The differential diagnosis of acute bifacial weakness
| Causes | Comments |
|---|---|
| Guillain–Barré syndrome | Presents with a variety of associated features. Acute inflammatory demyelinating polyradiculoneuropathy is the most common subtype to show cranial nerve involvement and pharyngeal–cervical–brachial weakness and Miller Fisher syndrome often have facial weakness. |
| Brainstem lesions and malignancy | Lesions at the level of the pontine tegmentum can affect both facial motor nuclei. These may be meningeal or parenchyma based. |
| Lyme disease | Acute infection may present as Bannwarth syndrome with meningitis, radiculoneuritis and cranial nerve palsies. The facial nerve is most frequently affected, and half of the cases have bilateral facial nerve palsy. |
| Syphilis | Syphilis displays protean disease manifestations and has the potential to produce cranial neuropathy, including facial nerve palsy, during the tertiary stage of disease with syphilitic meningitis. |
| Tuberculosis | Tuberculous meningitis may produce cranial nerve palsies. |
| Sarcoidosis | Cranial nerve neuropathy, particularly of the facial nerve, is the most common complication of neurosarcoidosis. Bifacial palsy may develop simultaneously or in sequence. |
| Sjögren's syndrome | Rare but documented association in the literature |
| Bell's palsy | Bilateral Bell's palsy is the most common cause of facial diplegia. It commonly presents with pain around the ear, hyperacusis, loss of taste and lacrimation. However, it should remain as a diagnosis of exclusion. |
| ‘Facial-onset sensorimotor neuropathy’ | A novel neurological entity, initially presents with facial sensory deficits, with a slow evolution in a rostral–caudal direction to affect sequentially the neck, upper trunk and limbs. |
| Neuromuscular disorders | Botulism or myasthenia gravis commonly present with bifacial weakness. |
| Acute myopathies | Polymyositis rarely causes bifacial weakness. |