Toddler reluctant to sit

Clinical History

An 11-month-old Caucasian girl was admitted to hospital due to one-week history of reluctance to sit, irritability and inconsolable night crying. Two weeks before she had suffered from chickenpox and hand, foot and mouth disease which cleared up spontaneously. No other relevant medical history was reported; family history was unremarkable.

Imaging Findings

The paediatrician requested a pelvis X-ray (Fig. 1), abdominal ultrasound and hip ultrasonography (Fig. 2) since physical examination suggested a left hip-type pain. All these examinations were normal, excluding articular effusion or other pathologies. Since the baby girl still had pain and refused to sit, a brain and spinal MRI scan was planned and revealed a significant structural change of the entire L3/L4 segment: intervertebral disc height was markedly reduced and prolapsed dorsally, adjacent vertebral bodies were dishomogeneously hyperintense on the T2-weighted images and lost endplate definition on T1 weighting, suggesting erosive phenomena (Fig. 3). The use of Gadolinium contrast demonstrated intense enhancement of the intersomatic disc and the affected lumbar vertebrae (Fig. 4). There was also a cuff-like thickening of paravertebral tissues at L3-L4 level and inflammatory tissues in the anterior epidural space with no significant radicular compression (Fig. 5). Spinal bone marrow had a regular appearance.

Discussion

The term discitis (D) refers to intervertebral disc inflammation, while the terms vertebral osteomyelitis and spondylitis mean vertebral inflammation. As these two phlogistic processes are usually combined, a broader expression spondylodiscitis (SD) is commonly used. While adults SD start as a vertebral body's infection, children SD are caused by infectious D, as a result of the rich intersomatic disc vascularisation typical of the first eight years of age, which gradually disappears through adolescence [1, 2].
D and SD in children are uncommon disorders that have been diagnosed with increased frequency [3], especially between 6 months and 3-4 years [4]. Kingella Kingae is their main pathogen but unfortunately only improved molecular investigations reveal this Gram-coccobacillus [5, 6, 7] that commonly colonizes the oropharynx but can cause invasive infections in infants and young children, especially if recently exposed to a mild viral illness.
Signs and symptoms are subtle: children between 1 to 4 years usually have difficulty or refuse to walk or stand, irritability and constipation, while at 4-12 years abdominal pain is often reported and during adolescence low back pain is the main complaint [4]. Fever is low or absent, laboratory tests are unremarkable, possibly revealing increase in the value of inflammatory tests and leukocyte count; blood cultures, as mentioned, are often sterile [8, 9, 10].
Spine radiographies do not show any pathology, especially in the early (or latent) phase, which takes place within two to six weeks after the onset of the symptoms. X-rays can show narrowing of the disc space, irregularity of the vertebral endplates and sclerosis of the vertebral bodies’ contours, due to local regenerations [11].
The non-specificity of symptoms and of laboratory and radiographic findings explains considerable diagnostic delays, which is up to three months in 50% of patients [11]. Additionally, SD can lead to relevant problems such as spinal deformities, spinal abscess that require surgical interventions, neurological complications [11, 13].
Spinal MRI is the most sensitive and specific technique for diagnosing and monitoring this insidious disorder and once SD is suspected its early use is recommended in order to avoid delay in treatment and to ensure good long-term outcomes [4].
CT can easier reveal endplates erosion or other bony abnormalities but it's inferior to MRI in defining neural damaging [12].
In our case after MRI diagnosed SD a conservative treatment with antibiotics and immobilization was promptly initiated with an optimal clinical and radiological evolution (Fig. 6).

Differential Diagnosis List

Final Diagnosis

L3–L4 spondylodiscitis

URL:	https://eurorad.org/case/14512
DOI:	10.1594/EURORAD/CASE.14512
ISSN:	1563-4086