RAMB Março/Abril 2016

nitial

approach

patients

with

acute

lower

back

pain

ssoc

ras

2016; 62(2):188-191

189

diseases that require specific intervention by specialists can

be identified in the initial assessment. The presence of red

flags increases the chances of underlying disease, which

can result in patient referral to a specialist. Causes that

should be ruled out primarily include spinal fractures,

cau-

da equina

syndrome, tumors and infections.

As for items that should be investigated during the

history-taking, the most important are: history of cancer,

especially in cases of bone involvement, recent rapid weight

loss, urinary incontinence or retention, prolonged use of

corticosteroids, osteoporosis, extremes of age (> 70 years),

fever, previous back surgery, major trauma, weakness or

loss of strength in the legs. Obviously, according to clin-

ical criteria, other issues may be raised and analyzed on

a case-by-case basis.

Henschke et al. evaluated 1,172 patients consecutive-

ly seen in basic units for acute low back pain.

Of the to-

tal, there were only 11 cases with serious underlying dis-

ease (0.9% of the total), of which 8 were spinal fractures.

Among the red flags associated with serious diseases,

chronic steroid use, age over 70 years and significant trau-

ma history were the most important. The authors em-

phasize that the presence of isolated red flags was com-

mon, which was not predictive of disease.

Physical examination

Commonly, local pain on palpation secondary to muscle

spasms are often documented. It gets worse when the pa-

tient bends down, performs extensions or bends.

Evaluation of neurological deficits is essential, with

assessment of the strength in the lower limbs. The pain

may radiate into the legs or thighs. Root compression re-

sults in severe pain in the legs, which may even be stron-

ger than the low back pain. L1 to L3 root compression,

although less common, occurs with pain in the hips and/

or thighs, while L4-L5-S1 compression occurs with pain

in the posterior thigh and leg, reaching all the way to the

foot, which is called sciatica pain. The Lasègue signal, also

known as straight leg raise referring to the elevation of

the stretched leg, results in worsening of nerve root com-

pression at L4-L5-S1, with worsening of the pain. Sciati-

ca pain is caused by disc herniation in most cases. The

evaluation of muscle strength is essential. Hip flexion

(L2), knee extension (L3), ankle dorsiflexion (L4), thumb

extension (L5) and plantar flexion of the foot (S1) are ex-

amined. The presence of neurological deficit, such as de-

creased muscle strength, requires neurosurgical evalua-

tion if there is any need for immediate surgical treatment.

Sensitivity should be appraised, especially if there is

a complaint of changes in the perineal area, as it can be

associated with

cauda equina

syndrome − massive hernia-

tion of intervertebral disc occurring with compression of

multiple roots sphincter dysfunction, which leads to uri-

nary and fecal retention commonly associated with bilat-

eral sciatica pain. When there is suspicion of sphincter

dysfunction, evaluation of sphincter sensitivity and tone

is critical.

adiological

assessment

For the vast majority of patients with acute low back

pain, the initial radiological evaluation is not required,

especially when there is no evidence of a serious under-

lying disease during history-taking and physical exam-

ination, given the benign and, generally, limited nature

of the problem.

7,8

In suspected cases of more aggressive

disease, although plain X-rays are widely available and

can diagnose fractures, radiographs have low diagnos-

tic sensitivity and specificity compared with magnetic

resonance imaging, which is the method of choice as it

allows excellent evaluation of bones, ligaments and neu-

ral components of the spine. If not available, comput-

ed tomography image reconstruction can be used. Phy-

sicians must be aware that adult and elderly patients

may have degenerative problems that must be correlat-

ed with the clinical picture in order to avoid misinter-

pretation of imaging findings.

aboratory

tests

Laboratory tests are of little use in most cases but may

play a role in suspected spinal infection (primary or post-

operative discitis) with complete blood count tests, blood

cultures and evidence of inflammatory activity. They may

also be useful in the differential diagnosis, as in the as-

sessment of urine to rule out nephrolithiasis, or amylase

in suspected pancreatitis.

ifferential

diagnoses

•

Nephrolithiasis/pyelonephritis: Pain radiating to

the genitals or perineum, in the anterior groin area.

Giordano signal present, signs of change in urinary

habits (frequency, smell, dysuria).

•

Abdominal aneurysm: Pulsatile mass in the abdo-

men, abdominal pain radiating into the lower back.

•

Pancreatitis/stomach and gallbladder disease: Ab-

dominal pain, food-related discomfort, vomiting,

pain radiating into the lower back.

•

Pelvic diseases: Perineal discomfort, discharge, pain

on palpation of the area.

•

Hip diseases: Pain on movement of the hip joint,

restriction of hip movement.