MRI findings of VIIth cranial nerve involvement in sarcoidosis

Case report. Atlantoaxial synovial cyst causing isolated unilateral hypoglossal nerve paralysis

Cervical synovial cysts are rare entities that are, most of the time, asymptomatic. They can cause nerve root or spinal cord compression, especially when acute haemorrhage or a marked increase in size occurs. Isolated unilateral hypoglossal nerve paralysis caused by compression of its cisternal segment is also an extremely rare condition. We report the case of a 51-year-old woman who presented with dysarthria and tongue fasciculation. MRI revealed an atlantoaxial synovial cyst that extended cranially through the hypoglossal canal and compressed the fibres of the left XII nerve on its cisternal segment. To our knowledge, this is the first case report of XII nerve paralysis being caused by an atlantoaxial synovial cyst.

Neurosarcoïdose : état des connaissances

The origins of neurosarcoidosis, a multisystemic granulomatous disease, remain unknown. Nervous system localizations remain rare, but severe. Lymphocytic meningitis, psychiatric disorders, diabetes insipidus and cranial nerve palsy are the most frequent signs. Cerebral fluid test and cervical medullar and cerebral MRI with gadolinium have to be performed first. In some cases, histological evidence of granuloma have to be obtained with neuromuscular, meningeal or cerebral biopsies. Functional impairment and life-threatening conditions require early corticosteroid therapy. In worsening cases or in the event of no therapeutic response or poor tolerance to corticosteroids, other immunosuppressive agents should be associated. Maintenance therapy and most often life long maintenance therapy allow a continuous success while avoiding relapse.

Movement disorders in patients with peripheral facial palsy

Acute unilateral facial paralysis is usually a benign neurological condition that resolves in a few weeks. However, it can also be the source of a transient or long-lasting severe motor dysfunction, featuring disorders of automatic and voluntary movement. This review is organized according to the two most easily recognizable phases in the evolution of facial paralysis: (1). Just after presentation of facial palsy, patients may exhibit an increase in their spontaneous blinking rate as well as a sustained low-level contraction of the muscles of the nonparalyzed side, occasionally leading to blepharospasm-like muscle activity. This finding may be due to an increase in the excitability of facial motoneurons and brainstem interneurons mediating trigeminofacial reflexes. (2). If axonal damage has occurred, axonal regeneration beginning at approximately 3 months after the lesion leads inevitably to clinically evident or subclinical hyperactivity of the previously paralyzed hemifacial muscles. The full-blown postparalytic facial syndrome consists of synkinesis, myokymia, and unwanted hemifacial mass contractions accompanying normal facial movements. The syndrome has probably multiple pathophysiological mechanisms, including abnormal axonal branching after aberrant axonal regeneration and enhanced facial motoneuronal excitability. Although the syndrome is relieved with local injections of botulinum toxin, fear of such uncomfortable contractions may lead the patients to avoid certain facial movements, with the implications that this behavior might have on their emotional expressions.

Facial palsy in Heerfordt's syndrome: electrophysiological localization of the lesion

Heerfordt's syndrome is characterized by fever, uveitis, swelling of the parotid gland, and facial nerve palsy and represents a variety of neurosarcoidosis. Since the first description of the syndrome, discussion about the lesion site has been controversial and has included the assumption of direct nerve compression by parotid gland swelling or a lesion within the facial canal in light of observations of accompanying taste disturbance. We report on a 26-year-old man with typical Heerfordt's syndrome who developed bilateral facial nerve palsy. Electrical and magnetic stimulation of the whole facial motor path provided strong evidence for a pathological process that: (i) began in the cerebellopontine angle; (ii) spread distally into the facial canal; and (iii) could be characterized by proximal demyelination. The patient recovered completely within 6 weeks under immunosuppressive therapy with steroids.