From the Guidelines
Red flags of back pain that require immediate medical attention include severe pain, fever, unexplained weight loss, history of cancer, neurological symptoms, recent trauma, and age under 20 or over 50 years old. These warning signs may indicate serious underlying conditions such as infection, malignancy, spinal cord compression, or fractures. According to the most recent guideline update from the American College of Radiology in 2021 1, a focused history and physical examination are crucial in identifying these red flags. The guideline emphasizes the importance of reassurance, initial pain management, and consideration of physical therapies without routine imaging in patients with nonspecific low back pain. However, imaging is considered in patients who have had up to 6 weeks of medical management and physical therapy with little or no improvement, or in those presenting with red flags.
Some key red flags to watch out for include:
- Severe pain that worsens at night or when lying down
- Pain accompanied by fever
- Unexplained weight loss
- History of cancer
- Neurological symptoms like leg weakness, numbness, or bladder/bowel dysfunction (especially urinary retention or incontinence)
- Recent trauma, especially in older adults or those with osteoporosis
- Pain that doesn't improve with rest or worsens with time, particularly if it's been present for more than six weeks
- Age under 20 or over 50 years old
These red flags are significant because they help distinguish potentially dangerous conditions requiring urgent intervention from more common mechanical back pain that typically resolves with conservative management. As noted in a study published in the Annals of Internal Medicine in 2007 1, a history of cancer, unexplained weight loss, failure to improve after 1 month, and age older than 50 years are associated with a higher likelihood of cancer. Another study published in the same journal in 2007 1 highlights the importance of considering risk factors for cancer, infection, and vertebral compression fracture, as well as ankylosing spondylitis, in patients with back pain. However, the most recent and highest quality study 1 should be prioritized when making a definitive recommendation. If you experience any of these warning signs, seek medical evaluation promptly rather than attempting self-treatment.
From the Research
Red Flags for Back Pain
The following are some common red flags for back pain:
- Advanced age 2
- Neurological signs 2
- History of trauma 3, 2
- Malignancy 3, 2, 4
- Female gender 2
- Corticosteroids use 2
- Night pain 3, 2, 4
- Unintentional weight loss 3, 2, 4
- Bladder or bowel dysfunction 3, 2
- Loss of anal sphincter tone 2
- Saddle anaesthesia 2
- Constant pain 2
- Recent infection 3, 2, 5
- Family or personal history of heart or pulmonary diseases 2
- Dyspnoea 2
- Fever 2, 5
- Postprandial chest pain 2
- Typical reflux symptoms 2
- Haemoptysis 2
- Sweating 2, 5
- Pain radiated to upper limbs 2
- Hypotension 2
- Retrosternal pain 2
- Exertional pain 2
- Diaphoresis 2
- Tachycardia 2
Diagnostic Accuracy of Red Flags
The diagnostic accuracy of red flags as a self-contained screening tool is low 3, 2. However, the combination of multiple red flags may increase the probability of identifying serious pathologies 2. The absence of red flag responses does not meaningfully decrease the likelihood of a red flag diagnosis 3.
Prevalence of Red Flags
The majority of patients with low back pain report at least one red flag 4. The most prevalent red flag is foot weakness, while the least prevalent is unexplained weight loss 4. Pain intensity is a significant risk factor for the presence of at least one red flag 4.
Red Flags for Spinal Infection
Red flags for spinal infection include spinal pain, fever, and neurological dysfunction 5. Diabetes and IV drug use are also common determinants of spinal infection 5. MRI is the most commonly used radiological test for diagnosing spinal infection, and Staphylococcus aureus and Mycobacterium tuberculosis are the most common microorganisms detected in cases of spinal infection 5.