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10 marksDrNB 2025NeurologyCranial Neuropathy

a) List the causes of facial diplegia. [4] b) Discuss in detail the approach, diagnosis and management of facial diplegia. [6]

Facial diplegia refers to bilateral paralysis or paresis of the facial nerves, resulting in weakness of both sides of the face. It is a rare neurological manifestation often indicating systemic or multifocal pathology (Harrison's 21e, Ch. 265).

Facial diplegia occurs due to bilateral involvement of the facial nerve nuclei, fascicles, or peripheral nerves. Causes can be broadly categorized into inflammatory, infectious, neoplastic, traumatic, metabolic, and idiopathic.

Cause CategorySpecific Etiologies
InfectiousLyme disease, HIV, Tuberculosis, Herpes simplex/zoster, Leprosy
InflammatoryGuillain-Barré syndrome (Miller Fisher variant), Sarcoidosis
NeoplasticBrainstem glioma, Lymphoma, Parotid tumors (bilateral), leptomeningeal carcinomatosis
TraumaticBilateral temporal bone fractures, iatrogenic injury
MetabolicDiabetic cranial neuropathy, Amyloidosis
IdiopathicBilateral Bell’s palsy (rare)

Mnemonic for causes: “I I N T M I” (Infectious, Inflammatory, Neoplastic, Traumatic, Metabolic, Idiopathic) (Bradley's Neurology, 8e).

References

Bradley's Neurology, 8eHarrison's 21eHarrison's 21e, Ch. 265Harrison's 21e, Ch. 265; Bradley’s Neurology, 8e