Bell’s palsy is defined as peripheral facial
palsy for which no cause can be found. Bilateral facial palsy is defined as paralysis, which affects both sides of the face simultaneously within a span of 30 days.
The Bell’s palsy may be bilateral, alternating, recurrent or familial. Melkersson Rosenthal syndrome is characterized by alternating recurrent facial palsy, facial oedema and fissured tongue. It might rarely present with bilateral facial palsy.
A 21 year old male patient presented with swelling of right half of the face since 10 months. There was inability to close both the eyes since 8 months.
The patient also had disarticulation of speech since 20 days. There was no history of any facial pain or numbness. There was no history of trauma, headache or motor weakness in extremities. There was no history of ear discharge, ear pain, tinnitus or vertigo. There was no past history of facial weakness. There was no family history of the cough, fever, weight loss, tuberculosis, diabetes, and hypertension.
On examination there was bilateral severe facial weakness. There was diffuse, non pitting oedema of the face. The oedema was most noted on the lips and parotid region. There was absent forehead wrinkling bilaterally. The tone of facial musculature was reduced bilaterally. All other cranial nerves were normal.
MRI brain was grossly normal. MRI face was suggestive of infective or the inflammatory myositis of infratemporal muscles.
HRCT chest revealed no anomaly. Gadolinium scan was negative for uptake. Routine haematological and urine investigations were normal. Serum glucose was normal. Pure tone audiogram was within normal limits. USG abdomen was suggestive of calculi in both renal calyces. Mild splenomegaly was found.
Serum ACE levels were significantly raised: 109 (0 to 52) U/L. HIV ELISA was non reactive. Monospot test and VDRL test were negative. ANA and RF were negative.
Electroneuronography studies showed more than 25% response within first 10 days of the palsy.
Lip biopsy didnot reveal any granulomas.
The patient was started on high dose methyl prednisolone. Facial massage and exercises were advised along with eye care.
The patient had significant improvement within 2 weeks.
The differential diagnosis of bilateral palsy involves several factors. As the facial paralysis is bilateral, it can not easily be classified as peripheral or central facial nerve paralysis. As subsequent therapy depends upon the location and elucidation of the aetiological agents, diagnosis must be based upon inclusion or exclusion of several factors
The aetiology of facial palsy has several theories. It can be because of vasospastic phenomenon in the peripheral nerve, viral infection, allergy, caloric effect on the peripheral nerve.
- Congenital: Diagnosis becomes apparent shortly after the birth as partial or total lack of the facial expressions. The facial paralysis may be due to congenital facial nucleus agenesis (Mobius syndrome) or thalidomide toxicity. The facial palsy due to the birth trauma should be ruled out.
- Infections: It can be divided into central and peripheral origin.
- Central: This category includes malaria, meningitis, encephalitis, poliomyelitis, infectious mononucleosis, syphilis, tetanus, leprosy and diphtheria.
- Peripheral: It can be divided into viral and bacterial aetiologies. The commonest being, Herpes zoster osticus (Ramsay Hunt syndrome) which consists of aural herpetic vesicles and cranial nerve palsy usually VII nerve.
Bilateral involvement due to peripheral bacterial infection may result from chronic mastoiditis with or without cholesteatoma. The treatment is mainly antibiotics for the immediate onset paralysis. Delayed onset facial palsy is most probably due to erosion of the fallopian canal and requires immediate decompression.
- Neoplasm: Pontine gliomas and leukaemia can cause facial nerve diplegia. In the former, other cranial nerves are also involved with raised intracranial pressure. In leukaemia, the paralysis presents late.
- Trauma: Transverse fractures are more likely to cause facial paralysis than longitudinal fractures. Delayed onset facial paralysis is due to haematoma or oedema in the facial canal.
- Metabolic: Facial diplegia has been noted in diabetes mellitus and alcoholic neuropathy.
- Non inflammatory central lesions (pseudobulbar palsy): Involuntary facial motion inspite of voluntary bilateral paresis helps in distinguishing from bulbar palsy.
- Disease of non-neurogenic origin: These can mimic bilateral facial palsy. It includes congenital absence of the facial musculature and Myasthenia gravis.
- Association with diseases of uncertain aetiology.
- Landry Guillain Barre Syndrome: It presents as an infectious polyneuritis affecting primarily peripheral nerves, though there are bulbar, myelitic and cerebral forms. In terms of the cranial nerves, there is high affinity for facial nerve, as high as 27%. Isolated facial diplegia indicates poor prognosis. The aetiology is of unknown origin, a viral origin is suspected with the diagnosis dependent upon clinical findings and elevated spinal fluid protein level. It responds to steroid therapy.
- Heerfordt’s syndrome: It consists of bilateral parotid enlargement, iridocyclitis and cranial nerve involvement with sarcoidosis. Facial nerve may be involved unilateral or bilaterally. The facial nerve involvement is supposed to be because of the infiltration of the nerve by sarcoid granulomas. Steroids may help.
- Melkerson Rosenthal syndrome: This syndrome consists of furrowed tongue, angioneurotic oedema of the upper lip and facial nerve paralysis, may be familial. Facial nerve decompression is tried if steroid therapy fails.
- Bilateral bells palsy: After eliminating all causes of the facial nerve palsy there is still a significant number of cases who fall in idiopathic or Bellís palsy category. Bilateral facial palsy has been noted in 1.5% to 2% of total Bellís palsy patients.
A characteristic feature in cases of bilateral facial palsy, one side recovers almost immediately (3 weeks), while the other takes several months to recuperate. The most useful tool in measuring facial nerve function is electromyogram. However results are valid only 10-14 days after the onset of the facial palsy and of little use early in course of the disease. Accepted modes of the therapy are steroid administration, vasodilators and multivitamins. Facial nerve decompression has been performed in isolated bilateral facial palsy, but numbers of cases are not sufficient to warrant a general statement as to the advisability of the procedure.
The aetiologic diagnosis of bilateral facial palsy is based on history physical examination detailed evaluation and specific investigations. Classical recovery on one side precedes other side several months. The decision for the surgical intervention is not a judgement arrived at easily or universally accepted. It should be reserved for cases which donít respond to conservative therapy in a fair time period.
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