Table 1. Red flags for potentially serious conditions

Possible fracture             Possible tumor or            Possible cauda equina
                              infection                    syndrome

From medical history

Major trauma, such as         Age over 50 or under 20.     Saddle anesthesia.
vehicle accident or fall
from height.                  History of cancer.           Recent onset of bladder
                                                           dysfunction, such as
Minor trauma or even          Constitutional symptoms,     urinary retention,
strenuous lifting (in older   such as recent fever or      increased frequency, or
or potentially osteoporotic   chills or unexplained        overflow incontinence.
patient).                     weight loss.
                                                           Severe or progresive
                              Risk factors for spinal      neurologic deficit in the
                              infection: recent            lower extremity.
                              bacterial infection (e.g.,
                              urinary tract infection);
                              IV drug abuse; or immune
                              suppression (from
                              steroids, transplant, or
                              HIV).
                              Pain that worsens when
                              supine; severe nighttime
                              pain.

From physical examination

                                                           Unexpected laxity of the
                                                           anal sphincter.
                                                           Perianal/perineal sensory
                                                           loss.
                                                           Major motor weakness:
                                                           quadriceps (knee extension
                                                           weakness); ankle plantar
                                                           flexors, evertors, and
                                                           dorsiflexors (foot drop).