Fever and Upper Back Tenderness
Radiology Cases in Pediatric Emergency Medicine
Volume 7, Case 1
Daniel C.H. Kidani, Medical Student
Loren G. Yamamoto, MD, MPH
Kapiolani Medical Center For Women And Children
University of Hawaii John A. Burns School of Medicine
The patient is an 8 year old male who presents to
the emergency department with a chief complaint of a
two day history of fever. His maximum temperature at
home was noted to be 39.8 degrees C, axillary. He
also has a slight cough but no coryza. A brief review of
systems is unremarkable.
Examination in the ED: VS T 38.7 degrees C, P
115, RR 20, BP 114/49, oxygen saturation in room air
97%. He is comfortable and is in no apparent distress.
He appears non-toxic. HEENT unremarkable without
signs of acute infection. Neck is supple without
adenopathy, but his right sternocleidomastoid muscle is
slightly tender. He has reproducible point tenderness
over the thoracic spine, but he demonstrates full range
of motion of the spine. Heart regular rhythm with no
murmurs or extra heart sounds. Lungs are clear to
auscultation. Abdomen soft, non-tender, no masses
palpable, normal bowel sounds. No guarding.
Non-distended. No hepatosplenomegaly. Normal male
genitalia. His extremities are normal with good
perfusion. His sensation and strength are good. DTRs
What diagnoses are possible. What laboratory
studies or radiographs might be helpful at this point?
A CBC, blood culture and ESR are obtained.
Because of the point tenderness over his thoracic
spine, thoracic spine radiographs were ordered to
investigate the possibility discitis. His WBC is 10.8 with
66% segs, 28% bands, Hgb 13, Hct 49, platelets
220,000, ESR 3.
View his thoracic spine radiographs.
What are the radiographic findings in discitis?
These studies revealed a narrowing of the T3-T4
interspace. This narrowing is best seen on the AP film.
It is not easily identified on the lateral film.
View a coned down view of this area in some repeat
These coned down views of the T3-T4 region show
the narrowing on the AP and lateral views.
Based on these radiographs, he is diagnosed with
suspected discitis. He is hospitalized and IV antibiotics
are started. His fever eventually subsides during his
stay in the hospital and he is discharged on the fourth
hospitalization day. His blood culture does not grow
any organisms. His PPD is negative. A repeat ESR
during hospitalization is 2.
This patient does not have a typical presentation for
discitis, but his clinical and radiographic findings
suggest this possibility.
Although discitis has many clinical presentations, its
typical presentation is usually a young child, most often
under the age of 5, who presents with no or low-grade
fever (1). The affected disk can be at the lumbar,
thoracic, or cervical regions; however, the affected disk
is most often found in the lumbar region of the spine
which induces limping or the inability to walk. There is
also point tenderness around the area of inflammation
and a marked hesitation to flex the spine, which is
characteristically held stiff. Although the patient in this
case shows point tenderness over the thoracic spine,
which led the radiographic investigation for the
possibility of discitis, he did not demonstrate this
characteristic splinting or hesitation in flexing the spine.
In a patient with suspected discitis, a CBC, blood
culture, ESR and radiographs may be helpful (1). All
these investigations were done. Lab findings revealed
a borderline or normal WBC at 10,800, which is
common in discitis; however, his ESR, which is typically
elevated in discitis, was found to be low, at 3. These
two tests are nonspecific for discitis and are commonly
used to track the course of the disease. His blood
cultures were found to be negative throughout the
course of his hospitalization. This doesn't help to rule
out discitis since 50%-70% of cultures, both blood and
disk space, are found to be negative (1). The patient's
radiographs are characteristic for discitis,
demonstrating narrowing of the affected disk space.
He shows disk narrowing at the T3-T4 disk, which
corresponds to the point tenderness demonstrated on
physical examination. There was no evidence of soft
tissue abnormalities or associated bone destruction,
which may help to rule out a secondary infection from a
paravertebral abscess or osteomyelitis. Therefore,
even though the case presentation is rather atypical of
discitis, the diagnosis of discitis is possible in this case
given the radiographic evidence and the clinical
findings of fever and point tenderness over the affected
disk. The administration of a PPD test was given to
rule out tuberculosis infection, which has a higher
propensity for the spine than other bones (2).
Intervertebral discitis, the association of back pain,
progressive loss of intervertebral disk height, and
erosion of adjacent vertebral end plates (3), is an
uncommon entity. It is estimated that there are 1 to 2
cases of childhood discitis in a hospital that evaluates
32,500 patients a year. Discitis has a biphasic age
distribution, with a higher incidence early in childhood
and a subtler peak during adolescence (1).
The pathogenesis of discitis is not clearly
understood. Its propensity to develop in the pediatric
population is believed to be due to anatomical changes
that occur with age. In early childhood, vascular
channels within the cartilaginous region of the
intervertebral disk space as well as intraosseous
arterial anastomoses allow for a hematogenous route of
infection. With age, the intervertebral disk gradually
devascularizes. After the age of 30, it is thought that
disk inflammation is secondary to direct invasion (i.e.
paravertebral abscess, vertebral osteomyelitis).
Although it widely held that discitis is caused by an
infection, typically a blood borne bacterial or viral
infection of low virulence (4), the infectious agent is not
always clear since most cultures are sterile and many
patients recover without antimicrobial therapy (1).
Culture of the intervertebral disk by needle biopsy are
positive more often than blood cultures. However, all
cultures, blood or disk space, are negative in most
patients (50%-70%). This has led some to believe that
discitis may be caused by a partial dislocation of the
epiphysis, secondary to a flexion injury (5). When
cultures are positive, the most common organism is
Discitis occurs most often in patients under the age
of 5 who have no or low-grade fever. Discitis is
uncommon in children 8 years or older (1). The
affected disk is usually in the lumbar region, which
causes a progressive limp or the inability to walk. The
affected disk shows evidence of decreased height 2-4
weeks into the illness with variable degrees of damage
to the vertebral end plates (1). However, some patients
present with severe back pain, high fever, and
bacteremia, which is commonly seen in osteomyelitis.
Other patients show much milder symptoms even
though bacteria is isolated from blood cultures; still
others, show few signs and symptoms and no evidence
of infection (3).
The clinical manifestations may vary with age.
Infants may refuse to eat and be fussy, toddlers may
refuse to walk, while adolescents typically complain of
back, abdominal, or pelvic pain. However, the spine is
characteristically held stiff or in a splinted position, with
a tendency to avoid flexing the lumbar spine. The area
of inflammation should be evident on physical
examination. The lumbar lordosis is commonly
reversed and may be associated with paravertebral
muscle spasms. The presence of fever is variable (3).
Differentiation between discitis and vertebral
osteomyelitis is difficult early in the disease course as
the two entities are considered by some to be different
stages of the same disease spectrum. However,
vertebral osteomyelitis typically occurs in older
children, with a peak incidence in adolescence, who
present with fever and complain of lumbar, thoracic, or
cervical back pain. The patient is more likely to be ill
appearing and have a higher, longer lasting fever at the
time of diagnosis compared to the patient with discitis.
Radiographic evidence, which also lags behind clinical
symptoms, shows rarefaction of the involved vertebral
body followed by deterioration of bone, typically from
the anterior region of the vertebral body. MRI is the
diagnostic study of choice for patients with suspected
vertebral osteomyelitis since it is 96% sensitive and
93% specific on evaluation for this disease (1).
Radiographic evidence for discitis lags behind
clinical signs and symptoms. Radiographs are usually
interpreted as normal shortly after the onset of clinical
symptoms; however, subtle changes that are evident
early in the disease process (i.e. end plate
demineralization or irregularity) are often detectable in
retrospect. Two to four weeks into the disease
process, progressive narrowing of the intervertebral
disk is evident. If the radiographs demonstrate the
characteristic changes associated with discitis, this
supports the diagnosis of discitis. MRI may be more
Radionuclide scans may be useful in the early
detection of vertebral infections, such as discitis and
osteomyelitis. One study demonstrated that bone
scans allowed for an earlier diagnosis of disc space
infection relative to non-scanned patients, with an
average time after admission of 3 days compared to 11
days for the non-scanned group (5). However, bone
scans cannot differentiate between different disease
states and must be interpreted alongside other clinical
and diagnostic studies. It has been suggested, in the
advent of MRI, that nuclear bone scans should only be
used in very young patients in whom localization of
symptoms to the spine cannot be done solely on
physical examination (1).
CT can facilitate the diagnosis of discitis by
confirming the presence of disc narrowing and vertebral
end plate destruction earlier in the course of the
disease (4). However, like nuclear bone scans and lab
studies, CT typically provides nonspecific information
(1). Thus, it is especially useful when clinical evidence
of infection associated with back pain and neurologic
symptoms are present. CT is also better at
demonstrating areas of inflammation than a
MRI is the imaging study of choice for discitis. It is
more sensitive, 96%, than either bone scans or CT in
the diagnosis of disc space infections. Characteristic
changes include irregularity and destruction of the
vertebral end plates and body, increased signal
intensity on T2 weighted images, bone destruction
within adjacent vertebrae which are evident as low
intensity signals on T1 weighted images and high
intensity signals on T2 weighted images, and soft
tissue changes on all images (6).
If the patient shows constitutional symptoms and is
suspected of having a bacterial cause of infection,
initial treatment with immobilization and appropriate
antibiotics is indicated. The most common bacterial
isolate in discitis is Staph aureus; however, cultures
should guide antibiotic therapy. A minimum of 4-6
weeks of antibiotic therapy should be initiated if a
patient has a positive culture, elevated WBC, or
persistently elevated ESR. In patients who show
minimal symptoms and who have normal labs, the use
of antibiotic therapy is less clear. Immobilization in
such cases may be sufficient treatment (3).
Recommendations for immobilization include the use of
strict immobilization with a spica cast or modified
immobilization with bed rest with early mobilization in a
halo vest (7). It is recommended that a brace be worn
for 3 months following mobilization (5).
Operative procedures are indicated in patients who
do not respond to initial therapy, when there are
negative blood or closed biopsy cultures, neurologic
deficit, paravertebral abscess, and progressive spinal
deformity (7). In children, aggressive surgical
treatment is rarely needed, except in the cases of
tuberculosis or other caseating diseases that are not
responding to antibiotics (8). Patients treated
surgically typically have a more rapid resolution of
symptoms which may be secondary to decompression
of the infected disk space (9). Gebhard and Brugman
have shown that percutaneous discectomy of the
infected disc is effective in relieving symptoms,
obtaining a bacterial diagnosis, and helped to eliminate
the infection (9).
Discitis usually carries a good prognosis. Mortality
is extremely low, approaching zero, and recurrence is
uncommon. However, residual back pain, limited spinal
mobility and neurologic deficit can occur (7). In a study
by Bernard et al., which followed up 35 children (an
average of 17 years after they had intervertebral
discitis), 43% had residual back pain, 91% had normal
flexion of the lower back, 86% had markedly restricted
lumbar extension, and 80% had a narrowing of the
vertebral canal. These results did not seem to be
influenced by the type of treatment the patients
received (10). It was also suggested that the incidence
of back pain increased with age.
1. Fernandez M, Carrol CL, Baker CJ. Discitis and
Vertebral Osteomyelitis in Children: An 18-Year
Review. Pediatrics 2000;105(6):1299-1304.
2. Maguire JH. Osteomyelitis. In: Braunwald E,
Fauci AS, Hauser SL, Isselbacher KJ, Kasper DL,
Longo DL, Martin JB, Wilson JD (eds). Harrison's
Principles of Internal Medicine, 14th Edition CD-ROM.
McGraw-Hill, New York, 1998, pp824-827.
3. Wood GW. Infections of the Spine. In:
Behrman RE, Kliegman RM, Jenson HB (eds). Nelson
Textbook of Pediatrics, 16th ed. W.B. Saunders Co.,
Philadelphia, 2000, pp3094-3119.
4. Garcia FF, Semba CP, Sartoris CC, Sartoris DJ.
Diagnostic Imaging of Childhood Spinal Infections.
Orthopaedic Review 1993;22(3):321-327.
5. Glazer PA, Hu SS. Pediatric Spinal Infections.
Orthopedic Clinics of North America
6. Ozuna RM, Delamarter RB. Pyogenic Vertebral
Osteomyelitis and Post Surgical Disc Space Infections.
Orthopedic Clinics of North America 1996;27(1):87-94.
7. Harris LF, Haws FP. Disc Space Infection.
Alabama Medicine 1994;63(7):12-14.
8. Wood II GW. Infections of the Spine. In:
Canale ST (ed). Campbell's Operative Orthopaedics,
9th ed., Mosby Inc., St. Louis, 1998, pp3094-3119.
9. Gebhard JS, Brugman JL. Percutaneous
Discectomy for the Treatment of Bacterial Discitis.
10. Jansen BR, Hart W, Schreuder O. Discitis in
Childhood, 12-35-year Follow-up of 35 Patients. Acta
Orthop Scand 1993;64(1):33-36.
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