Evaluating generalized back pain
In this video, you'll develop a rigorous system for identifying the source of acute back pain, learn why imaging is unlikely to tell you much, and discover a critical piece of information that patients often forget to tell you during history-taking.
Most lower back pain flare-ups are self-limited and go away on their own—but that doesn't mean you're off the hook! In this video, from our Neurology Masterclass: Managing Common Diseases course, you'll develop a rigorous system for identifying the source of acute back pain, learn why imaging is unlikely to tell you much, and discover a critical piece of information that patients often forget to tell you during history-taking.
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In this Medmastery lesson, we'll discuss what to do with patients presenting with generalized low back pain. Now, when we discuss generalized low back pain, we're referring to pain predominantly centered in the back, that doesn't fit the classical pattern of radiculopathy, or neurogenic claudication.
The back is a complex machine consisting of an array of components, that allow it to serve multiple functions, and withstand various external demands and forces. Consider that at each spinal level, there's an intricate arrangement of numerous muscles, and their attachments, ligaments, facet joints, vertebral bodies, discs, fascial planes, bony processes, a spinal cord, nerve roots, vasculature, and more.
Also consider that the human spine undergoes a relentless degenerative process through the years, starting at about age 16. And essentially, any component of the back is susceptible to pathological and, or inflammatory conditions that may cause pain directly, or by affecting other components.
Finally, consider that the back tends to act in a stereotypical manner when it senses irritation, inflammation and, or instability. It tends to tighten up the supporting muscles to act as an internal brace against undue movement in the region. These chronically contracting muscles themselves then start to ache, and generate their own pain, setting up a cycle of pain, spasm, pain.
It can be rather difficult to break out of this cycle without addressing or eliminating the original pain generator, that is the source of the pain. So the back can become painful for any number of reasons, and yet manifests itself principally as generalized muscle pain. The original pain generator may be next to impossible to identify.
Furthermore, imaging generally reveals a host of degenerative abnormalities, all of which, or none of which could be acting as a primary pain generator. Thus, when you're confronted with a patient with acute generalized back pain, you have quite a challenge on your hands. 90 percent of the time, a definitive cause will never be determined.
However, the good news is that most acute back pain syndromes are self-limited, and will go away with time and, or some conservative management. When faced with a patient with generalized low back pain, start with a good history. Ask about precipitating factors and alleviating factors, that is factors that make the pain worse, or better.
Ask about onset and duration of symptoms and attempted treatments, including any history of spinal surgery. You'll be amazed at how many patients forget to tell you that they've had previous major spinal surgery. Make sure you grade the patient's pain for future reference. It's important to follow the trajectory of the syndrome, is it getting worse or is it getting better?
There are multiple pain scales out there for this. Many people use the Oswestry disability scale. Some employ a simple one to 10 rating scale. I tend to be more descriptive using the patient's own words to denote the degree of pain. Ask about associated neurological symptoms such as leg weakness, paraesthesias, imbalance, bowel and bladder dysfunction.
Always keep in the back of your mind the possibility of myelopathy or cauda equina syndrome. Ask about daily activities and occupational demands. For example, it should come as no surprise that a coal miner or a troop in a parachute regimen, should develop back pain. Remember to ask about red flags, that is, indicators of potentially more serious or urgent conditions.
Ask about a history of cancer, and related symptoms, recent trauma, infection, and high risk behaviors, osteoporosis, steroid use, progressive weakness, severe intractable pain and gait dysfunction. And always ask about bowel and bladder dysfunction. Definitive red flags necessitate early radiographic evaluation. Consider, but never assume that psychological factors might contribute to the symptoms.
After taking a history, it's important to perform a good physical, and neurological exam. You're kind of feeling around in the dark here, so you don't want to miss clues to what could be a pain generator, or to the possibility of some serious pathology. Include a good examination of the back. Look for localized tenderness in the spinous process, and the adjacent muscles.
Does palpation here reproduce the pain? Are the muscles super tight? Look at the skin itself. There might be signs of spina bifida, such as hemangiomas, lumps, tracks or hairy patches. Note the patients with severe persistent back pain often have burns on their back from over use of various heating pads and devices.
Have the patient go through a range of motion of their spine, that is, flexion, extension, rotation and lateral bending. Do any of these movements exacerbate the pain? Always evaluate for myelopathy. Look for hyperreflexia, clonus, increased muscle tone, sensory level on the trunk, gait disturbance, loss of proprioception, loss of balance, a positive Romberg, and more.
If the patient has no major findings on exam, do not feel that you have to jump straight into an MRI. Remember, most lower back pain flare ups will be self limited, that is, they're going to go away. Although discouraged by some experts, if you're in an acute care setting, and evaluating a patient with severe low back pain, a lateral flexion and extension set of x-rays is a reasonable evaluation to look for obvious bony lesions, evidence of trauma, severe spinal deformity, an abnormal movement of the spine. It also can be somewhat reassuring for the patient. An EMG nerve conduction velocity study is seldom of use. I would not recommend it.