From the Guidelines
Red flag features for back pain include severe trauma, unexplained weight loss, history of cancer, fever, immunosuppression, intravenous drug use, prolonged steroid use, age over 50 or under 20, pain that worsens when lying down or at night, bladder or bowel dysfunction, saddle anesthesia, and progressive neurological deficits, which may indicate serious underlying conditions such as cauda equina syndrome, malignancy, infection, or fracture, requiring immediate medical attention. These features are crucial in identifying patients who may require urgent evaluation and treatment to prevent serious complications, such as permanent neurological damage or death. According to the most recent study 1, the imaging study of choice in the evaluation of suspected cauda equina syndrome is MRI, which can accurately depict soft-tissue pathology, assess vertebral marrow, and assess the spinal canal patency. Some key red flag features to look out for include:
- Severe trauma
- Unexplained weight loss
- History of cancer
- Fever
- Immunocompromised state
- Intravenous drug use
- Prolonged steroid use
- Age over 50 or under 20
- Pain that worsens when lying down or at night
- Bladder or bowel dysfunction
- Saddle anesthesia
- Progressive neurological deficits, such as weakness or numbness in the legs. Patients presenting with any of these red flags should be promptly referred for further investigation, which may include imaging studies like MRI or CT scans, as recommended by the American College of Radiology 1. Early recognition of these warning signs is crucial, as delayed diagnosis of conditions like cauda equina syndrome can lead to permanent neurological damage, while infections or malignancies require timely intervention to prevent serious complications, as highlighted in the study by Bell et al 1.
From the Research
Red Flag Features for Back Pain
The following red flag features are associated with back pain:
- Recent trauma and an age of >50 years are associated with vertebral fracture 2
- Bowel and bladder dysfunction, and saddle sensory disturbance are associated with spinal cord or cauda equina compression, with likelihood ratios of 2.45 and 2.11 respectively 3
- History of cancer, unintentional weight loss, and pain at night or at rest are considered red flags for various underlying pathologies, including malignancy and fracture 4
- Red flags such as significant trauma, older age, and corticosteroid use may be useful in screening for vertebral fracture in primary care, with positive likelihood ratios ranging from 3.42 to 12.85 5
Limitations of Red Flags
- The absence of red flag responses does not meaningfully decrease the likelihood of a red flag diagnosis, with 64% of patients with spinal malignancy having no associated red flags 2
- The predictive value of red flags is limited, with many having high false positive rates and poor diagnostic accuracy 3, 5
- There is a lack of consensus between guidelines for which red flags to endorse, and evidence for the accuracy of recommended red flags is often lacking 4
Clinical Implications
- Clinicians should use caution when utilizing red flag questions as screening tools, and consider the potential for false positives and false negatives 2, 3
- A combination of red flags may be more informative than individual red flags in screening for vertebral fracture 5
- Further research is needed to identify appropriate sets of red flags and to improve the reporting of index and reference tests 5