Sciatica can be a sign of a serious condition, in some cases. This can happen if the pain is accompanied by other symptoms, such as fever, chills, weight loss, night sweats, or signs of infection, such as redness, warmth, or pus in the lower back, buttock, or leg. This can indicate a condition such as spinal infection, spinal tumor, or spinal fracture. Sciatica can also be a sign of a serious condition if it affects the function or sensation of the bladder, bowel, sexual organs, or legs. This can indicate a condition such as cauda equina syndrome, which is a medical emergency that requires immediate attention. If you experience any of these symptoms, you should call 911 or seek emergency medical attention immediately.