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COVER ARTICLE/CME Urgent Care 2(6):18, 2007 Urgent care physicians repeatedly omitted the nonmusculoskeletal origin of this patient’s pain from the differential. Would you have made the same mistake? A 25-year-old man presents to your urgent care center with a chief complaint of low back pain. He states that the pain began as “tail bone pain” about four months ago. Since then, the affected area has expanded and the pain now radiates to his groin. He reports no precipitating factors such as trauma, repetitive movement syndrome, or work- or exercise-related injury. Rest neither aggravates nor relieves the pain. A review of his chart reveals multiple visits over the previous four months, with the same chief complaint of low back pain. Each time, his vital signs were within normal limits and the musculoskeletal and neurologic exams were unremarkable. An x-ray of the spine taken on the first visit was also unremarkable, but the patient has lost nine pounds since that visit. He was repeatedly diagnosed with muscle sprain/recurrent low back pain and given a prescription for an oral nonsteroidal anti-inflammatory drug or an intramuscular injection of toradol. He has also been through multiple courses of physical therapy and treatments by a chiropractor. The patient states that nothing has helped relieve his symptoms. He appears to be in distress and generally does not look well. What do you do for this patient? What is the differential diagnosis? What diagnostic studies do you order? What are your preconceived ideas about this patient? What simple exams were not performed previously? In this case, the patient was referred to a family medicine physician, who, during the initial physical examination, found testicular masses. This was the first time in the course of this patient’s complaints that a testicular exam was performed. Magnetic resonance imaging (MRI) was ordered. It revealed tumors in both testicles as well as spinal metastases at the level of the first and second lumbar vertebrae. The final diagnosis was stage 3 testicular choriocarcinoma. PRECONCEIVED NOTIONS What is your first thought when you pick up a chart and the chief complaint is back pain? Drug seeker? Wants some time off work? Is this patient legitimate? Regardless of the chief complaint or what the patient looks like, we must approach each patient with the same professional attitude and objective clinical judgment. In the case study above, because the urgent care physicians’ differential diagnosis was too narrow, the physical exam was not exhaustive and the medical history did not cover nonmusculoskeletal causes. This resulted in a lengthy delay in establishing the correct diagnosis and initiating appropriate treatment. Every health care professional knows how to obtain a complete history and perform a thorough physical examination. Unfortunately, this takes time, and we often have too many patients to spend as much as an hour with each one. Therefore, it is important to be aware of the broad differential diagnosis of low back pain, to ask the relevant questions, and to perform the appropriate exams. Most adults will experience low back pain during their lifetime. About 90% of these patients have back pain secondary to degenerative changes or minor musculoskeletal trauma and will improve with conservative treatment. However, back pain is the presenting symptom in 90% of patients with spinal tumors. Knowing what to look for—particularly in the case of nonmusculoskeletal causes of back pain—can potentially result in significantly decreased morbidity and mortality. KEY HISTORY-TAKING POINTS Whether the patient is presenting to you with a new complaint or is presenting with the same complaint for the tenth time, a systematic approach to history-taking will allow you to be concise yet thorough. You may ask one key question that was not asked in any of the previous visits. You may also prompt the patient to mention something that may have seemed insignificant to him or her. The box below outlines one method of describing the history of a present illness. Using the acronym “OLD CARTS” will help elicit important details regarding the patient’s chief complaint of low back pain.
The patient’s age is an important factor in developing the differential diagnosis. An age of less than 20 years or more than 50 years should raise the suspicion of more serious pathology. In the younger population, tumors must be considered. This is also the case in the older patient with new-onset back pain without an acute injury, as in osteoporosis. If initial conservative treatment fails, a thorough evaluation of these patients should then include radiographs of the spine, a complete blood count (CBC), and an erythrocyte sedimentation rate (ESR). Besides age, there are many other red flags that should alert you to the possibility of a more serious cause underlying low back pain (see box below).
The patient’s past medical and surgical histories are also important to consider. This is often difficult to elicit from the patient. It is best to begin with open-ended questions and then move on to more focused questions based on the patient’s responses. Try to obtain information regarding childhood and adult illnesses, immunizations, injuries, significant trauma, surgeries, any screening tests, previous studies and labs, known allergies, and medications (prescription, over-the-counter, supplements, and herbals). You can also include the patient’s family and social history here as well. Make note of any red flags as discussed above. Ask patients to describe all activities in which they are involved. For example, what kind of work do they do? Sports and exercise? Hobbies? If you suspect abuse, ask about family dynamics. If it hasn’t been done previously, a thorough review of systems must be conducted. PHYSICAL EXAMINATION POINTERS It is certainly reasonable to begin the physical exam with a focus on the musculoskeletal and neurologic exams. If possible, observe the patient as he sits, walks, and lies down in the waiting room, hallway, or exam room. Make note of habitus, posture, gait, level of comfort, and signs of distress. Observe his reactions to the various tests as well. Be sure to grade and compare all findings bilaterally (pulses, reflexes, muscle strength). Palpate the musculature of the neck and back, as well as the spinous processes, for tenderness. Compare your exam findings to the patient’s history. Again, be alert for red flags. If you suspect a more serious etiology, conduct the necessary exams and order the appropriate studies. For example, one could never be faulted for performing a cardiovascular exam for a patient with thoracic back pain or a bone density scan for an elderly patient who reports no acute injury. In the case study above, a testicular exam conducted five months after the onset of symptoms revealed palpable testicular masses. It is understandable that such an exam was not performed on the patient’s first visit. However, when the initial treatment failed, no other course of action was undertaken. The patient was examined the same way, asked the same questions, and treated the same way each time. This is a potential problem when a patient is managed solely in an urgent care facility or emergency department. There is an inherent lack of continuity of care in these facilities because, by their very nature, they are designed to manage acute or emergent conditions. In contrast, a primary care physician can follow a patient’s course and make modifications more easily. In this setting, the practitioner can systematically progress through the differential diagnosis list until the correct diagnosis is determined. When it is difficult to explain back pain in terms of musculoskeletal or neurologic causes, you must consider other body systems in the differential (see table below). Cardiovascular, gastrointestinal, and genitourinary conditions are all possible causes of back pain. Inspection, palpation, percussion, and auscultation remain the cornerstones of the physical exam and should be applied liberally in an attempt to gain as much information as possible regarding the patient’s physical status. As you gather information from the history and physical exam, you can narrow your focus, and from there determine what is the most likely underlying condition and what is the most serious possible underlying condition. Rule these in or out based on further work-up. Also, develop a plan of what you will do if these options fail. In the case study above, this last step was not performed and a nonmusculo-skeletal cause was not included in the differential until the family medicine physician was consulted.
TESTS TO ORDER When the patient presents with back pain without accompanying red flags, it is reasonable to treat conservatively without ordering imaging studies and lab work. Often, a complete history and physical exam are sufficient. Rarely is a fracture the cause of pain when there has been only minor trauma. Therefore, plain radiographs taken during the initial evaluation of such a patient provide very little, if any, useful information. The exception to this rule is the elderly patient at risk for osteoporosis. If you suspect a fracture, anteroposterior (AP) and lateral views will suffice. If the patient returns without improvement or worsening of symptoms, you must decide what tests to order. Again, this decision should be made based on the information provided during the history and physical exam. A “shotgun approach” is not cost-effective and no more valuable than a well-informed decision individualized to your patient. If you suspect a tumor as the cause of back pain, you must work up the patient to confirm the diagnosis and to determine the primary malignancy, if necessary. Lab studies may reveal an elevated ESR and increased alkaline phosphatase, as well as anemia and hypercalcemia. Hematuria may suggest renal cell carcinoma. Prostate-specific antigen levels must also be evaluated. Magnetic resonance imaging remains the gold standard for detecting spinal masses. Other valuable studies include chest x-ray, mammography, computed tomography (CT) of the chest, abdomen, and spine, and ultrasound of the abdomen and pelvis. A digital rectal exam and testicular exam must be performed. Cancers known to metastasize to the spine include breast, lung, thyroid, kidney, prostate, non-Hodgkin’s lymphoma, multiple myeloma, colorectal carcinoma, and sarcoma. When the history and physical exam findings suggest infection as a possible etiology, your subsequent work-up should include an ESR, a CBC, and possibly a C-reactive protein level. In the patient with systemic symptoms, blood cultures should also be drawn. Again, MRI is the study of choice for suspected infections localized to the spine such as osteomyelitis and epidural abscess. Vascular and visceral disorders are also known causes of back pain. Physical exam findings are specific to each structural abnormality and are beyond the scope of this article. However, the same focused, purposeful approach to the diagnostic work-up should be maintained. One specific disorder is worth mentioning here—abdominal aortic aneurysm (AAA). The pain caused by an AAA can be due to compression of adjacent structures or by actual dissection of the aorta, in which case the pain is intense and unrelenting. The key physical exam findings in these patients are a palpable, pulsatile abdominal mass, possibly with asymmetric or decreased pulses in the lower extremeties, or an abdominal bruit. A CT scan is diagnostic for both AAA and aortic dissection. You should suspect cord compression in any patient presenting with incontinence, hyperreflexia, clonus, and a positive Babinski’s test. Pain usually precedes neurologic symptoms. On the other hand, cauda equina compression usually presents with urinary retention and hyporeflexia. Other symptoms such as saddle anesthesia, leg weakness, low back pain, and sciatica are variable and can occur with either syndrome. An MRI is the study of choice for suspected compression syndromes. Myelography, though invasive, is an option for those patients unable to undergo an MRI. Finally, if you suspect a compression fracture, pathologic causes must be considered when the history rules out osteoporosis and trauma. Thyroid function tests, 24-hour urine for collagen breakdown products, and serum calcium, phosphate, and creatinine level may provide helpful information. Serum and urine protein electrophoresis will confirm myeloma as the cause of pathologic fractures of the spine. Initially, AP and lateral radiographs should be ordered. If you visualize a fracture or the results are equivocal, you can then order an MRI. This will better reveal spinal cord involvement as well. SYSTEMATIC APPROACH It is important to evaluate each patient in your care with a systematic, objective approach. This is especially true when evaluating the patient with the chief complaint of back pain. If you obtain a complete history and review of systems and conduct a thorough yet focused physical exam, you can better determine the best course of action. Finally, familiarizing yourself with the differential diagnosis and the red flags of more serious pathology will aid you in the challenging task of managing the patient complaining of back pain.
Suggested Reading
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