Gallstones Explained: Biliary Colic, Cholecystitis and Why Pain Can Follow a Fatty Meal

A patient tells you they were absolutely fine all day, ate dinner, and a couple of hours later developed severe pain under the right ribs. Someone mentions gallstones. But why should a stone sitting in the gallbladder suddenly hurt after a meal?

The easiest way to understand gallstone disease is not to memorise separate lists for biliary colic, cholecystitis, jaundice and pancreatitis. Start with what bile normally does, then follow the stone and see what changes.

Follow the bile: how a gallstone becomes a problem

The liver continuously produces bile, a fluid containing bile acids, phospholipids, cholesterol, bilirubin, electrolytes and water. Bile helps the small intestine digest and absorb fats and fat-soluble vitamins.

Between meals, some bile is diverted through the cystic duct into the gallbladder, where it is stored and concentrated. When food enters the duodenum, particularly fat and protein, gastrointestinal signalling includes release of cholecystokinin (CCK). CCK contributes to gallbladder contraction and relaxation of the sphincter of Oddi, helping bile move through the biliary tract into the duodenum.

Follow the normal route: liver produces bile → bile enters the hepatic ducts → bile can pass through the cystic duct into the gallbladder for storage → after a meal the gallbladder contracts → bile travels through the cystic duct and common bile duct → bile enters the duodenum.

Gallstones form when substances within bile precipitate and gradually form solid material. In the UK and other Western populations, most gallstones are cholesterol stones, although pigment stones also occur. Formation is not simply a case of eating too much fat. It reflects a combination of bile composition, crystal formation, gallbladder emptying and other individual risk factors.

A gallstone can sit quietly in the gallbladder and cause no symptoms at all. Many people only discover gallstones incidentally during imaging performed for something else. NICE advises that asymptomatic gallbladder stones in an otherwise normal gallbladder and biliary tree generally do not require treatment unless symptoms develop. The problem usually begins when a stone moves into a position where it obstructs bile flow.

Now imagine the gallbladder contracting after food enters the small intestine. If the cystic duct is open, bile can leave. If a gallstone becomes lodged at the gallbladder outlet or within the cystic duct, the gallbladder is contracting against an obstruction. Pressure rises, the wall stretches and visceral sensory pathways are stimulated.

Meal → CCK contributes to gallbladder contraction → stone obstructs outflow → intraluminal pressure rises → visceral pain develops.

This helps explain why some patients notice symptoms after meals, particularly foods that trigger their symptoms. However, do not turn “fatty meal” into a diagnostic rule. Gallstone pain can occur at other times, and right upper-quadrant or epigastric pain has many possible causes.

If the obstruction is temporary and the stone moves so that bile can flow again, pressure falls and the episode settles. This is the physiology behind biliary colic. The name can be misleading: “colic” can sound like brief waves of cramping, but gallstone-related biliary pain is commonly severe and relatively steady. NHS guidance describes pain in the centre of the abdomen or beneath the right ribs that can last longer than 30 minutes and up to several hours, sometimes with nausea or vomiting.

So if a patient says, “It was agony for three hours and then suddenly eased,” transient obstruction makes physiological sense. It does not prove the diagnosis, but the mechanism explains the symptom pattern.

If the stone does not move, the situation changes. Persistent cystic-duct obstruction allows continuing gallbladder distension and initiates inflammation of the gallbladder wall. This is acute cholecystitis. It is not simply “worse gallstones”: the obstruction has persisted long enough for an inflammatory process to develop.

Persistent cystic-duct obstruction → gallbladder distension and inflammation → persistent right upper-quadrant pain and tenderness, often with systemic or inflammatory features.

NHS guidance describes acute cholecystitis as potentially serious. Pain is usually persistent rather than settling within a few hours, and the patient may have marked right upper-quadrant tenderness. Fever, nausea, vomiting and evidence of inflammation may also occur. For a student nurse, the changing pattern matters. A patient who previously had self-limiting episodes but now has persistent pain, tenderness, fever or physiological deterioration needs reassessment and escalation rather than reassurance that this is “their usual gallstones”.

When the stone moves further

The cystic duct is only one place a stone can cause trouble. A stone can leave the gallbladder and enter the common bile duct. This is a common bile duct stone, or choledocholithiasis.

Think anatomically. Bile produced by the liver normally drains through the hepatic ducts into the common bile duct. If that pathway becomes obstructed, bile components can accumulate upstream rather than reaching the intestine normally. The patient may develop jaundice, dark urine, pale stools and itching, and liver blood tests may show a cholestatic pattern.

If infection develops within an obstructed biliary system, acute cholangitis can occur. This can progress to sepsis and requires urgent medical assessment and treatment. The traditional Charcot triad is right upper-quadrant pain, fever and jaundice, but real patients do not have to arrive with all three neatly present. Do not wait for a textbook triad before escalating someone who is systemically unwell.

A stone passing towards the distal common bile duct and ampulla can also interfere with pancreatic drainage. This provides the anatomical link between gallstones and acute pancreatitis. Severe epigastric pain, pain radiating towards the back, vomiting or significant deterioration should therefore prompt appropriate clinical assessment rather than being assumed to be uncomplicated biliary colic.

The investigations make more sense when you keep following that anatomy. NICE recommends liver function tests and abdominal ultrasound when gallstone disease is suspected. Ultrasound can identify gallstones and may show features suggesting gallbladder inflammation or biliary dilatation. Liver blood tests help identify evidence that bile flow or hepatobiliary function may be disturbed. Full blood count and C-reactive protein may contribute to assessment of inflammation or infection, while renal function, electrolytes and pancreatic enzymes may be relevant depending on the presentation.

If ultrasound does not show a common bile duct stone but the bile duct is dilated and/or liver function tests are abnormal, NICE advises considering magnetic resonance cholangiopancreatography (MRCP). If MRCP does not provide a diagnosis, endoscopic ultrasound may be considered.

ERCP — endoscopic retrograde cholangiopancreatography — is different from simply taking another picture. It is an invasive endoscopic procedure that can be used therapeutically to clear common bile duct stones in appropriate patients. NICE recommends bile duct clearance for common bile duct stones, either surgically at the time of laparoscopic cholecystectomy or with ERCP before or at the time of surgery. Ultrasound and MRCP primarily help define what is happening; ERCP can also treat selected biliary obstruction.

Management follows the same logic: it depends on what the stones are doing rather than simply whether they exist. Someone with incidentally discovered, asymptomatic gallbladder stones will usually not need treatment solely because stones are present. Once gallbladder stones are symptomatic, NICE recommends laparoscopic cholecystectomy. For acute cholecystitis, NICE recommends early laparoscopic cholecystectomy within one week of diagnosis where appropriate.

Patients with common bile duct stones require bile duct clearance as well as management of the gallbladder. Analgesia, antiemetics, intravenous fluids, antibiotics and other supportive treatments may be required according to the presentation and clinical plan. The student nurse's role is not to select or prescribe these treatments independently, but understanding why they are being used makes monitoring much more meaningful.

Bring it back to the patient

Consider two patients. The first develops severe right upper-quadrant pain after dinner. They feel nauseated, but their observations remain stable and the pain settles after a few hours. Imaging later identifies gallstones. Temporary obstruction producing biliary colic would fit the mechanism.

The second has similar pain, but it does not settle. They become increasingly tender, febrile and tachycardic. The clinical picture has changed: persistent obstruction with inflammation or another complication now needs consideration. If jaundice, rigors, hypotension, confusion or other signs of systemic deterioration appear, concern increases further for biliary obstruction, infection and sepsis.

The lesson is not to diagnose either patient yourself. It is to notice that the trajectory has changed and communicate that clearly.

If you are caring for someone with suspected or confirmed gallstone disease, do more than record “abdominal pain”. Ask where the pain is, when it started, whether it is persistent or has settled, where it radiates and whether similar episodes have happened before. Ask about nausea, vomiting, oral intake and any relationship between symptoms and food.

Look at the patient as well as the diagnosis. Are they jaundiced? Are they shivering or febrile? Is their abdomen increasingly tender or distended? What is happening to their heart rate, blood pressure, respiratory rate, temperature and overall observation trend? Are they maintaining hydration and urine output? Has the pain responded to prescribed analgesia, or is it worsening despite treatment?

Dark urine, pale stools or new jaundice can fit impaired bile flow and should be reported. Persistent vomiting raises concerns around dehydration and electrolyte disturbance as well as the underlying cause.

And remember the differential diagnosis. Right upper-quadrant or epigastric pain is not automatically gallstones. Gastrointestinal, hepatic, pancreatic, cardiac and pulmonary conditions can produce overlapping symptoms. Your job as a student is to assess, recognise deterioration, communicate what you have found and escalate within your level of competence.

If you remember one thing, follow the anatomy: a stone sitting in the gallbladder may cause no symptoms; temporary cystic-duct obstruction can produce biliary colic; persistent cystic-duct obstruction can lead to acute cholecystitis; common bile duct obstruction can impair bile drainage and cause jaundice; obstruction with infection can become cholangitis and sepsis; and distal obstruction can interfere with pancreatic drainage and contribute to gallstone pancreatitis.

Once you understand where the stone is and what it is obstructing, the symptoms, blood tests, imaging and treatment plan stop looking like separate facts and start making physiological sense.

References

National Institute for Health and Care Excellence (NICE). Gallstone disease: diagnosis and management (CG188). Available at: NICE CG188.

National Institute for Health and Care Excellence (NICE). Gallstone disease (QS104). Available at: NICE QS104.

NHS. Gallstones. Available at: NHS gallstones.

NHS. Acute cholecystitis. Available at: NHS acute cholecystitis.

Nursing and Midwifery Council (NMC). The Code. Available at: NMC Code.

This article is for student learning and does not replace clinical assessment, local policy, supervision or individual medical advice.