A complete clinical history and a detailed clinical, otoscopic examination, audiogram tests, and complete blood count are mandatory in all children presenting with PFNP. In the absence of additional symptoms or specific findings on physical examination, the utility of further investigation is debatable. Manning et al. studied the causes of PFNP in 61 children and concluded that 50% of cases had Bell’s palsy, 14.8% had infections, 11.5% had injuries, and 3.3% had congenital problems. Grundfos et al. concluded that 84% of children had PFNP due to a specific etiology, and only 16% had Bell’s palsy as a diagnosis of exclusion. Particular causes of facial nerve palsy included injuries (24%), otitis media (16%), infections (12%), neoplasias (12%), and congenital anomalies (8%). In our study, no cause could be detected in 47.3% of the patients, infection was seen in 11(19.2%), trauma in 6(10.5%), and others in 13(22.8%) were due to congenital, immune, neoplastic, Melkersson Rosenthal syndrome, drugs toxicity and iatrogenic causes which were similar with Manning et al. results(21, 22).
A ten-year-old girl presented to our emergency department with facial immobility and inability to close her eyes or move part of her mouth. Her symptoms started one day previously with severe pain in the shoulder and extremities. Physical examination revealed PFNP and mild bilateral weakness of the extremities, hypoesthesia, remarkable deep-sensation deficit in lower and upper extremities, and loss of Achilles reflex. Diagnosis of Guillain-Barre syndrome was established based on physical examination and electroneurophysiological findings. After the treatment, PFNP recovered with three months. There are also some reports in the literature regarding patients with GBS presenting only with PFNP without any other symptom. So detailed examination is critical in every case of FNP (23)
Unilateral facial nerve palsy can be a rare presenting symptom of leukemia or leukemic relapse. In our study 1, patients diagnosed with AML after developing PFNP. In his examination, paleness and proptosis and abnormal CBC findings were red flags. Typical MRI findings cannot exclude the diagnosis of leukemia or leukemic relapse. Developing a focal neurological deficit in a patient with known leukemia warrants rigorous investigation and close surveillance for possible central nervous system relapse. In neoplastic facial palsy, the prognosis depends on the type and stage of neoplasm, and the therapeutic protocol applied in each case. PFNP in our patient recovered within four months, and the patient had bone marrow transplantation. (8, 24, 25).
Inappropriate treatment of acute otitis media can cause facial nerve palsy, mastoiditis, labyrinthitis. Ramsay-Hunt syndrome is caused by the varicella-zoster virus (VZV) reactivation, which lies in the sensory ganglion after primary infection. The syndrome is characterized by facial nerve palsy associated with a painful vesicular eruption within the external auditory canal and vestibulocochlear dysfunction (sensorineural hearing loss, vertigo, nystagmus, ataxia). EBV, CMV, mycoplasma pneumonia, also among the infectious causes(6, 11, 14). In our study, CMV, EBV, varicella-zoster, mycoplasma pneumonia, otitis media, otitis externa, and abscess led to PFNP in 11(19.2% ) patients. Patients with PFNP caused by infections recovered within 0.5–3 months. Some cases such as Ramsey Hunt syndrome may have worse prognosis. All these patients received combination treatment of corticosteroid and acyclovir in herpes or VZV infection, corticosteroid and ceftriaxone in complicated otitis media, and gancyclovir in CMV. PFNP, due to infectious causes, recovered within three months with the support of 2 weeks of corticosteroid and physical rehabilitation till recovery. The ongoing COVID-19 pandemic has affected millions of people worldwide and revealed several neurological syndromes related to this infection. But no cases of PFNP due to SARS-CoV-2 could be detected in our center.
Generally, the prognosis of facial nerve palsy depends on the cause. When caused by perinatal injury, Congenital facial nerve palsy has an excellent prognosis without treatment, while it is permanent when caused by congenital dysplastic structural reasons. In this case, the paralysis can be partly improved with plastic surgery procedures. Patients with traumatic facial nerve palsy recover within 30 months, with better results when the paralysis is partial or treated with steroids, physiotherapy, or surgical procedures(4). In our study, the patient who had PFNP due to trauma recovered within seven months due to a mild injury, immediate surgical intervention and extensive support of physical rehabilitation therapy were given. But PFNP in the patient with birth trauma didn't show any improvement. This situation could be due to the severe degree of the birth trauma.
One of the rare reasons for FNP in children is hypertension. The ignorance of this etiological reason could lead to delayed diagnosis or even worsening hypertension due to the administration of steroids for the idiopathic nerve palsy. Many authors recommend the measure of blood pressure in all patients with facial paralysis. It is essential to mention that we found several datasets that support PFNP as the first symptom of hypertension in children.(26) In our study, no hypertension were detected in any patients. But measuring blood pressure is essential in every issue of PFNP.
PFNP, especially the recurrent palsies, are uncommon disorders. In literature, it was observed patients with recurrent PFNP, diagnosed with celiac disease (CD) several months later. Because this observation and other neurological symptoms may be the only manifestation of atypical forms of CD. In our study, a five-year-old girl suffered from CD for 12 months before developing PFNP for the first time; no other attacks were detected during follow-up (2, 4, 25). Recurrent PFNP was seen in two cases, the first one diagnosed as Milkersson Rosenthal syndrome and the other one was considered idiopathic due to normal physical examination and laboratory and radiological test results except for B12 deficiency. Therefore this study cannot make causal inferences on the relation between B12 deficiency and PFNP. Nevertheless, there are many reported cases of neurological deficits due to B12 deficiency. One of these cases is a recurrent facial palsy in a 40-year-old woman who revealed primary Gougerot-Sjögren's syndrome. The onset of facial palsy has been linked with Gougerot-Sjögren's syndrome. The contribution of vitamin B12 deficiency is debatable in that case. So measuring B12 in cases of PFNP could be important, and thus supplying that patient with B12 could play a significant role in the treatment and prognosis (26, 27).
Iatrogenic FNP cases are also reported. Complications can occurred during mastoid surgery causing injury to the facial nerve. Early facial nerve exploration and neurolysis resulted in good facial nerve recovery. Some cases of PFNP secondary to superficial parotidectomy are also available in the literature (1, 2, 28). In addition, bilateral facial nerve palsy secondary to the administration of high-dose paclitaxel was also reported in a woman with breast cancer(13). In our study, there is one case of PFNP due to iatrogenic reason (during cochlear implantation surgery). At the same time, our study revealed a case of PFNP after tacrolimus treatment in a patient with renal transplantation.
MRI is beneficial in identifying brainstem pathology. High-resolution computed tomography scanning is better in evaluating the infratemporal portion of the nerve, especially in traumatic cases. Contrast-enhanced magnetic resonance imaging can identify sections of affected nerve in idiopathic facial palsy, but this test is not indicated in most children. More recent techniques such as constructive interference in steady-state and 3D-magnetization prepared rapid gradient echo can also be used to evaluate anatomical details of the inner ear and facial nerve. It should be indicated especially in patients presenting with atypical clinical findings and not improvinng as expected (6).
The treatment of idiopathic PFNP is controversial. The use of steroids early at the onset of palsy (within 72 hours) improves the prognosis and chances of complete recovery. This theory has been conducted depending on studies in adults. In children, the clinical benefit of steroids has not been proved yet. This is possible because most children with PFNP with or without use of steroids resulted in complete recovery. Many studies demonstrate that children generally have better outcomes. In patients unable to close their eyes, appropriate eye care is needed to help avoid corneal abrasions. This care can be provided by using artificial tears, sun protection, and rarely tarsorhaphy. Patients with Ramsay-Hunt syndrome should be aggressively treated with intravenous administration of acyclovir plus steroids. Patients with traumatic facial nerve palsy should be treated either with steroids and/or with surgical procedures. Depending on the severity of their condition, the treatment in Bell’s palsy is controversial due to the lack of extensive, randomized, controlled, prospective studies. Additional measures include eye protection, physiotherapy, acupuncture, botulinum toxin, or possibly surgery(28–30). In our study, methylprednisolone was started in 39 out of 57 patients which seem high, this could be due to a strong belief in strong effects of steriod that reported by many centers.
Assessing the prognosis of facial nerve paralysis can be difficult, especially in children, even if the possibility of a complete functional recovery is greater in pediatric cases than in adult ones. The grade is very important when determining the prognosis. Patients with partial paralysis have a better prognosis. The Ⅱ - degree, according to the House Brackmann scale, has a good outcome, while the Ⅲ and Ⅳ- degrees are associated with moderate residual dysfunctions. The Ⅴ and the Ⅵ degrees, instead, have the poor possibility of recovery. It has been reported that in about 5% of cases, the affected side may develop residual sequelae like contractures, spasms, synkinesis. The latter, in particular, affects symmetry and facial expressiveness. The most common synkinesis affects the eye and mouth muscles: during a voluntary movement of the mouth, for example, a smile, there could be an involuntary eye closure and vice versa. A similar phenomenon can occur with the autonomic fibers: for example, when eating, the activation of salivation also causes lacrimation (a phenomenon known as “crocodile tears”). No patient revealed such residual sequelae despite unrecovered 4 cases and partial recovery in 2 patients in our studies. In our study, prognosis of PFNP is good with complete recovery in about 80.7% of the cases, 3.5% experienced some kind of improvement, and 7% remained with severe sequelae, which similar with Joseph et al. results that showed complete recovery in about 80% of the cases, 15% experienced some improvement 5% were with severe sequelae(31–33).
Limitation of the study
As this study did not have a control group without steroid treatment, a comparative assessment of steroid treatment was unavailable.
In conclusion, peripheral facial nerve palsy is a rare condition in children with different causes. It could be idiopathic, congenital, or due to infectious, traumatic, neoplastic, and immune reasons. So, when a child presents with facial palsy, a complete clinical history and a detailed clinical examination are recommended. Giving attention to the red flag is very important. Peripheral facial nerve palsy in children is considered to have a good prognosis.