A small number of patients who present with low back pain will have an underlying medical disorder as the source of their pain. Patients who fail to respond to conservative management with controlled physical activity and nonnarcotic analgesics should have a thorough re-evaluation to detect possible sources of nonmechanical pain. Symptoms of fever, weight loss, recumbency pain, morning stiffness, acute severe pain, or colicky back pain represent specific entry points into the algorithm for diagnosis of back pain from underlying systemic illnesses. These patients will generally require a plain roentgenographic examination with subsequent scintography, MRI, CT, laboratory work, and biopsy as indicated by any positive findings during the diagnostic work-up. Therapy for individuals with nonmechanical low back pain is directed at the specific medical disorder that is the cause of their symptoms.
