Gallbladder Hydrops Size Criteria
Gallbladder hydrops is diagnosed when the transverse diameter exceeds 5 cm, representing pathologic distension beyond normal gallbladder dimensions. 1
Defining Hydrops
The diagnosis of gallbladder hydrops is based on exceeding normal gallbladder measurements:
- Normal gallbladder transverse diameter should not exceed 5 cm under normal circumstances 1
- When the transverse diameter exceeds this 5 cm threshold, it indicates cholecystitis or pathologic distension consistent with hydrops 1
- Normal gallbladder length is approximately 7-10 cm, so hydrops represents gross increases beyond these dimensions 1
Clinical Context for Diagnosis
The key distinguishing feature of hydrops is marked distension of the gallbladder, often described as a "grossly enlarged" or "very much distended" gallbladder that may extend to the iliac crest. 2
Additional diagnostic considerations:
- Wall thickness should be evaluated alongside size measurements, with normal wall thickness being less than 3 mm 1, 3
- Hydrops typically presents with a palpable right upper quadrant mass on physical examination 2
- The condition can occur in acalculous settings, particularly in children with viral infections or Kawasaki disease 2, 4
Common Pitfalls to Avoid
- Do not diagnose pathology based solely on size measurements without considering wall thickness, pericholecystic fluid, and sonographic Murphy's sign 1
- Avoid measuring the gallbladder through bowel gas or when patient positioning limits adequate visualization 1
- Remember that while transverse diameter >5 cm suggests hydrops, the clinical presentation and associated findings must support the diagnosis 1, 2
The 5 cm transverse diameter cutoff provides a clear threshold for identifying pathologic gallbladder distension consistent with hydrops, distinguishing it from normal anatomic variation. 1