2.1. Case 1
This case describes a 21 months old, previously healthy boy, who presented with weakness of the lower extremities and lumbar pain after a mild upper respiratory tract infection. For this reason, he was immediately brought to the paediatric emergency department where he underwent a hip ultrasound that excluded a joint effusion. Nevertheless, he was dismissed with a diagnosis of transient hips arthritis and was treated with anti-inflammatory therapy. A few days later, because of worsening pain and the inability to walk, he returned to our department and was hospitalized.
On admission, a spine radiograph showed a slight reduction in the thickness of the L5 soma. Moreover, a spine magnetic resonance imaging (MRI) showed the T1 post-enhancement increased signals of the anulus L4–L5, of the opposite end-plates of L4 and L5, of the adjacent soft tissues and of the osteolytic area of the L5 pedicle. Therefore, a diagnosis of SD with associated osteomyelitis was made.
The blood exams revealed an increase in the inerythrocyte sedimentation rate (ESR) (77 mm/h,) and C reactive protein (CRP) (2.17 mg/dL, normal values < 0.4 mg/dL). In contrast, the patient had a normal white blood cell count (WBC) count, a normal procalcitonin serum concentration (0.12 ng/mL, normal values < 0.25 ng/mL), and a negative Quantiferon TB-gold test.
Broad-spectrum intravenous therapy with meropenem (100 mg/kg/day in three doses) and vancomycin (40 mg/kg/day in three doses) was started. Anti-inflammatory treatment was used for the first week and stopped with the complete resolution of the child’s symptoms and his return to normal walking.
After 3 weeks of therapy, the patient developed leukopenia with severe neutropenia (lowest WBC value of 5410/mm3
, with 80/mm3
neutrophils). As both of the administered drugs have been associated with neutropenia [5
], therapy was withdrawn and replaced with ceftazidime (100 mg/kg/day in three doses), which was carried on for another week until the second MRI. The images from this exam, performed after 4 weeks of total therapy, showed a reduction in the enhanced contrast, although there was not a complete resolution of the inflamed and infected state.
Because of the radiological improvement, the normalization of the inflammatory factors, and the absence of symptoms in the child, he was discharged with an oral therapy of linezolid (30 mg/kg/day in three doses) and cefuroxime axetil (30 mg/kg/day in two doses). After 12 weeks of oral therapy, another MRI was performed. The images showed a complete resolution of the infectious process. Figure 1
shows differences between the MRI at admission and during the follow-up. Therefore, therapy was stopped (the patient received 16 weeks of therapy in total). The child was completely asymptomatic, and all of the blood exams, including the acute phase reactants and blood culture, were in the normal range or negative.
All of the blood exams that were performed to determine the nature of the infection did not show positivity for any recent, causative infectious agent. Additionally, the immunological and autoimmunity screenings were normal.
The 3 year follow up did not reveal any problem after discharge. The child never felt additional pain or had problems walking again.
2.2. Case 2
A 3 years old boy was admitted to our emergency department because he had been suffering from intermittent lumbar pain for several months and had difficulty walking for a few days. The patient’s personal medical history was uneventful until 4 months earlier when, playing with a friend, the child had a lumbar trauma that caused neither detectable skin lesions nor impairment to leg mobilization, and was not investigated. However, in the following weeks, the child started to feel pain whenever his father picked him up and was clearly more irritable than he had been in the past. A fever was never reported. Three months after the trauma, because of the increased lumbar pain, the child refused to walk. For this reason, he visited an emergency care unit and underwent a physical examination; laboratory blood tests, including a WBC and CRP serum level; and a full spine radiography. No abnormal results were detected. Oral therapy with a nonsteroidal anti-inflammatory drug for a week was prescribed. During this period, a partial resolution of the pain was demonstrated.
However, ten days after the drug discontinuation, the pain worsened. Therefore, the child was brought to our department. Here, a physical examination, an abdominal ultrasonography, and the laboratory blood tests were still normal or only slightly abnormal. The ESR reached 60 mm/h, CRP was 1.47 mg/dL (normal values < 0.4 mg/dL), and procalcitonin was 0.26 ng/mL (normal values < 0.25 ng/mL), but the patient had a normal WBC count. His body temperature was in the normal range. However, an MRI scan of the spine revealed that a T1 post-enhancement had increased the signal of the anulus L3–L4 of the adjacent soft tissue; this outcome is highly suggestive of an infective SD (Figure 2
While awaiting the results of the blood culture, a broad-spectrum, anti-infective intravenous therapy was started with piperacillin–tazobactam (100 mg/kg/day divided into three doses) and vancomycin (40 mg/kg/day divided into three doses). Oral anti-inflammatory therapy was also provided.
The boy experienced rapid clinical improvement. In the first weeks, he stopped feeling pain and started walking again without lameness. Anti-inflammatory therapy was discontinued after several days. After 4 weeks of therapy, the boy underwent a second MRI, which showed no significant radiological change (Figure 2
). The CRP was negative, but the ESR and procalcitonin were still slightly abnormal. The therapy was modified, and piperacillin-tazobactam was replaced by meropenem (100 mg/kg/day divided into three doses), while continuing vancomycin.
After 8 weeks of intravenous therapy, the inflammatory index was completely negative, and the child felt no more pain and could walk normally. The intravenous therapy was switched to oral therapy with linezolid (30 mg/kg/day in three doses) and cefuroxime axetil (30 mg/kg/day in two doses), and the child was discharged from the hospital.
After 12 weeks of total therapy, another MRI was performed to determine if therapy should be discontinued. The MRI showed an important reduction in the signal alterations, although residual irregularities of the end-plates of L3 and L4 were reported (Figure 2
). On the basis of these findings, the child remained on antibiotic therapy for another month and then stopped. He received 16 weeks of therapy in total.
During hospitalization, all of the immunological exams that were performed were normal, and no causative infectious agent was documented. The whole therapy was well-tolerated, without any side effects.
During a 3 year follow-up, the child experienced only one episode of back pain, for which he promptly underwent an MRI that ruled out the possibility of a reactivation of the infection, but he showed a slightly adipose evolution of the L3 and L4 body. After that episode, which rapidly and spontaneously resolved, the child never felt lumbar pain again and maintained a normal life.