Final answer:
The nurse suspects cholecystitis, an inflammation of the gallbladder typically caused by gallstones, which can obstruct the bile duct and is often triggered by eating high-fat meals.
Step-by-step explanation:
Based on the symptoms of right upper quadrant pain that radiates toward the right upper portion of the back and is triggered by the consumption of rich, high-fat foods, the disorder the nurse suspects is cholecystitis. Cholecystitis is an inflammation of the gallbladder often caused by gallstones, which can obstruct the outflow of bile and lead to the symptoms described. This condition is particularly related to eating high-fat meals as the gallbladder releases bile to aid in the digestion of fats. Symptoms may be exacerbated after consuming these types of foods when the gallbladder is inflamed or obstructed by gallstones.