Which of the following is NOT a differential diagnosis for back pain?

The correct answer is that asthma is not a differential diagnosis for back pain. Back pain typically arises from issues related to the musculoskeletal system, such as muscle sprains, joint problems, or structural issues in the spine. Conditions like kidney stones and cystitis can refer pain to the back due to their proximity to the abdominal and pelvic regions, which can lead to perceived pain in the back area.

Asthma, on the other hand, is primarily a respiratory condition that affects the airways and is characterized by symptoms such as wheezing, difficulty breathing, and chest tightness. While asthma can cause discomfort in the chest and back due to strained breathing or coughing, it is not a primary source of back pain and typically does not feature in the differential diagnosis for this symptom. Understanding the specific conditions that contribute to back pain helps to narrow down the diagnosis and guide treatment effectively.