Low back pain (LBP) typically results from relatively “benign” causes, meaning it’s usually safe to wait and try conservative / non-emergency care first. However, there are a handful of times when prompt medical emergency management is appropriate, and it’s important that everyone is aware of these uncommon but dangerous and sometimes deadly causes of LBP, hence the purpose of this article.

“Red flags” trace back to the 1980s and 1990s, so this is not a “new” topic. In fact, guidelines for the care of LBP that have been published around the world ALL commonly state the anyone exhibiting these “red flags” needs to be promptly diagnosed and referred for emergent care. The common conditions cited in these guidelines include (but are not limited to): 1) Cancer, 2) Cauda equine syndrome, 3) Infection,  4) Fracture. The patient’s history can sometimes uncover suspicion of these four conditions BETTER than a routine physical examination, though a definitive diagnosis is usually made only after special diagnostic tests have been completed including (but not limited to) imaging (x-ray, MRI, CT, PET scans), blood tests, bone scans, and more.

1) Cancer: a) Past history of cancer. b) Unexplained weight loss (>10 kg within 6 months). c) Age over 50 or under age 18. d) Failure to respond to usual care (therapy). e) Pain that persists for four to six weeks. f) Night pain or pain at rest.

2) Infection: a) Persistent fever (>100.4º F). b) Current/recent URI (upper respiratory tract infection like pneumonia) or UTI (urinary tract or kidney infection). b) History of intravenous drug abuse. c) Severe back pain. d) Lumbar spine surgery within the past year. e) Recent bacterial infection (cellulitis or persistent wound – e.g., a decubitus ulcer or “pressure sore” in the low back region). f) Immunocompromised states such as those caused by systemic corticosteroids, organ transplant medications, diabetes mellitus, human immunodeficiency virus (HIV).

3) Cauda Equina Syndrome: a) Urinary incontinence or retention. b) Saddle anesthesia. c) Anal sphincter tone decrease or fecal incontinence. d) Bilateral lower extremity weakness or numbness. e) Progressive neurologic deficit or loss – major muscle weakness or sensory deficit.

4) Fracture: a) Prolonged corticosteroid use. b) Age >70. c) History of Osteoporosis (poor bone density). d) Mild trauma over age 50. e) Major trauma at any age (such as a fall).

Another red flag is an Abdominal Aortic Aneurism. Signs include: a) Abdominal pulsations. b) Hardening of the arteries (atherosclerotic vascular disease). c) Pain at rest or night time pain. d) Age >60.