Gallstones vs Kidney Stones: Causes, differences, and key symptoms

Sometimes it is hard to know what is going on inside your body. Though, stomach pain and/or discomfort can be alarming but that pain can be dismissed for minor stomach issues. The problem arises when the pain becomes unbearable, persistent and difficult to deal with. Two common conditions that can cause sharp pain are gallstones and kidney stones. While they both involve "stones" forming in the body, they are very different in terms of location, causes and treatment. Understanding the differences can help one recognise the early signs and seek appropriate care.

Gallstones are solid particles that form in the gallbladder, which is a small organ present under the liver, that stores bile, a digestive fluid that helps break down fats. These stones can vary in size, from tiny grains to larger, more troublesome stones.

Common causes include:

High cholesterol in the bile
Excess bilirubin
Poor gallbladder emptying

Gallstones develop silently, but when they block the bile ducts, one may notice:

Sudden, intense pain in the upper right or middle abdomen

Pain that can radiate to the back or right shoulder

Nausea or vomiting

Indigestion, bloating or gas after fatty meals

Pain from gallstones, often called biliary colic, usually comes in waves and can last from a few minutes to several hours. According to National Institute of Health, in the United States, approximately 14 million women and 6 million men between the ages of 20 and 74 have gallstones.

Gallstones are solid particles that form in the gallbladder, a small organ under the liver that stores bile, a fluid which help digest fats. Most gallstones about 80% are made primarily of cholesterol, which is why they are termed as cholesterol gallstones. A study from 1980, The New England Journal of Medicine, titled, "Cholesterol crystals and the formation of cholesterol gallstones"​

To do this, they examined bile samples from
People with gallstones (both asymptomatic and symptomatic)

People with pigment stones (stones made mostly of bilirubin), and

People without gallstones

They looked at:
How much cholesterol was dissolved in the bile and whether the cholesterol crystals are present or not.

In patients with asymptomatic gallstones, the average cholesterol saturation was 142% (normal would be below 100%). Cholesterol crystals were found in people with cholesterol gallstones, not pigment stones, in all 19 patients with cholesterol stones, crystal were present in their bile. But in those with pigment stones, no crystals were found. The study concluded that Cholesterol crystallisation is a prerequisite for the formation of cholesterol gallstones, meaning the gallstones cannot form until cholesterol turns into solid crystals first.​

Kidney stones are hard deposits of minerals and salt that form in the kidneys. Unlike gallstones, kidney stones often travel through the urinary tract, which can cause unbearable pain. According to National Kidney Foundation, more than 500,000 people go to emergency room because of kidney stones. About 1 out of every 10 people will get a kidney stone at some point in their life

Common causes include
​
Dehydration
High salt intake
Certain medical conditions such as gout

Kidney stones usually present with symptoms when they start moving through the urinary tract, these include:

Blood in urine
Nausea and vomiting
Frequent urination
Severe, cramping pain in the back, side or lower abdomen

Other causes listed by National Kidney foundation are: Diabetes, gastric bypass surgery, inflammatory bowel disease, hyperthyroidism, chronic UTI.

The pain of kidney stones, sometimes called renal colic, often comes in waves and is considered one of the most intense types of pain.

The most critical step to avoid kidney stones is to maintain excellent hydration by drinking plenty of water throughout the day, ensuring your urine is light and clear, which effectively dilutes the minerals that form crystals. Beyond hydration, the diet must be adjusted by significantly reducing high-sodium foods (like canned and processed items) and limiting the intake of animal protein (red meat, poultry, and fish), as both high salt and excessive protein increase the amount of calcium and uric acid the kidneys must filter.