Causes of Facial Paralysis
The intricate nature of the facial nerve, traversing a narrow bony canal and innervating numerous facial muscles, renders it susceptible to a wide array of insults. Consequently, the etiology of facial nerve paralysis is remarkably diverse, making a comprehensive catalog impractical within the confines of a single article. Traumatic causes, while often readily apparent, represent only a fraction of the spectrum. These include:
Iatrogenic injury
Surgical procedures, particularly parotid gland surgery, mastoidectomy, and brain tumor resection, carry a risk of inadvertent nerve damage. The proximity of the facial nerve to critical anatomical structures necessitates meticulous surgical technique.
Direct mechanical injury
Basilar skull fractures, facial lacerations, and penetrating wounds can directly sever or compress the nerve.
Beyond trauma, a multitude of non-traumatic conditions can precipitate facial nerve paralysis:
Infectious Etiologies
Viral infections, such as herpes zoster (Ramsay Hunt syndrome), Lyme disease, and even common cold viruses, can trigger inflammation and subsequent nerve dysfunction.
Inflammatory Conditions
Sarcoidosis and other granulomatous diseases can involve the facial nerve.
Tumors
Intrinsic tumors of the facial nerve (e.g., schwannomas) or extrinsic tumors compressing the nerve (e.g., parotid tumors, acoustic neuromas) can lead to progressive paralysis.
Neurological Disorders
Multiple sclerosis, Guillain-Barré syndrome, and other demyelinating diseases can affect the facial nerve.
Vascular Causes
although less common, vascular compromise of the nerve can occur.