Table 1. Warning signs (“red flags”) for specific spinal causes of low back pain requiring urgent treatment^{*1, 2}.

Suspicion oftraumatic lesion	Suspicion oftumor	Suspicion ofinfection	Suspicion of radiculopathy, cauda equina syndrome
Severe trauma, e.g., car accident, fall from great height, sport accident Minor trauma (e.g., coughing, sneezing, heavy lifting) in an elderly patient or someone who may have osteoporosis Systemic steroid therapy	Advanced age (> 50 years) Prior history of tumor B symptoms: fever > 38°C, night sweats (multiple pyjama changes), unintentional weight loss (at least 10% of body weight in 6 months) Pain that increases in the supine position Intense pain at night	B symptoms Intense pain at night Prior history of bacterial infection History of spinal infiltration procedure IV drug abuse Immune suppression Underlying malignancy or other wasting disease Exotic travel Immigrant background	Segmental pain, paresthesia in area of pain, marked loss of strength (grade 3 or less) Cauda equina syndrome Sudden loss of bladder/bowel function (overflow bladder, sphincter weakness) Perianal/perineal hypesthesia Improvement of pain accompanied by complete loss of function of segmental muscle(s) (“death of nerve root”)

^*1modified from (e4); ^*2for further signs and symptoms and their treatment, see eTable 2