Twenty-year-old “Drew” observes his grandmother “Mimi” decline as she stubbornly refuses treatment for her chronic kidney disease. Students examine some basic markers of declining renal function and predict which acid-base disorder Mimi has, as well as the expected compensation. When Mimi develops pneumonia, an existing acid-base disorder becomes life-threatening. Students examine her lab results and explain the changes in pH, PCO2, and bicarbonate levels. This case study was written for a two-semester anatomy and physiology course taken by nursing, nutrition, athletic training, and other allied health majors in their first or second year. It could also be adapted for use in a high school anatomy and physiology course, or an upper-level physiology or pathophysiology course.