WHAT: Mononeuritis multiplex. Mononeuritis Multiplex: the simultaneous inflammation or degeneration of two or more peripheral nerves which are remote from one another. WHY: Mononeuritis multiplex can occur in polyarteritis if the nutrient arteries of peripheral nerve trunks are involved by the disease. HOW: The patient with mononeuritis multiplex may present with motor or sensory changes which occur in an irregular and asymmetrical distribution on his body. These changes may be areas of paresthesia or anesthesia, loss of deep tendon reflexes, weakness or paralysis of muscle group. For example, a typical patient might present with paresthesia of the radial aspect of his left hand representing involvement of the left median nerve and weakness of his right foot and ankle representing right tibial nerve involvement. REFS: 1) Lovshin, LL and Kernohan, JW: Peripheral neuritis in periarteritis nodosa: a clinicopathologic study. Proc Staff Meeting Mayo Clinic 24:48, 1949. DN19294-5. 2) Frohnert, PP and Sheps, SG: Long-term follow-up study of periarteritis nodosa. Am J Med 43:8, 1967. DN19295-3.