When assessing a client with diarrhea, which finding indicates hypokalemia?

Muscle weakness is a classic sign of hypokalemia, which is a condition characterized by lower-than-normal levels of potassium in the blood. Potassium is crucial for the proper functioning of muscles, including those that make up the heart. When potassium levels drop, it can lead to impaired muscle function, resulting in symptoms such as weakness and fatigue.

In the context of a client with diarrhea, which can cause loss of electrolytes, including potassium, muscle weakness can specifically indicate that the body is not retaining adequate potassium. This makes it a vital symptom to monitor in patients experiencing diarrhea.

While rapid heartbeat, severe abdominal pain, and low blood pressure can also be associated with various conditions, they are not as directly indicative of hypokalemia as muscle weakness. Rapid heartbeat may relate to a variety of issues including anxiety or dehydration, abdominal pain can be a result of gastroenteritis or other gastrointestinal disturbances, and low blood pressure could stem from multiple causes, such as dehydration or shock, but these don't pinpoint hypokalemia specifically. Hence, muscle weakness is recognized as the more definitive sign of low potassium levels in this scenario.