As a more chronic affliction, we have observed numerous cases in which cranial nerves were affected sequentially over a period of many years (polyneuritis cranialis multiplex). Two were later found to have tuberculosis of cervical lymph nodes (presumably tuberculous scrofula), and 3 had sarcoidosis. No cause was determined in the rest. Symonds had similar experience. It is usually worth obtaining a biopsy of an enlarged cervical lymph node in these circumstances.
The cavernous sinus syndrome, discussed in Chaps. 31, 33, and elsewhere in the book, consists of various combinations of oculomotor palsies and upper trigeminal sensory loss, usually accompanied by signs of increased pressure or inflammation of the venous sinus. The third, fourth, fifth, and sixth cranial nerves are affected first on one side only, but any of the processes that infiltrate or obstruct the sinus may spread to the other side. The main causes are septic or aseptic thrombosis of the venous sinus due to trauma, hypercoagulable states, or adjacent infections in adjacent structures, carotid artery aneurysm, carotid-cavernous fistulae, and neoplastic infiltration. Keane (1996) summarized his experience with an astonishing 151 instances of cavernous sinus syndrome and found trauma and surgical procedures to be the most common causes, followed by neoplasms (specifically those originating in the nasopharynx), pituitary tumors, metastases, and lymphomas; our experience has tended more toward local infectious causes in diabetic patients and hypercoagulable states.
A special cause of multiple cranial nerve palsies is an infiltration along the distal nerves in the skin and subcutaneous tissues by squamous cell carcinomas of the face, especially by spindle cell and other atypical varieties of tumor. A variant of malignant melanoma, “lentigo maligna” may do the same but has more of a tendency to infiltrate along larger nerves to the base of the skull and cause larger areas of loss of facial sensation and pain, vertigo, and deafness. This type of perineural spread first causes very restricted unilateral palsies and sensory loss related to the superficial branches of the fifth and seventh cranial nerves in one region of the face and then extends to the base of the skull and to the ventral brainstem. According to Clouston and colleagues, who have presented 5 cases in detail, the initial symptoms are usually pain and numbness in the area underlying the skin lesion and facial weakness confined to the same regions of the face; this pattern is a result of the proximity of fifth and seventh nerve branches in the skin and subcutaneous tissues. Various combinations of oculomotor palsies may follow as a result of tumor entry into the orbit via the infraorbital branch of the maxillary nerve. Occasionally there is no pain. We have also observed a similar regional pattern of extracranial involvement of trigeminal and facial nerves with an infiltrative mixed-cell tumor of the parotid gland.
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