In our case, clinical and laboratory tests were not indicative for Grisel syndrome: no significant blood tests, no inflammation, minimal increase in alkaline phosphatase and anti-streptolysinic title. Radiographic examinations revealed a first degree rotary dislocation.
In an attempt to reach a diagnosis, we also considered that AARS may be also present in Sandifer syndrome which is characterized by spasmodic posturing of the neck, back, or upper extremities associated with gastroesophageal reflux, esophagitis or a hiatal hernia.
We considered in differential diagnosis that AARS has been described in patients with autoimmune disorders, including juvenile idiopathic arthritis, ulcerative colitis, and HLA-B27-positive seronegative spondyloarthropathy ( 2, 3, 17). In our case we had no evidence of these pathologies. Not to be overlooked in differential diagnosis as well is Bow hunter's syndrome (BHS). It is rare cause of vertebrobasilar insufficiency that arises from mechanical compression of the vertebral artery by head rotation, severe vertigo, dizziness, right upper extremity tingling sensations and aggravated syncope when she turned her head. Our little patient had some BHS symptoms such as dizziness, vertigo, but she did not had blurred vision when turning the neck ( 8, 11, 12 ) .
Differential diagnosis with tumours should be considered, even if it is the least frequent cause of AARS. Brain tumours are the most common cancer in children < 15 years of age and are the 2nd leading cause of cancer-related childhood death. Diagnosis is generally based on radiological tests (usually MRI) and biopsy ( 15,19, 20 2, 22). Treatment may include surgical resection, chemotherapy and radiotherapy. Medulloblastoma is the most common malignant brain tumour in childhood. The peak incidence occurs in children aged between 2 and 7 years. The neoplasm is very rare in the adult population (over 21 years). This tumour is typical of the posterior cranial fossa, where it is located in both hemispheres of the cerebellum or in the cerebellar worm and being invasive and rapidly growing it usually spreads to other parts of the central nervous system (CNS) through the CSF: it can infiltrate the floor of the near fourth ventricle and extend into its cavity. It can also pass into the meninges. More rarely, it can give extra CNS metastases. Symptoms at the onset of neoplasia include loss of balance, lack of coordination, diplopia, dysarthria and, due to the involvement of the fourth ventricle (for which an obstructive hydrocephalus is common), signs of hydrocephalus, including headache, nausea, vomiting, unstable gait (10, 22). Treatment is based on a combination of surgery, radiation therapy and chemotherapy. Magnetic resonance imaging usually reveals a massive lesion with significant contrast enhancement involving the cerebellum. As mentioned above, medulloblastoma has a high propensity to locally infiltrate leptomeninges, as well as to propagate through the subarachnoid space to involve the ventricles, cerebral convexity, spinal leptomeningeal surfaces. Consequently, it is necessary to study with MRI the entire cranio-spinal axis. ( 7 ). Surgery is entrusted with the task of removing as much of the lesion as possible, in fact post-surgical tumour residues confer a worse prognosis. Pure harbinger of unfavorable prognosis is the presence of tumour cells in the cerebrospinal fluid or the detection of leptomeningeal metastases at MRI. Surgery alone is usually not curative. The addition of radiotherapy to the cranio-spinal axis, with focus on the primary tumour site, may result. Adding chemotherapy after radiation therapy increases the cure rate. With appropriate treatment, cases of long survival, over 3 years, for medulloblastoma patients, range from 60–80%. ( 10, 22 )
Diagnosis of atlantoaxial rotatory subluxation is difficult and often delayed. For a correct diagnosis of an AARD, clinical and radiographic evaluation are essential. The possibility of having Dual Energy TC available today allows you to have well-detailed images of the occipito-cervical tract, with limited exposure to ionizing radiation (7, 9, 14). MRI will however be irreplaceable for the differential diagnosis for non-traumatic situations (13, 15, 20, 21)
We reached the diagnosis that led us to the correct treatment after 4 days from the emergency access of the child. Perhaps the symptoms had been little understood even by the pediatrician for a long period. In our case, the symptomatology made it necessary to do the MRI and it was this examination that led to the diagnosis. In a case like this, delay or miss the diagnosis, could be catastrophic. MRI should be done promptly in every doubtful case.