Isolated and Recurrent Peripheral Facial Palsy Revealing Primary Sjogren’s Syndrome

Peripheral facial palsy (PFP) is often idiopathic; a secondary systemic cause is noted in less than 1.2% of cases. Primary Sjogren’s Syndrome (PSS) remains an exceptional and often insufficiently known etiology of facial paralysis, and only a few sporadic cases are reported in the medical literature. These inaugural forms of the disease represent a real diagnostic challenge for clinicians. We report an original observation of isolated and recurrent PFP as inaugural symptom of PSS in a 53-year-old female with no notable pathological history.


Introduction
Primary Sjögren's syndrome (PSS) is an autoimmune disease characterized by focal lymphoid infiltration of the exocrine glands, mainly manifested by dry ocular and oral syndrome [1]. During the course of the disease, one-third of the patients develop extraglandular lesions: pulmonary, neurological, renal, hepatic and cardiac, which signal the systemic nature of this disease and condition its prognosis [2,3]. The prevalence of this connective tissue disease is estimated at 1-3% of the general population [1,4] and can reach as much as 4.8% in Europe [2]. The neurological manifestations of this disease are observed in 15-20% of cases and are highly polymorphic and far dominated by peripheral neuropathy [5][6][7][8].
Neurological involvement may be the first manifestation of PSS in approximately 25% of cases [7]. Of all the possible neurological manifestations of PSS, peripheral facial palsy (PFP) remains exceptional and unusual [9], and only a few sporadic cases were reported in the medical literature [9][10][11][12]; these inaugural forms of the disease represent a real diagnostic challenge for clinicians.
We report an original observation of isolated and recurrent PFP as inaugural symptom of PSS.

Case Report
A 53-year-old Tunisian patient, with no notable pathological history, was referred to our department for recurrent PFP. She was treated by her family doctor for three episodes of PFP occurring within a year and a half without any other associated abnormalities.
This PFP was right in two times and left in one time. The etiological investigations requested by his treating physician, including a specialized ENT examination and a cerebral CT-scan, were without abnormalities. The diagnosis of idiopathic PFP (Bell's palsy) was retained. The patient was treated with short course corticosteroid and vitamin therapy but without improvement.
In somatic examination, the patient was apyretic, with correct conscious, respiratory, and hemodynamic status. We noted a marked dryness of the skin and the tongue.

Discussion
PFP is often idiopathic (Bell's palsy or FRP); a secondary systemic cause is noted in less than 1.2% of cases [13]. PSS remains an exceptional [11] and often insufficiently known etiology of facial paralysis [11,14]. Indeed, only a few sporadic cases have been reported in the literature [9][10][11][12]15]. In large series of PSS, this neurological manifestation remains unusual: in fact, only two cases of PFP associated with PSS were found in the series of Teixieira F et al of 93 patients followed for PSS [14], no case has was noted in the European series of 392 patients with PSS of whom 74 had neuro-Sjögren's [8], and no case of PFP was reported in the Ye W et al series of 566 patients with PSS of whom 184 had neurological signs [6]. PSS-associated PFP can be uni-or bi-lateral [12], episodic or most often recurrent [11], isolated or more often integrated in the framework of a complex neurological attack [11] and can remain for a long time the only manifestation of the disease [11,15]. PFP associated with PSS usually responds well to systemic corticosteroids and others specific therapies for this autoimmune disease.
These forms of isolated and SSP-revealing cranial neuropathies are often ignored and neglected by clinicians, and thus sometimes responsible for a very important diagnosis delay [16]. The exact pathophysiology of this neuropathy is not very well known. It appears to be multifactorial involving vasculitis, autoimmunity, inflammation, and cryoglobulinemia [4,5]. A reported case of PSSassociated PFP involved, in addition to these classic pathogenic factors, a vitamin B12 deficiency [11]. Finally, it should be kept in mind that a PFP for rapid onset and/or progression during PSS should raise concerns about the lymphomatous transformation of this disease [17].

Conclusion
Peripheral facial palsy is an exceptional and uncommon neurologic complication of PSS. The isolated and inaugural forms are often ignored by health practitioners and represent a real diagnostic challenge. It is thus necessary to evoke the diagnosis of PSS in front of any PFP that does not proven, particularly if recurrent and in elderly. Early diagnosis and adequate management can improve the prognosis of this disease, especially that a lymphomatous transformation can be announced by a PFP arising and/or progressing rapidly.