Download Week 3:Low Back Pain

ACUTE LOW BACK PAIN
William R. Petricone, Jr., J.D., M.D.
WEEK 3: 01/17 – 01/21/05
Learning Objectives:
1. Recognize the key findings on history and physical examination that suggest
potentially serious causes of acute low back pain
2. Understand the appropriate diagnostic evaluation of acute low back pain
3. Know how to treat uncomplicated acute low back pain
CASE ONE:
J.B., a 45-year-old male building superintendent, presents to your clinic complaining of pain
in the lumbar region of his back bilaterally. Two days ago, while moving furniture, he felt
“something give way” in his lower back, and since then he has felt stiffness and pain to the
extent that walking is difficult.
Questions:
1. Why is it usually difficult to make a precise diagnosis in cases of acute low back pain?
Many spinal tissues (e.g. facet joint capsules, annulus fibrosus, ligamentum flavum, and
supraspinous, intraspinous and longitudinal ligaments) are innervated by nociceptive
fibers that can be stimulated by compression, stretching, or inflammation. Stimulation of
fibers in any of these tissues may trigger widespread contraction of paraspinal muscles,
resulting in diffuse and nonspecific low back pain. Furthermore, even when a patient has a
known anatomic defect, such as a narrowed disk space or a bony spur (osteophyte) on a
vertebral body, this may not constitute the source of the pain, because such defects are
common in asymptomatic patients.
2. What else would you want to know about the patient’s symptoms and general medical
history, and why?
Because a specific diagnosis usually cannot be made, and most patients improve with
conservative therapy, the history and physical examination are directed at identifying those
few patients who require more extensive or urgent evaluation. Specifically, the physician
should seek evidence of the following serious conditions:
a. Cancer: history of cancer, age over 50, pain that persists at rest, weight loss,
nocturnal pain, cigarette smoking
b. Infection: history of fever, intravenous drug use, endocarditis, rheumatic heart
disease, urinary tract infection or bladder instrumentation, immunosupressive
drugs, diabetes, exposure to tuberculosis
c. Inflammatory disease: age under 40, pain improved with activity or aggravated by
rest, insidious onset (more than three months), morning stiffness
d. Referred pain from regional disorders: history of peptic ulcer, kidney stones or
aortic aneurysm, “writhing” pain, sudden onset
e. Cauda equina syndrome: numbness or weakness in both legs, loss of bowel or
bladder function, “saddle” anesthesia, progression of neurologic symptoms over
hours or days.
In addition, a history of osteoporosis (or risk factors for it) would suggest the possibility of
a vertebral compression fracture.
3. Describe the key elements of your physical examination.
Back examination: Range of motion is rarely of diagnostic usefulness, but may indicate the
severity of the problem. Also, decreased range of motion in multiple regions of the spine
suggests a diffuse spinal disease such as ankylosing spondylitis. Point tenderness over a
vertebral body suggests osteomyelitis or compression fracture. An abrupt change in vertebral
alignment between spinous processes may indicate spondylolisthesis, but the sensitivity of
this finding is low.
Neurologic examination of the lower extremities: A positive straight leg raise test indicates
nerve root irritation. The test is not specific but 95 percent sensitive in patients with disk
herniation at L4-L5 or L5-S1. The crossed straight leg raise test is not as sensitive but
more specific for disk herniation. Examination of the motor and sensory distributions of the
sacral and lumbar nerve roots, especially at L5 and S1, is essential for detecting
neurologic deficits associated with back pain. Refer to Table 3.13-3 in the article for a
summary of the findings associated with each nerve root. Deficits of multiple sacral nerve
roots, caused by tumors or massive disk herniation produce the cauda equina syndrome:
loss of bowel or bladder function and anesthesia in the saddle area of the perineum and
buttocks. This is an emergency requiring immediate surgery, as it can progress to
permanent neurological impairment. Therefore, perineal sensation should be tested if the
syndrome is suspected.
General physical exam: Elements of the general physical exam may reveal evidence of
serious disease. For example, the following findings would be significant: fever, palpable
lymph nodes, absent pulses, heart murmur, and breast, pelvic, abdominal or rectal masses.
4. Assume the patient’s history and physical examination do not reveal evidence of
systemic disease or neurological deficit. What imaging studies, if any, would you
order? Would your answer change if the patient had evidence of disk herniation, such
as sciatica?
No imaging studies are indicated at this time. Plain x-rays are warranted only for patients
suspected of having infection, cancer, fractures or inflammation, or in selected patients
who fail to improve after two to four weeks of conservative therapy. In a patient over the
age of 50, an initial spine X-ray would be reasonable to evaluate for cancer. MRI should
be reserved for circumstances in which the information sought would change therapy.
Since most patients with disk herniation improve with conservative therapy, MRI should be
ordered only if the patient does not improve with conservative therapy and is a candidate
for surgery. Emergent MRI is required for any patient suspected of having an epidural
mass or cauda equina syndrome.
5. How would you treat this patient?
The key elements of conservative treatment of acute low back pain are analgesia and
education. Physicians have also traditionally recommended bed rest, but studies suggest
that, for most patients, continuing daily activities as tolerated is more effective. Short-term
physical therapy may be appropriate as part of the initial treatment or may be added later
if symptoms persist.
Nonsteroidal anti-inflammatory drugs are the analgesics of choice. Since all medications
in this class are about equally efficacious for most people, the least expensive ones,
ibuprofen and naproxen, may be preferred. Some patients, however, may respond better to
different agents, and use of longer-acting medications may improve adherence. The
selective COX-2 inhibitors carry a lower risk of gastrointestinal side effects than nonselective NSAIDs, but they may cost much more and are not more effective (current
controversy not withstanding). For example, ibuprofen 800 mg three times a day for thirty
days costs about $9, while celecoxib 200 mg twice a day for thirty days costs about $160.
(See table below.) Acetaminophen is an inexpensive alternative for patients who should not
use NSAIDs. For patients with severe acute back pain, opiates may be used for a short
time. Limited evidence supports the use of muscle relaxants, such as cyclobenzaprene.
These medications can cause drowsiness, but this can be an advantage at night.
All patients should be taught how to protect their back in daily activities. They should be
instructed not to lift heavy objects. They should be advised to use the legs when lifting, to
use a chair with arm rests, and to arise from bed by first rolling to one side and then using
the arms to push to an upright position. Overweight patients should be encouraged to lose
weight. Exercise programs that combine aerobic conditioning with strengthening of the
back and legs can decrease the frequency of recurrences.
BONUS QUESTION FROM MKSAP 13:
A 57-year-old man with a long history of intermittent back pain related to his work as
a truck driver presents with severe back pain radiating down his left leg that began
two days ago when he was helping a friend move. He says that his left leg feels weak.
He has to urinate one or two times per night and has slight urinary hesitancy.
Physical examination shows a heavyset man who has difficulty moving; his pulse rate
is 92/min and his blood pressure is 150/92 mm Hg; body mass index is 28. Left
straight-leg raise causes pain at 45 degrees, his great toe dorsiflexion is weak, and his
ankle jerk is diminished. Anal wink is present, the prostate gland is enlarged, and
sphincter tone is normal. No sensory level is detectable. He says that he has never
had pain like this before, and he asks for pain pills and to be able to go lie down.
Lumbosacral spine films are normal and erythrocyte sedimentation rate is 10 mm/h.
6. In addition to analgesics and clinical follow-up, what is the best management at this
time?
a) Lumbosacral traction therapy
b) Chiropractic adjustments
c) Physical therapy back school and exercise program
d) Referral to an orthopedic surgeon
e) Bedrest with activity as tolerated
Answer: E.
References:
1. Hellman DB. Low Back Pain. In: Stobo JD, et al. Principles and Practice of Medicine.
Stamford, Conn.: Appleton & Lange, 1996:261-265.
2. Epstein, PE, editor in chief. American College of Physicians. Medical Knowledge SelfAssessment Program 13. Primary Care Medicine. 2003. Item 106, page 164.
Additional References:
Textbooks:
1. Boyd RJ. Evaluation of back pain. In: Goroll AH, et al. Primary Care Medicine: Office
Evaluation and Management of the Adult Patient. 4th ed. Philadelphia: Lippincott Williams
& Wilkins, 2000.
2. Engstrom JW, Back and neck pain. In: Harrison’s Principles of Internal Medicine. 15th ed.
New York: McGraw-Hill, 2001:79-88.
3. Ruddy S, et al. Kelley’s Textbook of Rheumatology, 6th ed. Philadelphia: W.B. Saunders,
2001:509-523.
Journal Articles:
1. Atlas SJ, Deyo RA. Evaluating and managing acute low back pain in the primary care
setting. J Gen Intern Med 2001;16:120-131.
2. Deyo RA, Weinstein JN. Low back pain. New Engl J Med 2001;344(5):363-370.
3. Deyo RA, et al. What can the history and physical exam tell us about low back pain? JAMA
1992;268:760-765.
Other:
1. Bigos, SJ et al. Acute Low Back Problems in Adults. Clinical Practice Guideline No. 14.
Rockville, Md: U.S. Department of Health and Human Services; 1994. ACHPR Publication
No. 95-0642.
Cost of Commonly Used NSAIDs*
Medication
Aspirin
Ibuprofen (OTC)
Naproxen sodium (OTC)
Aspirin, enteric-coated
Naproxen sodium (prescription)
Naproxen
Indomethacin
Diclofenac sodium
Ketoprofen
Oxaprozin
Nabumetone
Celecoxib (as Celebrex)
Meloxicam (as Mobic)
Valdecoxib (as Bextra®)
Diclofenac + Misoprostol
Arthrotec)
(as
Dose Range (mg)
325  650 q4
200  800 tid
220  440 bid
325  650 q4
275  550 bid
250  500 bid
25 bid  50 tid
50  75 bid
25 tid  75 qid
600 1200 qd
1000 qd 1000 bid
200 qd  200 bid
7.5  15 qd
10  20 qd
50/200  75/200 bid
Cost Range
$3  $5
2 9
5  10
6  10
11  12
11  18
16  16
26  26
?  30
38  76
40  80
80  160
83  109
84  84
104  110
* Cost to the patient of thirty days’ treatment, rounded to the nearest dollar.
Source: drugstore.com, as of November 15, 2004.