Which nerve is most commonly involved in Sarcoidosis ?

Cranial neuropathies are the most common manifestation of neurosarcoidosis . Any cranial nerve (CN) may be affected, and multiple cranial nerve involvement is common. The most frequently affected CN is VII, and sometimes bilateral facial neuropathies are present . Optic neuropathy is also not uncommon . Involvement of CN VIII (uni- or bilaterally) can cause auditory or vestibular dysfunction , but it may be asymptomatic and detected by brainstem auditory-evoked responses . Nerves involved in eye movement (CN III, IV, and VI) may also be affected. Olfactory involvement is somewhat uncommon and causes anosmia and impaired taste Cranial neuropathies may occur because of basilar meningitis, but infiltration or compression of nerves along their course can cause their dysfunction. For example, olfactory nerve dysfunction can occur from olfactory bulb involvement as well as from involvement of the nasal mucosa . In the latter instance, it can be diagnosed by nasal biopsy. In addition, some facial neuropathies probably occur from basilar meningitis, while other cases may be due to granulomatous involvement of the extracranial poion of the nerve. Ref - pubmed.com