What red flag symptom is associated with spinal abscess in patients with low back pain?

Fever is a red flag symptom associated with spinal abscess in patients experiencing low back pain due to its association with infection. The presence of fever often indicates an inflammatory or infectious process within the body. In the case of a spinal abscess, the infection leads to the accumulation of pus within the spinal tissues, which can result in systemic symptoms such as fever, chills, and malaise.

When evaluating a patient with low back pain, a fever can prompt clinical suspicion of serious underlying conditions, including infections like spinal abscesses, meningitis, or osteomyelitis. These conditions necessitate prompt diagnosis and treatment, as they can lead to severe complications if left unchecked.

The other symptoms listed, such as loss of sensation, tingling in extremities, or muscle spasms, may be relevant in the broader context of neurological issues affecting the spine, but fever is a more direct indicator of a potential infectious process that could point specifically towards a spinal abscess. This is why fever is considered a critical red flag in this scenario.