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Acute Low Back Pain: Guidelines for Treating Common-and Uncommon-Syndromes

Acute Low Back Pain: Guidelines for Treating Common-and Uncommon-Syndromes

ABSTRACT: Most patients with nonspecific
low back pain recover spontaneously within
4 to 6 weeks. Patients who resume their
normal activities as soon as possible generally
recover faster than those who stay in
bed; analgesics speed recovery. Sciatica is
usually caused by a herniated disk. However,
if the patient has a demonstrable neurologic
deficit, obtain plain radiographs to rule
out tumor, spondylolisthesis, fracture, and
infection. Administer high-dose intravenous
corticosteroids immediately to patients with
suspected epidural compression syndrome.
Back pain in a patient with a history of cancer
may indicate metastasis to the spine. If
a cancer patient has new or aggravated
symptoms, start corticosteroid therapy and
order plain radiographs and MRI scans.

Although acute low back pain usually
resolves within 6 weeks—with or without
treatment—the pain may signal a
significant neurologic or life-threatening
disease that warrants immediate
intervention.

In a previous article (CONSULTANT,September 1, 2002),
we reviewed the key aspects of the initial
examination, with an emphasis on
"red flags" that identify patients at risk
for serious disease. Here we focus on
the evaluation and treatment of back
pain syndromes, including acute lumbosacral
strain, low back pain with
sciatica, and epidural compression
syndromes (spinal cord compression,
cauda equina syndrome, and conus
medullaris syndrome). We also address
the diagnostic dilemma of back
pain in patients with a history of cancer.
In an upcoming article, we will review
the evaluation and treatment of low
back pain in children and adolescents.

NONSPECIFIC BACK PAIN
Most patients with acute low back
pain have conditions that may be classified
as acute lumbosacral strain. This
symptom complex has different
names, including back strain/sprain,
mechanical back pain, and lumbago
(acute low back pain without sciatica
or neurologic deficit). Strain and sprain
have never been histopathologically
documented in these patients, however.
Perhaps a more accurate term
would be "idiopathic" or "nonspecific"
low back pain, since a more precise diagnosis
will never be made in up to
85% of these patients.1

Symptoms and diagnosis. The
patient typically complains of mild to
moderate low back pain that is aggravated
with movement and relieved with
rest. There is usually no significant
identifiable cause of the pain, nor are
there noteworthy findings on the physical
examination. The evaluation of any
red flags noted in the history or on
physical examination typically reveals
no significant underlying condition.

Monitor such patients for 4 to 6
weeks to see if symptoms improve.
Some studies suggest that 90% of patients
with acute nonspecific low back
pain recover spontaneously during
this period.2 "Watchful waiting" thus
ensures that the patient will not lose
time and money by undergoing unnecessary
procedures. If any red flags
appear or if the patient fails to improve, further evaluation using plain
radiography, MRI, or laboratory testing
is indicated.1

Relapses of nonspecific low back
pain occur in approximately 40% of patients
within the first 6 months.3 A recurrence
unaccompanied by red flags
may not require immediate referral or
diagnostic evaluation.

Treatment. Management involves
activity and analgesia. Manipulation
and other physical modalities are
sometimes used, although their value
is questionable.

Activity. In recent years, the therapeutic
benefit of activity in treating
nonspecific low back pain has gained
increasing recognition. Until the mid
1980s, 7 days of strict bed rest was
commonly prescribed. In 1986, a
study showed that 2 days of bed rest
was as effective as 7.4 More recently,
it has been demonstrated that patients
who resumed their normal activities
to the extent tolerable recovered
faster than those who stayed in
bed for 2 days or who performed
back mobilizing exercises.5,6

Counsel patients with acute nonspecific
low back pain to continue their
routine activities insofar as possible,
using their pain as the limiting factor.
Discourage exercise until the acute pain
has resolved or improved significantly.

Analgesia. The mainstays of pharmacologic
therapy are NSAIDs and
acetaminophen. Although not all
NSAIDs have been evaluated for the
treatment of low back pain, it seems
likely that they are about equally effective.
7 However, one meta-analysis
showed that NSAIDs vary in their
side-effect profiles and toxicity.8
Ibuprofen was the least toxic of the 12
agents studied, particularly with regard
to upper GI tract bleeding complications.
Furthermore, there appears
to be a linear relationship between
dose and toxicity, so the lowest dose
possible should be used in patients at
risk. The concomitant use of misoprostol
or omeprazole reduces the risk
of clinically important GI tract bleeding
during NSAID therapy.8

Most clinicians consider
NSAIDs first-line therapy for acute
low back pain; no single drug has
been shown to be most efficacious.
However, there is no evidence that
NSAIDs are more effective than
acetaminophen for symptomatic relief
of low back pain or other musculoskeletal
syndromes.8 Thus, we recommend
using acetaminophen in
combination with NSAIDs or as the
sole initial agent when treating patients
at risk for adverse effects of
NSAIDs, such as the elderly and patients
with renal disease or peptic ulcers.
One regimen is acetaminophen,
650 to 975 mg q4 to 6h, either alone
or in conjunction with either ibuprofen,
800 mg tid, or naproxen, 250 to
500 mg bid (Table). A parenteral
NSAID, such as ketorolac, is no more
effective than oral ibuprofen in patients
with musculoskeletal pain.7

  Table — Drug therapy for acute lumbosacral strain: sample regimen
    Analgesics

Acetaminophen   Acetaminophen + NSAIDs Narcotic-analgesic combinations* Muscle relaxants

650 - 975 mg q4 - 6h   Acetaminophen, 650 - 975 mg q4 - 6h, + either ibuprofen, 800 mg tid, or naproxen, 250 - 500 mg bid Acetaminophen, Codeine phosphate, 30 mg, + acetaminophen, 300 mg, 1 or 2 tablets q4 - 6h; or oxycodone hydrochloride, 5 mg, + acetaminophen, 325 mg, 1 or 2 tablets q4 - 6h Diazepam, 5 - 10 mg q6 - 8h, or methocarbamol, 1000 - 1500 mg qid

*When prescribing narcotic-analgesic combinations that contain acetaminophen, warn the patient not to take another form of acetaminophen.

Narcotic analgesics may be prescribed
for patients with moderate to
severe pain. It is best not to prescribe
more than 1 to 2 weeks' worth of medication.
7 Combinations containing acetaminophen
and either codeine phosphate
or oxycodone hydrochloride are
listed in the Table. When prescribing
narcotic analgesics that include acetaminophen,
warn patients not to combine
them with other acetaminophen
products.

Other medications used to treat
acute low back pain include muscle
relaxants and corticosteroids. Muscle
relaxants, such as diazepam, 5 to 10
mg q6 to 8h, and methocarbamol, 1000
to 1500 mg qid, are as effective as
NSAIDs; however, there does not
seem to be any synergistic benefit
when these agents are used in combination.
7 Muscle relaxants are most
useful for treating back pain accompanied
by muscular spasms.7 Corticosteroids
injected locally or in the epidural
space are occasionally used, although
their benefit has not been
demonstrated.7

Manipulation. Manipulative therapy
is one of the more controversial
treatments of low back pain. Numerous older trials of short-term manipulative
therapy compared with other
treatments, such as medication, indicate
that manipulation may decrease
pain and improve function but that
it has little or no lasting benefit.2,4
However, more recent research has
shown that manipulation administered
acutely was no better than
physical therapy and only slightly better,
in terms of patient satisfaction
with care at 1 and 4 weeks, than an
inexpensive educational booklet.9 A
second study demonstrated that clinical
outcomes with manipulation
were no better than with standard
medical therapy.10 Because the utility
and cost-effectiveness of manipulation
have not been adequately demonstrated,
we do not routinely recommend
it.

Other physical modalities. These
include traction, diathermy, cutaneous
laser treatment, exercise, ultrasound
treatment, and transcutaneous electrical
nerve stimulation. None of these
modalities has been proved effective
for acute low back symptoms. Heat or
ice may provide temporary symptomatic
relief in some patients. Massage
has not been adequately studied, but
initial evidence is promising.1

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