Multilevel paediatric idiopathic intervertebral disc calcification : a case study

Paediatric idiopathic intervertebral disc calcification (PIIDC) is a rare, mostly self-limiting condition in children that was first described by Baron in 1924. The aetiology is unknown and to date fewer than 400 cases have been described. PIIDC is characterised by calcifications mainly affecting the nucleus pulposus of the intervertebral disc. Most often lesions are located within the lower cervical spine, followed by the thoracic spine. The most common reported symptoms include low grade fever, localised tenderness, torticollis and decreased range of motion of the spine in the affected region. We present a case of multiple level idiopathic intervertebral calcifications in a 12-year-old male. Level of evidence: Level 5


Background
Paediatric idiopathic intervertebral disc calcification (PIIDC) is rare with less than 400 cases reported since the first published case in 1924 by Baron et al. [1][2][3] The aetiology is unknown. 1 Several hypothesises have been described including minor trauma or a viral infection-induced vasculitis leading to a decreased nutrient supply of the disc. 2 Patients commonly present with torticollis with or without fever.
Cervical spine involvement is usually symptomatic whereas lumbar spine lesions are asymptomatic. 4,5IIDC is characterised by radiographic evidence of single or multiple level oval-shaped calcifications mainly affecting the nucleus pulposus of the intervertebral disc. 5,68]14 The prognosis is excellent, with 95% of cases reporting full symptomatic recovery within six months. 1,13,14Recurrence is rare. 1,15urgical decompression is indicated in cases with severe radiculopathy or acute worsening neurology. 1,11

Case presentation
A 12-year-old male presented to our emergency department with a five-day history of spontaneous onset neck stiffness and low grade fever.No recent trauma was reported, and his past medical history was unremarkable.On physical examination he did not show signs of photophobia, vomiting nor any focal neurological deficit.The patient had full range of motion of the neck; pain was only exacerbated with forward flexion.No torticollis was noted.Mild central vertebral tenderness at the thoracolumbar junction was present with some vague abdominal discomfort.
Laboratory findings revealed a raised C-reactive protein of 47 mg/L and ESR level of 64 mm/hr.Other results included a normal white cell count, serum calcium and alkaline phosphatase.A lumbar puncture was done and cerebral spinal fluid microscopy and chemistry was within normal limits.Our surgery department was consulted and investigations revealed no intra-abdominal pathology contributing to the pain.
The patient was admitted for bed rest, analgesia and non-steroidal anti-inflammatories.He responded within five days of admission with complete resolution of neck stiffness and pain.
At his six-week follow-up he had no signs of recurrence and complete symptomatic recovery, with radiographic imaging revealing minimal resolution of the calcifications.At the threemonth follow-up visit there were no signs of further radiographic resorption of the calcifications (Figures 5 and 6).Clinically the patient remained asymptomatic.

Discussion
Paediatric idiopathic intervertebral disc calcification is a rare entity.Tsutsumi et al. noted a male predominance with a male to female ratio of 8:5 and the majority of cases being in the 5-to 12-year age group. 413,16    Inflammation is hypothesised to be part of the pathogenesis due to the signs of low grade fever, leukocytosis, raised C-reactive protein, ESR and raised protein in the cerebrospinal fluid. 5,17ne theory is viral-induced vasculitis leading to disruption of the nutrient blood supply of the endplate and paediatric disc.This leads to temporary ischaemia followed by cellular necrosis and calcification. 18he combination of pain, fever and raised inflammatory markers may be suggestive of acute discitis.PIIDC differs from discitis in several ways.PIIDC resolves spontaneously without requiring antibiotic treatment.Discitis may have other radiological features including erosion of the adjacent endplates with disc collapse.This does not occur in PIIDC.Intervertebral disc calcification following an episode of discitis is very rare. 15ntervertebral calcifications can affect any region of the spine.Plain radiographs are sufficient to note the presence and extent of intervertebral disc calcification.Computer tomography can define the calcification more clearly and in the presence of neurological deterioration, spinal cord compression and suspected discitis magnetic resonance imaging is recommended. 6,14,17e cervical spine is most commonly affected followed by the thoracic and rarely the lumbar spine. 1,2,4PIIDC usually affects a single intervertebral level with multiple level disc calcification reported in less than 35% of cases. 1,6,10,13,14,19Multiple level disc calcification shows different rates of resorption for each individual lesion. 19IIDC differs from adult degenerative intervertebral calcification in that it mainly affects the lower cervical and thoracic spine compared to mid-thoracic and upper lumbar spine in adults.The nucleus pulposus is involved in children, and in adults the annulus fibrosis. 5,6In children the calcifications are transient with usually complete resorption. 12,14he most commonly reported symptoms include low grade fever, localised tenderness, torticollis and decreased range of motion of the spine in that affected region. 1,5,7,14Sensorimotor fallout has also been reported.Calcifications involving the cervical spine are much more likely to be symptomatic than lumbar disc calcifications. 4,5,20nterior or posterior disc herniation has been described in approximately 38% of cases. 1 Anterior herniation is often associated with dysphagia, and posterior herniation with radiculopathy and neurological deficits in cervical disc calcification.5,[7][8][9][10][11][12][13] PIIDC is a self-limiting benign entity, and conservative treatment is recommended for the majority of cases.15 Conservative measures include bed rest, analgesia, non-steroidal anti-inflammatory medication, physiotherapy and cervical orthotics.1,4,[6][7][8]14 The prognosis is excellent with complete symptom resolution noted in 66% of cases at three weeks and in 95% of cases at six weeks.13,14 Long-term complications include chronic back pain, scoliosis, loss of adjacent vertebral height and anterior osteophyte formation.

Conclusion
Multilevel paediatric idiopathic intervertebral disc calcification is a rare entity that requires radiological and biochemical investigations to exclude other more sinister spinal conditions.The identification of PIIDC and the understanding of its natural course is crucial.Management is largely symptomatic and multidisciplinary with predictable resolution of symptoms and resorption of the lesions over time.Only in exceptional cases is surgery considered.

Figure 5 .Figure 6 .
Figure 5. AP radiograph of the thoracic spine Figure 6.Lateral radiograph of the thoracic spine