Acute gastritis is an inflammation of the mucosa. It is transient, may involve local irritants such as aspirin: food contamination, caffeine, alcohol. It is self- limiting and is very serious.

A. 60–89 mL/min/1.73m²: This range indicates mildly decreased GFR, often classified as Stage 2 chronic kidney disease. Renal function is still relatively preserved and not considered renal failure at this stage.

B. 30–59 mL/min/1.73m²: This reflects a moderate decrease in GFR, typically Stage 3 CKD. Although kidney function is significantly impaired, it is not yet categorized as renal failure.

C. 15–29 mL/min/1.73m²: This GFR indicates severe kidney impairment and is classified as Stage 4 CKD. While this stage shows significant dysfunction, renal failure is generally diagnosed at lower values.

D. <15 mL/min/1.73m²: A GFR below 15 signals end-stage renal disease (ESRD), also referred to as renal failure. At this stage, dialysis or kidney transplantation is usually necessary to sustain life.

A. Diverticulitis: This condition involves inflammation or infection of diverticula (small pouches) in the colon wall, typically presenting with localized pain and not characterized by “cobblestone” appearance or skipped lesions seen on colonoscopy.

B. Crohn's Disease: The description of “cobblestone” mucosa, skipped lesions, and thickened bowel walls resembling “lead pipes” are classic features of Crohn’s disease. It can affect any part of the gastrointestinal tract and presents with patchy, transmural inflammation causing thickening and characteristic endoscopic findings.

C. Diverticulosis: This condition involves the presence of diverticula without inflammation. It does not cause the cobblestone or skipped lesion appearance seen in inflammatory bowel disease and is generally asymptomatic unless complicated by diverticulitis.

D. Ulcerative Colitis: This disease causes continuous inflammation usually starting in the rectum and extending proximally, leading to a loss of haustral markings but does not typically present with skipped lesions or a cobblestone appearance. The colon wall tends to be thin rather than thickened.