Papilloedema in a Patient with Cervical Dystony - A Case Report

It is commonly known that the brain is separated from the osteocranium with three shells. There is subarachnoid cavity between the vascular and web shells. The brain is supplied with blood through the vessels of the internal carotid and vertebral arteries. Outflow of blood from the brain is carried out through the system of cerebral veins, venous sines and internal jugular veins. Healthy adult person has approximately 150 ml of blood in his vascular system of the brain and 100 ml of which in his venous system. The subarachnoid cavity is bound to ventricles of the brain and filled with the cerebrospinal fluid which is produced constantly, approximately, at the rate of 0.3 ml in min [4]. Because of the gradient between the intracranial pressure and pressure in the dural venous sinus, the absorption of cerebrospinal fluid is carried out in cover villuses and then its further transformation in the system of venules of the sagittal and sigmoid venous sines. The level of intracranial pressure is variable and depends on position of the body, respiration depth, increasing when coughing, when performing the Valsalva maneuver, when holding breath. 

It is known that one of the diagnostic sign of the increased intracranial pressure is edema of the optic nerve disc. The edema is caused by anatomic features of the subarachnoid cavity which stretches to the eye back pole [5,6].

At the same time, the patients with the cervical dystonia have tight and hypertrophied muscles of the neck which are so spastically strained that they arguably strangulate the veins blocking the blood outflow through them. As it was told above, outflow of the blood from the brain is carried out on the jugular veins. The jugular veins pass lateral sides of the neck. Perhaps, at that kind of cervical dystonia when the head is inclined sideways, that is at the laterocollis, the neck muscles spastically strained and strangulate the jugular veins, so as to block the blood outflow. In this regard, there is a local hypervolemia of the blood in dural venous sinuses of the brain. It is not excluded; the rising pressure leads to decrease of the blood pressure gradient between dural sinuses and cerebrospinal fluid in cover villuses of the subarachnoid cavity. Depression of the cerebrospinal fluid absorption in the villuses may be lead to increasing the intracranial pressure. Such intracranial hypertension is not as strongly evident as at total block of cerebrospinal fluid outflow pathways by a tumor or aneurysm. But nevertheless its long existence can lead to papilledema finally.

Shah VA, et al., [7] describe neurological picture of the intracranial hypertension after unilateral neck dissection. Kurschel, S et al., [8] report about a clinical case of existence of papilledema at the 13-year-old boy with torticollis, classifying it as secondary form of the idiopathic intracranial hypertension. Also, the clinical case-report of the papilledema with Arnold Chianti malformation type I was reported [9]. Popiela M, et al., [10] describe the bilateral papilledema at the patient with Camurati-Engelmann diseases, specifying about the edema reason following of the jugular veins strangulation.

Long term duration papilledema leads to block of axoplasmatic liquid current in nerve fibers. This can lead to neurodegeneration of nerve cells that was found by decreasing RNFL thickness in OCT investigation at the young man. This decreasing is not so strongly as optic nerve disc atrophy in expressed intracranial pressure.

In this study it is clear that the RNFL thickness decreasing comes not at once, and after several years from debut of laterocollis. This neurodegeneration is not strongly evident as it is about moderate rising of intracranial pressure owing to disturbance the venous outflow of the blood from the brain. In the studies Smith KA, et al., [11] it is established that at 82% of patients with the idiopathic intracranial hypertension had visual improvement and decreased RNFL thickness and indicators improved after stenting of dural venous sinus.

Obviously general nature of papilledema at laterocollis with the same changes at some astronauts at long duration space flight missions. These changes are described in literature as space-flight associated neuro-ocular syndrome [12]. One of the reasons of the syndrome also consists in the venous blood outflow disturbance on the jugular veins from the brain in the microgravity space flight [13,14]. Long observation over patients with similar pathogenesis of papilledema can bring more data for studying the influence of microgravity on the optic nerve.