Cholelithiasis

Just by seeing the junk foods, everyone tends to salivate. These delicious foods have high-fat content. We people, without knowing its harmful effects, often eat a lot of them.

When we eat food rich in fat, a magical substance called bile is released from the gallbladder. This substance helps in the absorption and digestion of fatty food. This magical substance contains water, bile acids, bile salts, lecithin, cholesterol, electrolytes, and conjugated bilirubin, which together facilitate fat metabolism.

Cholelithiasis is a condition in which a concrete hard substance forms in the gallbladder and disturbs its functions. It is one of the most common conditions affecting the gallbladder, commonly called gallstones. Depending on what these stones are made up of, they are classified into 

1. Cholesterol stones.
2. Pigment stones.
3. Mixed stones (cholesterol mixed with calcium salts)

Out of these, mixed stones are the most common variety seen.

How it forms?

Cholesterol is a water-insoluble substance. It is made water-soluble by binding with bile acids, bile salts, and lecithin, which are amphibolic. Cholesterol stones are formed when either excess cholesterol or deficient bile results in supersaturation of bile.

Now, these excess cholesterols tend to form stones. Another promoter for stone formation is gallbladder hypomobility resulting in bile stasis and promoting separation of bile acids and cholesterol. This ultimately leads to stone formation. 

Pigment stones are formed due to the increased production of the bilirubin. It can also be due to infection of the biliary tract. Depending on the cause, it can be:

• Brown stones: These are due to the infection of the biliary tract. Organisms commonly involved in these cases are E.coli, Ascaris lumbricoides, Clonorchis Sinensis (liver fluke). This infection leads to the hydrolysis of conjugated bilirubin to an unconjugated form. This form attracts more calcium resulting in stone formation.
• Black stones: These are formed due to increased hemolysis resulting in an increased concentration of unconjugated bilirubin.

Morphology of stones

Cholesterol stones are pale yellow, round to ovoid, hard surface, and glistening on the cut section. 

Brown stones have greasy or soaplike consistency.

Black stones are smaller in size, more in number, soft spiculated, and molded surface.

Who is likely to get it?

Cholesterol stones are more common among,

• 5 Fs. Fat, Fertile, Female, Forty, Fair.
• In obese people, high cholesterol levels favor stone formation.
• Oestrogens can increase cholesterol levels in our body. People using oral contraceptive pills and pregnancy states produce a high estrogen state.
• Rapid weight reduction can result in the alteration of the bile composition leading to stone formation.
• Gallbladder hypomobility, as in total parenteral nutrition, long-term intravenous fluids, and increased estrogen levels.
• People on drugs such as cholestyramine and clofibrate. These drugs favor stone formation.
• Ileal disease, like Crohn's disease and patients undergoing ileal resection, is likely to get cholelithiasis as a result of disturbed enterohepatic circulation (low bile levels).
• Pigment stones are common in,
• Infection of the biliary tract.
• South-east Asians are more prone to get pigment stones.
• Increased bilirubin levels resulting from hemolytic conditions such as sickle cell anemia, hereditary spherocytosis, malaria, thalassemia, etc.

Patient Presentation

Patients are usually asymptomatic; however, some may have intermittent right hypochondrial pain. The pain usually occurs after a fatty meal due to the contraction of the gallbladder for the release of bile.

If the gallstones are large, it can obstruct the gallbladder and result in acute cholecystitis. Here, the patient has a fever and persistent tachycardia. On examination, the gallbladder is not palpable as prolonged inflammation of the organ will result in the fibrosis of the gallbladder (Courvoisier’s law). Patients can have pain on taking deep inspiration when palpating over the right hypochondrium (Murphy’s sign positive).

Patients can have a fever in case of any biliary infection. There can be yellowish discoloration of the sclera due to increased bilirubin levels. 

If the gallstones escape from their house (gallbladder) and reach the street (common bile duct), it results in cholangitis. In cholangitis, Charcot’s triad (intermittent fever, intermittent pain, intermittent jaundice) is seen.

Work Up

USG abdomen is the first line of investigation. Gallstones are seen as hyperechoic structures with the presence of the distal acoustic shadow. Acoustic shadow will be absent in case of cholecystitis, differentiating it from gallstones.

Plain X-ray abdomen can show radio-opaque mixed stones. Pure cholesterol stones are radiolucent and are not seen on X-ray.

Total blood count, liver function tests are taken. MRCP, ERCP may be required to rule out any complications.

Sequelae of Cholelithiasis

• Acute cholecystitis and chronic cholecystitis
• Cholangitis
• Pancreatitis occurs if the stone gets lodged in the junction of the common bile duct and pancreatic duct. This can result in the backflow of the pancreatic fluid and the release of enzymes producing inflammation.
• Mucocele of the gallbladder
• Empyema of the gallbladder
• Mirizzi syndrome, where the pressure effect of gallstones on the gallbladder results in wall necrosis and leads to cholecystocholedochal fistula or cholecystoduodenal fistula.
• Carcinoma gallbladder.

Differential Diagnosis

Based on clinical presentation,

1. Perforated peptic ulcer
2. Acute appendicitis
3. Myocardial infarction

Radio-opaque shadow in X-Ray,

1. Kidney stones
2. Calcified 12th rib tip
3. Radio-opaque foreign body
4. Calcified adrenal tumor
5. Calcified renal lesions

Treatment

To relieve pain, oral analgesics or parenteral analgesics are given. In the case of pigment stones (brown-stones), intravenous antibiotics are administered.

Laparoscopic cholecystectomy is a surgical procedure done nowadays. Open cholecystectomy is preferred if there are any complications. Extracorporeal shockwave lithotripsy can be done.

“Control your tongue and protect your gallbladder.”

References:

1. Bailey and Love’s Short Practice of Surgery 27^th edition, Page no:1198-1200
2. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3899548/
3. https://www.ncbi.nlm.nih.gov/books/NBK470440/

Author’s Footnote

Acalculous cholecystitis is an inflammatory condition of the gallbladder in the absence of any evidence of gallstones. It is one of the most commonly missed diagnoses and carries a high mortality. It is most common in patients recovering from burns, trauma, and major surgery like coronary artery bypass.

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