Activated T cells and Leu-7+ cells in Bell's palsy

Increased seroprevalence of Toxoplasma gondii in a population of patients with Bell's palsy: a sceptical interpretation of the results regarding the pathogenesis of facial nerve palsy

Facial nerve oedema and anatomical predisposition to compression within the fallopian tube seem to be the only generally accepted facts in the pathophysiology of Bell's palsy. Several infectious causes have been suggested as possible triggers of this oedema. Most of the suggested pathogens have been associated with facial nerve lesions during latent infections, reinfections or endogenous reactivations. The aim of this study was to investigate the seroprevalence of three such pathogens Toxoplasma gondii, Epstein-Barr virus (EBV) and cytomegalovirus (CMV) in a population of patients with facial nerve palsy. Fifty-six patients with Bell's palsy were included in the study. A group of 25 individuals with similar age and gender distribution was used as control. Seropositivity for T. gondii, EBV viral capsid antigen (VCA) and CMV-specific IgM and IgG antibodies was investigated 2-5 days after the onset of the palsy. Comparisons for both IgM and IgG antibodies against T. gondii attributed significantly higher seroprevalence in the patients' group than in the control group (p = 0.024 and 0.013, respectively). The respective examinations for EBV and CMV attributed no significant results. The roles of EBV and CMV in the pathogenesis of Bell's palsy were not confirmed by this study. However, a significantly higher seroprevalence of IgM- and IgG-specific T. gondii antibodies was detected in patients with Bell's palsy when compared to healthy controls. The possibility that facial nerve palsy might be a late complication of acquired toxoplasmosis may need to be addressed in further studies.

Delayed facial palsy following uneventful middle ear surgery: a herpes simplex virus type 1 reactivation?

In rare cases, a facial palsy appears a few days after uneventful middle ear surgery. The reason for this delayed palsy is unclear. One hypothesis is that it results from a reactivation of herpes simplex virus type 1 (HSV-1) in the geniculate ganglion of the facial nerve. From 1987 to 1996, in the course of over 1,800 middle ear operations, we observed 7 ipsilateral delayed facial palsies and investigated 5 of them using immunologic and virologic methods, including the polymerase chain reaction (PCR). We could detect HSV-1 genome with the nested primer PCR in the tongue swabs of 4 of the 5 examined patients with delayed facial palsy. The immunologic changes in these palsies are also compatible with a reactivation of HSV-1. We conclude that minimal stimulation of the facial nerve during middle ear surgery could result in a reactivation of HSV-1 in the geniculate ganglion, which may in turn lead to a facial palsy.