emergency hospital admission
Complications
- Biliary colic
- Acute cholecystitis
- Acute pancreatitis
- Obstructive jaundice
- Acute cholangitis
- Gallstone ileus – rare:
- Due to gallstones obstructing the small intestine leading to small bowel obstruction
- An abdominal X-ray may show Rigler’s triad (not to be confused with Rigler’s sign):
- Small bowel obstruction
- A gallstone outside of the gallbladder
- Air in the biliary tree
Prognosis
- ~80% of people with gallstones are asymptomatic and will never know they have them.
- Up to 4% of people with asymptomatic gallstones develop symptoms annually – prognosis varies depending on what the symptoms are due to (i.e. biliary colic, acute cholangitis, acute pancreatitis etc.).
