There may also be an association with migraines.In December 2020, the U.S. FDA recommended that recipients of the Pfizer and Moderna COVID-19 vaccines should be monitored for symptoms of Bells palsy after several cases were reported among clinical trial participants, though the data were not sufficient to determine a causal link. Genetics
A meta-analysis of genome-wide association study (GWAS) identified the first unequivocal association with Bells palsy. Pathophysiology
Bells palsy is the result of a malfunction of the facial nerve (cranial nerve VII), which controls the muscles of the face. Facial palsy is typified by inability to move the muscles of facial expression. The paralysis is of the infranuclear/lower motor neuron type. It is thought that as a result of inflammation of the facial nerve, pressure is produced on the nerve where it exits the skull within its bony canal (the stylomastoid foramen), blocking the transmission of neural signals or damaging the nerve. Patients with facial palsy for which an underlying cause can be found are not considered to have Bells palsy per se. Possible causes of facial paralysis include tumor, meningitis, stroke, diabetes mellitus, head trauma and inflammatory diseases of the cranial nerves (sarcoidosis, brucellosis, etc.). In these conditions, the neurologic findings are rarely restricted to the facial nerve. Babies can be born with facial palsy. In a few cases, bilateral facial palsy has been associated with acute HIV infection. In some research, the herpes simplex virus type 1 (HSV-1) has been identified in a majority of cases diagnosed as Bells palsy through endoneurial fluid sampling.
Blood cultures and cerebrospinal fluid cultures demonstrate Staphylococcus epidermidis, a coagulase-negative species of Staphylococcus. Biopsy of the kidney frequently demonstrates membranoproliferative glomerulonephritis, with deposits of C3, IgM, and IgG. Treatment
Management is focused on removing the infectious source. The shunt is removed immediately and antibiotics are begun. The infected shunt, typically a ventriculoatrial shunt, may be replaced with a ventriculoperitoneal shunt. Prognosis
In one review, over half of individuals with shunt nephritis made a complete recovery. An additional 40% of individuals had persistent urine abnormalities or end-stage renal disease. Death occurred in 9%. Epidemiology
Shunt nephritis is a rare condition affecting males and females of all ages. It occurs in approximately 0.7-2.3% of patients with shunt infections. Approximately 12% of ventriculoatrial shunts become infected, with Staphylococcus epidermidis being the infectious agent in 75% of cases. History
Shunt nephritis was first described by Black in 1965. Early cases and most cases since then are associated with infections of shunts that connect the ventricular system of the brain to the atria of the heart (ventriculoatrial shunts). Less commonly, shunt nephritis has been reported to arise from infections of shunts connecting the ventricular system to the abdominal cavity (ventriculoperitoneal shunts). == References ==