Lower back pain is considered an emergency if it is accompanied by groin and buttock numbness or if the pain was caused by an accident, says PainScience.com. Lower back pain should be checked by a doctor if it has lasted for more than six weeks.
There are several signs that lower back pain can be the symptom of a more serious condition, according to Everyday Health. Back pain that affects the legs can be a sign of sciatica, when the sciatic nerve is compressed or injured, or it may be caused by a herniated disk. Also, if the patient feels weakness, tingling or numbness in the leg, this can be a sign of nerve damage. Lower back pain along with a fever and abdominal pain can signal serious conditions, such as an infection or appendicitis.
Another symptom to watch out for, combined with continuous lower back pain, is rapid weight loss, claims PainScience.com. This combination of symptoms could be a sign of cancer, such as bone cancer in the spine. However, a doctor usually waits for the occurrence of other symptoms associated with cancer before testing people with lower back pain. This prevents unnecessary testing that could cause alarm in situations that do not warrant it.