Final answer:
A 67-year-old woman with an altered mental status, fever, tachycardia, physical discomfort in the right upper quadrant, and ultrasound findings of gallbladder wall thickening and pericholecystic fluid without gallstones likely has acalculous cholecystitis.
Step-by-step explanation:
The most likely diagnosis for a 67-year-old woman presenting with confusion, an elevated temperature, a higher pulse rate, and right upper quadrant discomfort on physical examination, with an ultrasound showing pericholecystic fluid and gallbladder wall thickening without gallstones, is acalculous cholecystitis. Acalculous cholecystitis is a form of cholecystitis that occurs without the presence of gallstones and can be seen in critical illnesses or other conditions that impact blood flow to the gallbladder.
Symptoms may mimic those of calculous cholecystitis (gallbladder inflammation due to gallstones), but there is an absence of stones on imaging. Instead, the diagnosis is generally suggested by signs of inflammation such as gallbladder wall thickening and pericholecystic fluid on ultrasound. This condition is seen in hospitalized or debilitated patients and needs prompt attention as it can be life-threatening. Since the patient is already on home hospice care, the management strategy will consider her overall prognosis and goals of care, which may differ from the standard surgical intervention typically indicated for acalculous cholecystitis.