In dermatomyositis, what finding is typically intact despite muscle weakness?

In dermatomyositis, a condition characterized by muscle weakness and a distinctive rash, the reflexes remain intact despite the muscle weakness. This condition primarily involves the inflammatory destruction of muscle fibers, which leads to muscle weakness. However, the lower motor neurons, which are responsible for reflexes, are typically not affected in dermatomyositis.

The preservation of reflexes indicates that the pathways involved in eliciting the reflex response—such as the sensory nerve fibers, spinal cord synapses, and motor neurons—remain functional. Therefore, even though patients may experience significant muscle weakness and fatigue, their deep tendon reflexes usually appear normal upon examination.

Other choices, such as temperature sensation, muscle strength, and visual acuity, are not preserved in the same way. Muscle strength is compromised due to the proximal muscle weakness inherent in the condition. Temperature sensation can be affected depending on the extent and involvement of the skin, and visual acuity is unrelated to the muscular and dermal implications of dermatomyositis, as it pertains to the eye and not to muscle function. Thus, the presence of intact reflexes is a key clinical feature that distinguishes dermatomyositis from other conditions that may cause muscle weakness.