Diagnostic Triage

Neil Craton

LEARNING OBJECTIVES

After reading this chapter, you should be able to:

Define the “red flag” as it applies to the diagnostic triage of patients with spinal pain.
Define the “yellow flag” as it applies to the diagnostic triage of patients with spinal pain.
Define the “orange flag” as it applies to the diagnostic triage of patients with spinal pain.
List five red flags for the presence of cancer in patients with spinal pain.
List two red flags for the presence of infection in patients with spinal pain.
List three nonspinal causes of back pain.
Describe the role of plain radiography in the diagnostic triage algorithm for patients with spinal pain.
List the specific deep tendon reflex, myotome, dermatome, and dural stretch signs associated with radiculopathy from C5-T1 and L4-S1.
Describe the “Patient in Jeopardy” of developing chronic spinal pain associated with work loss and disability.
List 10 yellow flags for work loss and disability in patients with acute spinal pain.
Describe the limitations associated with the clinical identification of a specific tissue label for patients with simple backache.
Describe the sensitivity and specificity of magnetic resonance imaging in the diagnosis of patients with spinal pain.

“Listen to people; hearing someone’s burden can lighten it.

–NEIL CRATON

Measurable Objectives

A symptom or sign that indicates the patient may have a sinister condition like cancer and infection or a fracture.
A symptom or set of psychosocial circumstances that place the patient at greater risk for developing chronic pain, disability, and work loss.
A psychiatric condition that will have a potential detrimental effect on the patient with spinal pain.
Weight loss; lack of relief of pain with recumbency; pain that is progressive, persistent, and not related to activity; leg weakness; fevers; chills; anorexia; night sweats; age over 50; prior history of cancer; and smoking.
Pain that is not related to activity, fevers, chills, anorexia, night sweats, immune compromise, risk factors for HIV, urinary symptoms, and prior use of corticosteroids.
Renal disease, vascular disease, gynecologic problems, and gastrointestinal pathology.
X-ray is chiefly indicated for primary investigation of patients suspected of having sustained a fracture after significant trauma. Many abnormalities seen on x-ray are difficult to relate to the patient’s episode of spinal pain.
The three A’s of affective disturbance, addictions, and abuse. Psychosocial factors are more important than physical ones.
It is difficult to make a tissue-specific diagnosis on clinical grounds alone.
High sensitivity. Less specificity, as many magnetic resonance imaging (MRI) anomalies are not associated with pain or dysfunction.

Diagnostic Triage in Patients With Spinal Pain

The diagnosis and treatment of patients with spinal pain represent a unique blend of art and science. Many different paradigms have been developed to explain where back pain comes from and how to treat it. The treatment offered to patients is often based on tissue-specific, paradigm-specific diagnostic labels. The same patient may receive distinctly different diagnoses from different practitioners to explain the same episode of spinal pain. This is related to the art of diagnostic triage. Despite the use of differing diagnostic labels, clinicians from all paradigms are required to identify patients with serious underlying conditions responsible for the patient’s back pain. This is mandatory for all practitioners and represents the science of diagnostic triage. This chapter outlines a process for the evaluation of back pain, which can be used to place patients into one of the following categories:

Possible serious or ominous pathology
Nonspinal pathology (gynecologic, renal, gastrointestinal, and vascular)
Problems associated with radiculopathy and potential neurologic deficits
Benign spinal problems with no neurologic deficit (simple backache, mechanical back pain, or nonspecific back pain)

The scientific limitations in the art of making a tissue-specific diagnosis for patients with lumbar pain will also be reviewed.

Most clinicians who specialize in the treatment of spinal disorders pride themselves on the ability to conduct a comprehensive physical assessment of a patient with spinal pain. The identification of a pain generator, biomechanical anomalies, and other culprits comprises a fundamental part of the diagnostic process for many clinicians. However, the assessment of patients with acute spinal pain does not require the clinician to make a tissue-specific diagnosis. Even though a diagnosis might be made using elegant clinical assessments or invasive techniques, this is often only of academic interest, as most patients will improve regardless of diagnosis or management.¹^,²^,³ This, combined with the fact that many common spinal conditions have no pathognomonic, reliable, or validated physical manifestations, limits the utility of a tissue-specific diagnosis in the triage of patients with spinal pain.⁴^,⁵^,⁶^,⁷^,⁸^,⁹^,¹⁰^,¹¹^,¹²^,¹³ Therefore, the diagnostic algorithm for patients with spinal pain focuses initially on the exclusion of serious pathology. Patients with spinal pain that may be caused by malignancy, infections, fractures, or cauda equina syndrome (CES) may require emergent triage to tertiary care institutions for definitive investigation and management. The diagnostic triage process must also exclude nonspinal pathology such as renal, abdominal, vascular, and gynecologic
diseases. After ruling out serious or nonspinal pathology, the clinician can then conduct a musculoskeletal assessment to exclude spinal pathology and should distinguish a nerve root problem from simple backache.¹⁴

The diagnostic triage process does not end with the determination of whether or not the patient has a serious or radicular problem. The biopsychosocial model of spine care emphasizes that emotional, psychosocial, and psychiatric factors can strongly influence the prognosis of patients with back pain. The pandemic of spine pain-related disability and worklessness testifies to the importance of preventing chronicity in people with spine pain, and that psychosocial factors strongly influence the prognosis of organic spinal pathology.

The process of assessing patients with spinal pain has been the subject of substantial scholarship. Guidelines have been published throughout the world to assist clinicians in making evidence-based, cost-effective decisions to deal with the back and neck pain population.¹^,³^,¹⁴^,¹⁵^,¹⁶^,¹⁷^,¹⁸ Multidisciplinary diagnostic algorithms outlining the consensus opinion of researchers have been published, with recommendations for the investigation and clinical treatment of patients with spinal pain.¹^,³^,¹⁴^,¹⁵^,¹⁶^,¹⁷^,¹⁸^,¹⁹

The Red Flag

The red flag can be defined as a clinical symptom or sign that may indicate serious or ominous pathology as the etiology of the patient’s spinal pain.¹^,²^,¹⁵ The identification of a red flag should trigger action steps that are individualized to each patient. The red flag may prompt advanced imaging, serologic investigations, additional patient education, urgent referral, or expectant observation.

The key tools used in determining which patients may have a serious underlying condition presenting as spinal pain are history and physical examination. The identification of the “red flag” from a detailed history is the most important part of the diagnostic triage process. Most red flags are symptoms and can be elicited without a physical examination. Physical examination is typically less valuable in determining which patients have serious problems like cancer.¹^,²^,¹⁵ Current evidence shows that no particular clinical constellation of physical signs allows a valid or reliable diagnosis to be made in anatomic or pathologic terms (aside from radiculopathy).¹

The vast majority of patients with spinal pain will not have sinister pathology as the source of their spinal pain.¹^,²^,¹⁵^,²⁰ Health care practitioners who see a high volume of spinal pain patients will generally see benign mechanical low back pain that can be referred to as simple backache or nonspecific back pain.²^,¹⁴^,¹⁹^,²⁰ Still, the clinician needs to maintain a high level of vigilance to avoid missing sinister pathology among their many patients with benign spinal pain.

Serious or Ominous Conditions

The most serious conditions that may cause spinal pain include cancer, infections, CES, unstable vertebral fractures, intra-abdominal vascular accidents, or a ruptured viscus. The triage process for these conditions should begin with the patient interview, focusing on symptoms suggestive of this type of pathology.

Malignancy The probability of a cancer patient presenting to a primary care practitioner with back pain is less than 1%.¹^,²^,²¹ Most patients with cancer-related back pain are elderly. The most common presenting complaint of patients with spinal neoplasia is back pain.²² This coupled with the fact that patients with spinal neoplasia will often report an episode of trauma at the onset of their pain highlights the requirement for a thorough review of systems on each and every spinal pain patient.

Back pain in patients with cancer may be caused by inflammatory mediators, tumor stretching the periosteum of the vertebral body, or direct neural pressure.²³ Symptoms that are suggestive of spinal malignancy are pain that is persistent, progressive, and worse at night. Patients with benign mechanical back pain tend to get relief with recumbency.²² Patients with low back pain and weakness of the lower extremities must also be considered to be at increased risk for harboring a spinal tumor. Up to 40% of people with primary neoplasms of the spine present with lower extremity weakness, whereas 30% of patients with metastatic lesions will present with a neural compression syndrome.²⁴^,²⁵ Deyo and Diehl showed that age over 50, prior cancer history, unexplained weight loss, pain lasting more than 1 month, and no improvement with initial therapy are symptoms significantly associated with back pain due to cancer.²¹ In their large, prospective study in a primary care setting, a history of cancer (positive likelihood ratio, 14.7), unexplained weight loss (positive likelihood ratio, 2.7), failure to improve after 1 month (positive likelihood ratio, 3.0), and age older than 50 (positive likelihood ratio, 2.7) were each associated with a higher likelihood for cancer.²^,²¹ The probability of cancer in patients presenting with back pain increased from approximately 0.7% to 9% in patients with a history of cancer other than most skin cancers. In patients with any one of the other three risk factors, the likelihood of cancer only increases to approximately 1.2%.²

Other worrisome symptoms for malignancy include anorexia, fevers, chills, rigors, and night sweats. The presence of these red flags requires the clinician to undertake diagnostic tests to rule out a malignancy. MRI is the most sensitive investigative tool for this purpose.¹⁹

The majority of tumors that affect the lumbar spine are metastatic. Metastatic disease accounts for 40 times as many cases of spinal neoplasia as all other forms of bone cancer combined.²² Between 5% and 10% of all cancer patients develop spinal metastases during the course of their disease.²³ Therefore, ascertaining risk factors for malignancy is required in the diagnostic triage process. In females, the most common tumors to metastasize to the vertebrae are from the breast and lung.²⁵ A prior personal history of breast cancer or a personal history of smoking would be considered an important risk factor for these malignancies. In males, the most common tumors to metastasize to the vertebrae are from the prostate and lung. Advancing age, symptoms of prostatism such as urinary hesitancy, nocturia, and decreasing caliber of the urinary stream should prompt consideration of prostate disease. A rectal examination including assessment of the volume and consistency of the prostate will indicate which patients should be sent for urologic consultation. Serologic investigations including serum calcium, alkaline phosphatase, and an acid phosphatase should be performed if metastatic prostate cancer is suspected. Prostate-specific antigen levels in blood can also be a useful screening test for prostatic malignancy.

Aside from the imaging tests (see later), simple laboratory tests including a complete blood count (CBC) and erythrocyte sedimentation rate (ESR) can aid the diagnostic process when there is a suspicion of infection or tumor being the etiologies for a patient’s spinal pain.²⁶

Infections of the Spine The probability of a patient presenting to a primary health care practitioner with back pain having an infection as the cause is less than 0.01%.¹^,²⁷ Features predicting the presence of vertebral infection have not been well studied. The incidence of central nervous system infections has risen largely because of the epidemic of acquired immunodeficiency syndrome. As a consequence, spinal infections have also increased.²⁸ Therefore, the diagnostic triage process must include appropriate questions regarding the risk factors for human immunodeficiency virus (HIV) acquisition. Poverty, intravenous drug use, anal intercourse, multiple sexual partners, and hemophilia are important risk factors for HIV infection.

The most common symptoms of spinal infection include malaise and back pain.²⁸ The most sensitive historical factors for the identification of spinal osteomyelitis in a patient with back pain are history of intravenous drug use, prior urinary tract infection, or skin infection.²⁹ Symptoms more specific for a spinal infection, or a nonspinal infection that is responsible for referred spinal pain, may also include fevers, chills, rigors, and night sweats. Individuals with these symptoms need to be evaluated for osteomyelitis, discitis, or an epidural abscess.¹^,²⁶ Compromised hosts, such as diabetics, intravenous drug users, and the chronically ill, are particularly susceptible to spinal infections. Prior spinal surgery should also raise the index of suspicion regarding an infectious process. Patients who have had prior chemotherapy, radiotherapy or have used corticosteroids or other immunosuppressant drugs should be considered at increased risk for having a spinal infection when they present with back pain. Dysuria, urinary frequency, urinary urgency, and pain radiating to the groin increase the likelihood of a urinary tract infection.

There are few clinical signs that are both sensitive and specific for the identification of a spinal infection. Fever, vertebral tenderness, and very limited spinal range of motion may not only suggest the possibility of a spinal infection, but may also be present in other causes of spinal pain.¹⁵^,²⁸ The urinalysis is a simple, noninvasive test that can be used to screen for hematuria or pyuria in the presence of urinary tract pathology. Subsequent midstream urine assessment for culture and sensitivity can confirm the presence of bacterial pathogens and guide subsequent antimicrobial treatment.

The evaluation of a patient suspected of having an infection as the source of their spinal pain should include a CBC and an ESR. The ESR is a very sensitive tool for infection, although it is not specific, and may be elevated in other systemic conditions like spondyloarthropathies and rheumatologic conditions.¹^,²⁶ Culture of the appropriate body fluids should be performed in association with advanced imaging. The nucleotide bone scan was the primary investigation for suspected spinal infection, but this has largely been replaced by MRI that is both sensitive and specific.¹^,²⁶

Nussbaum et al retrospectively analyzed 40 cases of spinal epidural abscess.²⁶ Medical records and radiologic images were reviewed. Sixteen patients had used intravenous drugs and six had undergone spinal interventions. Twelve patients were misdiagnosed in various emergency rooms or clinics and discharged. Localized back pain, fever, and neurologic deficit were the most common clinical manifestations. ESR was elevated uniformly when measured (21 cases). MRI was diagnostic in 23 of 24 instances. The authors documented that the highly variable presentation of spinal epidural abscess may confuse the diagnosis and delay surgical intervention. Back pain in a febrile patient
who has had a recent spinal intervention or used IV drugs warrants ESR measurement and a high level of suspicion for an epidural abscess. The presence of ESR elevation or evidence of spinal cord compression on physical examination is indication for immediate MRI examination with or without contrast enhancement.²⁶

A recent, interesting, and controversial development has been the potential role of chronic low-grade infection in patients with chronic back pain.³⁰ Urquhart et al reviewed the literature and found nine studies that examined the presence of bacteria in spinal disc material. All of these studies identified bacteria. Propionibacterium acnes was the most prevalent bacteria, being present in seven of the nine studies. They concluded that there is moderate evidence for a cause-effect relationship between the presence of bacteria and low back pain with disc herniation and Modic type 1 change. Further work is needed to determine whether the presence of these organisms is a result of contamination or represents low-grade infection of the spine, which contributes to chronic low back pain.³⁰ There is little in the literature to guide the diagnostic triage process with regard to this potential etiologic factor.

Spinal Fractures Significant trauma is the most important historical factor that would lead the clinician to suspect a fracture in a patient with acute spinal pain. The age of the patient will influence the magnitude of trauma required to cause a spinal fracture, as the frail elderly require significantly less force to fracture a vertebra. In the general population, fractures presenting as back pain occur only in patients with a history of major trauma.¹^,²^,³¹ A fall from a significant height or a high-velocity motor vehicle accident associated with acute low back or neck pain should prompt the clinician to consider plain radiographic imaging to detect a fracture.³² In older individuals or those with other constitutional difficulties, simple heavy lifting or a minor fall should raise the index of suspicion of a spinal fracture.¹⁵ Increasing age and osteoporosis are definite risk factors for spinal fractures with minimal identifiable trauma, and back pain after a sneeze is enough to warrant radiographs in a susceptible elderly patient.

A patient with spinal pain after trauma needs to be considered to have an unstable spinal injury until proven otherwise. Any neurologic symptoms or alterations in the patient’s level of consciousness mandate that the patient be immobilized and emergently triaged for spinal imaging. Hard collar immobilization for cervical injuries and a backboard with pelvic and cervicothoracic immobilization should be used for more caudal injuries. Practitioners who cover athletic events with a high risk of spinal trauma such as football and hockey need to rehearse the management of an athlete with a suspected spinal fracture. Any athlete who has bone tenderness, diminished range of motion, or even transient neurologic signs needs to be managed with great caution.

There are several evidence-based algorithms for the use of plain radiography in the identification of spinal fractures after cervical spine injury.³² The Canadian C-Spine Rules (CCR) use factors that differentiate between high-risk situations and clinical factors that indicate a low risk. High-risk criteria include age over 65, a dangerous mechanism of injury, and/or the presence of paresthesia in the extremities. Low-risk factors that mitigate the presence of a spinal fracture include the ability to ambulate after the injury, a lowrisk mechanism like a rear-end motor vehicle collision, and the absence of midline spinal tenderness. The CCR also use the criterion of the ability to actively rotate the neck 45 degrees as indicative of a low risk of spinal fracture. The Nexus Criteria state that cervical spine radiography is indicated for patients with trauma unless they meet all of the following criteria:

No posterior midline cervical spine tenderness
No evidence of intoxication
A normal level of alertness
No focal neurologic deficit
No painful distracting injuries

A large multicenter study has also shown that the CCR are more specific than the Nexus Criteria and are consequently likely to have a greater effect in reducing the unnecessary use of radiography and the need for costly and time-consuming spinal immobilization. The Nexus Criteria have also demonstrated a lower sensitivity, potentially missing 1 in 10 important injuries. The CCR have proven to be more sensitive in the diagnosis of cervical spine fractures than the Nexus guidelines.³² The CCR identified 161 of 162 fractures in patients in whom the range of motion component was evaluated. A sensitivity of 52% has been demonstrated for this algorithm. These findings raise questions about the safety and efficiency of applying the Nexus Criteria in clinical practice (Table 6.1).

The triage of a patient with trauma and back pain should include plain radiography as the initial investigation. Screening for spinal injuries where instability is a possibility is typically performed with lateral plain radiographs. The spine must be evaluated for evidence of soft-tissue swelling and alignment. The lateral
radiograph can be performed while the patient is in the appropriate immobilizing devices if a suspected unstable spine fracture is being evaluated.³²^,³³ Focal kyphosis in the lumbar spine or other local alignment anomalies can be an important sign of injury. The lateral radiograph must include all of the spinal elements that may be at risk. Imaging of the lower cervical spine and the cervicothoracic junction is a frequent problem because of the overlapping bony anatomy in this area that obscures this region. The lateral radiograph alone is insufficient to rule out fracture and is the starting point in the triage of a patient with a potential spinal fracture. If the lateral film is normal, other views can be obtained. If plain radiographs are normal and the index of suspicion is high enough, either computed tomography (CT) or MRI scan should be performed. In a patient with persisting pain after trauma, with an initial normal x-ray, the investigation could be repeated in 10 to 14 days. Bone scan offers another sensitive modality for occult spinal fracture.

When a fracture is identified on plain film, CT can be valuable in demonstrating the relationship of the fracture fragments to the spinal canal.³³ CT is also of particular value for imaging the posterior spinal elements. MRI can also elucidate injury to the spinal cord or surrounding ligamentous structures.³⁴ In a group of patients in whom physical findings indicated the potential for spine injury or radiographic findings were inconclusive, MRI can identify meaningful pathology. A recent series studied patients who did not appear to harbor disruption of spinal integrity on the basis of a routine x-ray film. None had clinically obvious injury. Of the 174 patients, 62 (36%) had soft-tissue abnormalities identified by MRI. Most of the anomalies were related to the intervertebral disc, which may not have been related to the trauma. Isolated ligamentous injury was observed in 35 patients (8 with ventral and dorsal ligamentous injury, 5 with ventral ligamentous injury alone, and 22 with dorsal ligamentous injury alone). One patient underwent a surgical fusion procedure, 35 patients (including the one treated surgically) were placed in a cervical collar for at least 1 month, and 27 patients were placed in a thermoplastic Minerva jacket for at least 2 months. All had a satisfactory outcome without evidence of instability. This study indicates that even evidence-based guidelines are not perfect.

Table 6.1 Canadian C-Spine Rules

For patients with trauma who are alert (as indicated by a score of 15 on the Glasgow Coma Scale) and in stable condition and in whom cervical spine injury is a concern, the determination of risk factors guides the use of cervical spine radiography. A dangerous mechanism is considered to be a fall from an elevation of ≥3 feet or 5 stairs; an axial load to the head (e.g., diving); a motor vehicle collision at high speed (>53 km per hour) or with rollover or ejection; a collision involving a motorized recreational vehicle; or a bicycle collision. A simple rear-end motor vehicle collision excludes being pushed into oncoming traffic, being hit by a bus or a large truck, a rollover, and being hit by a high-speed vehicle.

Any high-risk factor that mandates radiography?

Age ≥65 years or dangerous mechanism or paresthesias in extremities?

Any low-risk factor that allows safe assessment of range of motion?

Simple rear-end motor vehicle collision or sitting position in the emergency department or ambulatory at any time or delayed (not immediate) onset of neck pain or absence of midline cervical spine tenderness.

Able to rotate neck actively 45 degrees left and right?

From Stiell IG, Clement CM, McKnight RD, et al. The Canadian C-Spine Rule versus the NEXUS low-risk criteria in patients with trauma. N Engl J Med. 2003;349:2510-2518.

Other Red Flags

Cauda Equina Syndrome CES is a relatively rare condition comprising around 2% to 6% of lumbar disc operations.³⁵ It is usually a consequence of a large central lumbar disc herniation, but can be due to smaller prolapses in the presence of spinal stenosis. Less common causes include epidural hematoma or abscess, infections, primary and metastatic neoplasms, trauma, surgery, prolapse after manipulation, chemonucleolysis, and spinal anesthesia, and it has been reported in patients with ankylosing spondylitis, gunshot wounds, and even resulting from constipation.³⁵ Patients who manifest incontinence of stool or urine need to be considered as having CES until proven otherwise. Associated symptoms include bilateral leg pain or paresthesia, urinary urgency, and sexual dysfunction. Urinary retention is found in a high number of cases and is the most worrisome red flag.³⁵ Physical signs that may accompany the historical red flags could include a perineal sensory disturbance often referred to as saddle anesthesia and decreased rectal tone. When the syndrome is incomplete, the patient has urinary difficulties of neurogenic origin including altered urinary sensation, loss of desire to void, poor urinary stream, and the need to strain in order to micturate. Saddle and genital sensory deficit is often unilateral or partial and trigone sensation should be present. The complete syndrome is characterized by
painless urinary retention and overflow incontinence when the bladder is no longer under volitional control. There is usually extensive or complete saddle and genital sensory deficit with deficient trigone sensation. Bilateral severe sciatica should always ring alarm bells for this syndrome.³⁵

CES can have devastating, long-lasting neurologic consequences, although it is well established that the outcome for patients with incomplete CES at the time of surgery is generally favorable. Those who manifest urinary retention when the compression is surgically relieved have a poorer prognosis.³⁵

The timing of surgical decompression remains important.³⁶ It is believed that emergent surgical decompression of the cauda equina can prevent a neuropraxia from progressing to a more permanent neurologic deficit. Therefore, emergent advanced imaging with CT or MRI is necessary in this population. Unfortunately, evidence indicates that the time to surgical decompression may not influence patient outcomes.³⁶ Leg weakness persists in a significant number of patients at follow-up. Bowel dysfunction at presentation was associated with sexual problems at follow-up. Patients who have had CES often do not return to a normal function.

Progressive Neurologic Loss The presence of progressive neurologic loss is another harbinger of sinister spinal pathology.²² Most spinal clinicians are quite comfortable following patients with unilateral lower motor neuron abnormalities affecting a single nerve root. These findings are often associated with compressive disc lesions or chemical radiculitis secondary to disc anomalies and represent most radiculopathies. Published guidelines state that such patients do not require advanced spinal imaging or referral if they improve with the initial clinical interventions and time.³^,¹⁵^,³⁷ In patients with back and leg pain, the history alone of pain in a typical lumbar nerve root distribution, has a fairly high sensitivity for a herniated disc. More than 90% of symptomatic lumbar disc herniations occur at the L4/L5 and L5/S1 levels. A focused examination that includes straight leg raise testing and a neurologic examination that includes evaluation of knee strength and reflexes (L4 nerve root), great toe dorsiflexion strength (L5 nerve root), foot plantar flexion and ankle reflexes (S1 nerve root), and distribution of sensory symptoms should be done to assess the presence and severity of nerve root dysfunction. A positive result on the straight leg raise test, defined as reproduction of the patient’s sciatica between 30 and 70 degrees of leg elevation, has a sensitivity of close to 90%, but only modest specificity of around 25% for diagnosing a herniated disc. The deficits in most cases of lumbar radiculopathy involve only one side of the body and one nerve root level.

When patients develop progressive loss of strength, sensation, altered reflexes, or the neurologic loss covers more than one nerve root or is bilateral, urgent imaging for an expanding space-occupying lesion is indicated. MRI is the most sensitive tool for the investigation of this group of patients.¹⁹^,²³^,³⁷ Individuals with upper motor neuron findings of hyperreflexia, increasing muscle tone, upgoing toes, and clonus also require urgent central nervous system imaging to rule out compressive myelopathy or other central nervous system anomalies. Given the termination of the spinal cord at L1, patients with myelopathy will require imaging of levels more cephalad than the lumbar spine, including both the cervical and thoracic spine, and sometimes even the brain. Patients manifesting these signs need to have a definitive diagnosis reached as soon as possible. The findings of myelopathy are always red flags.

Nonspinal Causes of Back Pain The most common systemic conditions presenting with spinal pain are the spondyloarthropathies. Patients with spondyloarthropathies or other inflammatory conditions need to be identified as early as possible in the diagnostic process, as they often require specific investigations and pharmacologic therapy in addition to other therapies. Psoriatic rashes are a clue to the presence of psoriatic spondyloarthropathy. Symptoms of diarrhea or inflammatory bowel disease also should prompt the clinician to consider Reiter disease and ankylosing spondylitis. Ankylosing spondylitis is characterized by morning stiffness, improvement with exercise, onset under 40 years, alternating buttock pain, awakening due to back pain during the second part of the night only, and a pain duration of more than 3 months. Recurring tendinopathies or enthesitis should also increase the index of suspicion of this class of disorder. Initial blood work for the evaluation of a patient with a suspected rheumatologic condition or spondyloarthropathy should include a CBC, an ESR, a rheumatoid factor, an antinuclear antibody screen, and a uric acid level. Concern regarding ankylosing spondylitis should prompt an HLA B27 histocompatibility screen. In this group of disorders, prompt referral to a rheumatologist may allow the initiation of newer medical therapies that prevent joint damage. Clinicians should be aware that criteria for diagnosing early ankylosing spondylitis (before the development of radiographic abnormalities) are evolving.³

Diagnostic triage should distinguish patients with other nonspinal causes of pain felt in the vertebral area. Pain emanating from intra-abdominal and retroperitoneal structures will frequently require non-primary care investigation and management.

Various intra-abdominal conditions can present with spinal pain. The most sinister would be a ruptured abdominal aortic aneurysm. These patients may have no specific features early in their presentation. A history of vascular disease or the presence of cardiovascular and atherosclerotic risk factors warrants assessment for this condition. Careful abdominal palpation should reveal a pulsatile mass, which may be tender. Any abdominal guarding, rebound tenderness, or vital sign anomaly would prompt emergent referral to a tertiary care institution via ambulance. En route to hospital, large-bore intravenous access will be established. At the hospital, definitive imaging will include CT, MRI, or ultrasound.

There are many other intra-abdominal conditions that can refer pain to the back. Fortunately, all of these are rare sources of back pain. Peptic ulcer disease (with or without perforation), pancreatitis, biliary colic, endometriosis, pelvic inflammatory disease, ectopic pregnancy, and ovarian cysts can all cause back pain. Most of these conditions would be missed if the clinician fails to lay a hand on the patient’s belly or to consider gynecologic problems in female patients. Other factors such as symptoms unrelated to activity, pain that is worse when lying down, and presence of gastrointestinal or genitourinary symptoms can be helpful in suggesting underlying visceral or systemic etiologies.

Simple Backache Versus Nerve Root Problems

The terms “simple backache,” “mechanical back pain,” and “nonspecific low back pain” can be used to describe back pain that is musculoskeletal in origin. Pain receptors are present in bone, zygapophyseal joint (z-joint), muscle, connective tissue, periosteum, the outer third of the intervertebral disc, and perivascular tissue. Pain receptors can be activated by mechanical strain or dysfunction, nociceptive metabolites, or inflammation. The term “simple backache” implies that the nerve roots and spinal cord are not compromised, and that there is no evidence of sinister or nonspinal pathology. Simple backache can be very painful and can refer pain to the leg, hip, or thigh, but generally not below the knee.¹⁴ This group of patients can receive a wide array of different diagnostic labels depending on the training of the health care practitioner they visit. Patients with simple backache and no red flags do not require any diagnostic investigations in the first month of symptoms (Fig. 6.1).

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