An inflamed gallbladder is swollen, red, and thick-walled, often ballooning well beyond its normal size. What it looks like depends on whether you’re viewing it on an ultrasound screen, a CT scan, or directly during surgery, and whether the inflammation is a sudden (acute) episode or the result of years of recurring problems.
What Surgeons See During Surgery
When a surgeon views an acutely inflamed gallbladder directly, the changes are dramatic. A healthy gallbladder is a small, smooth, greenish sac tucked under the liver. An inflamed one is visibly enlarged, with a puffy, waterlogged wall. The outer surface loses its normal sheen and becomes dull, often covered in patches of yellowish-white material from the inflammatory response. Fatty tissue from nearby organs may stick to the surface in adhesions, and fluid frequently pools around the organ.
Color changes tell a story about severity. A mildly inflamed gallbladder looks congested and reddened. As inflammation worsens, the surface can turn deep red, purple, or even black, signaling that blood flow to the wall is compromised and tissue is starting to die. That progression toward gangrene is a surgical emergency.
What an Inflamed Gallbladder Looks Like on Ultrasound
Ultrasound is the first imaging test used when gallbladder inflammation is suspected, and the signs are well established. The hallmark finding is a thickened gallbladder wall. A normal wall measures about 3 mm or less; anything above 3.5 mm is highly accurate in predicting disease, though a normal measurement doesn’t completely rule out inflammation.
Other ultrasound signs include:
- Distention. The gallbladder stretches beyond 4 cm in width, looking like an overfilled balloon rather than a slim pouch.
- Pericholecystic fluid. A thin rim of fluid appears around the outside of the gallbladder, indicating the inflammation is spreading to surrounding tissue.
- Sludge. Thick, murky bile collects inside the gallbladder, showing up as a shifting gray layer that settles to the bottom. Unlike gallstones, which appear as bright white spots casting dark shadows behind them, sludge is dimmer and produces no shadow.
- Gallstones. Bright, echogenic spots with distinct shadows behind them are visible in most cases of acute inflammation. When the gallbladder is packed with stones, the ultrasound shows a characteristic pattern: a bright line from the gallbladder wall, a thin dark line of bile, then a wall of shadow cast by the stones below.
During the ultrasound, the technician presses the probe directly over the gallbladder. If this pressure produces sharp, focused tenderness right at that spot, it’s called a positive sonographic Murphy sign. This finding is very specific for acute inflammation, correctly identifying a healthy gallbladder about 92% of the time, though its sensitivity is lower at around 41%, meaning it misses a fair number of true cases.
What It Looks Like on CT
CT scans reveal a broader picture, especially of what’s happening in the tissue surrounding the gallbladder. The classic signs on CT include wall thickening, distention, and an intensely bright inner lining where contrast dye concentrates in the inflamed tissue. In a study of 29 patients with confirmed cholecystitis, 59% showed wall thickening on CT, 52% had inflammatory streaking in the surrounding fat, 41% had distention, and 31% had fluid accumulation around the organ.
That inflammatory streaking in the surrounding fat, called fat stranding, looks like hazy, cloudy lines radiating outward from the gallbladder into the normally dark, clean-looking fat tissue around it. It’s a reliable sign that inflammation is actively spreading, though it can also appear with other abdominal conditions unrelated to the gallbladder.
CT is also better than ultrasound at catching complications. If the gallbladder wall shows irregular gaps or breaks, that suggests perforation. If the liver tissue immediately adjacent to the gallbladder lights up unusually bright with contrast, it means the inflammation is irritating the liver surface.
Acute vs. Chronic Inflammation
Acute and chronic cholecystitis produce distinctly different appearances. Acute inflammation creates a swollen, distended gallbladder surrounded by fluid and inflamed tissue. Everything looks enlarged, angry, and wet.
Chronic inflammation tells a different story. The gallbladder has been irritated repeatedly over months or years, and instead of swelling, it often shrinks. The walls thicken from scar tissue rather than fluid. Gallstones are almost always present. The surrounding tissue typically looks calm, with no fluid or fat stranding. On imaging, a chronically inflamed gallbladder can appear contracted and dense, like a small, hard pouch rather than a distended sac.
Porcelain Gallbladder
One striking form of chronic inflammation produces a “porcelain gallbladder,” where calcium deposits infiltrate the wall itself. On X-ray or CT, the gallbladder wall glows white, either as a continuous bright band of calcification or as scattered flecks of calcium. The name comes from the bluish color and brittle texture of the wall when seen directly. About 95% of patients with this condition also have gallstones.
Porcelain gallbladder is usually discovered by accident on imaging done for other reasons, because most people with it have no symptoms. It carries a small but real increased risk of gallbladder cancer, which is why surgical removal is typically recommended even in the absence of symptoms.
When Inflammation Turns Dangerous
The most concerning visual changes signal that the gallbladder wall is dying. A gangrenous gallbladder shows irregular, patchy areas where the inner lining has sloughed off, creating ragged membranes floating inside the organ. On CT, the wall may appear unevenly thickened or show areas that fail to pick up contrast dye, indicating dead tissue with no blood flow. The surrounding fat stranding and fluid tend to be more extensive than in uncomplicated cases.
On the surgical table, gangrenous tissue is unmistakable: the wall turns deep purple or black and becomes fragile enough to tear. If the wall perforates, a pocket of infected fluid or abscess forms next to the gallbladder, visible on imaging as a dark, irregular collection of fluid in an area where none should exist. Fluid specifically in the narrow space between the gallbladder and the liver is a strong indicator of perforation rather than simple inflammation.