Radiculitis. Shingles (herpes zoster) is the prototype of a radiculitis. The radicular pain sometimes precedes the exanthematous delineation of the dermatome by days. The persistent, wearing, postherpetic pains are almost always accompanied by skin changes in the affected dermatome.


Borrelia radiculitis can begin and remain monoradicular. The pain, however, is often bilateral−zonal or saltatory−pluriradicular and ends without a skin rash in a radicular deficit syndrome. Rare etiologies are granulomatous processes like tuberculosis, sarcoidosis, and Behçet syndrome.

Clinical Findings. In contrast to most painful radicular affections, acute focal lesions of the plexus of peripheral nerves often proceed painlessly. This is mainly due to the high number of motor fibers and the different anatomical structures which make compression less likely compared to the anatomically restricted spinal ganglia. In addition, a circumscribed lesion of sensory fibers does not primarily cause pain, but instead, sensory loss or distortion (paresthesias, dysesthesias) in the sensory area. For example, compressive ulnar or radial pareses or a traumatic upper plexus paresis are generally painless. Even a neoplastic plexus compression may manifest as a painless leg or arm paresis with numb areas. Long lesions of mixed or sensory nerves, on the other hand, tend to cause neuralgiform pain, which must be delineated from radicular syndromes. Typical examples are the perioperative stretching of the sciatic nerve. Moreover, massive lesions of parts of a plexus or peripheral nerve with a large sensory volume (median or sciatic nerve) may cause deafferentation pain as observed after avulsion of a root.

Diagnostic Tests. Besides the diagnostically decisive neurological deficit syndrome, the abnormal Tinel sensitivity of the impaired sensory nerve is the most important diagnostic sign. With respect to the Tinel phenomenon, it must be kept in mind that even a healthy nerve can be stimulated mechanically (danger of false-positive signs if not tested on both sides) and that the positive Tinel sign and localization of the lesion must not necessarily correspond. For example, the Valleix pressure point, which represents abnormal Tinel sensitivity of the sciatic nerve at the buttock, is positive in the case of an S1 radicular compression as well as that of a sciatic lesion at the thigh.

Etiology. As is true with radicular syndromes, the signs and symptoms may not, or only to a limited extent, allow one to determine the etiology. The etiologic clarification entails two steps: first, localization of the lesion, then determination of its etiology.

In the arms and legs, entrapment and compression neuropathies as well as traumatic lesions are etiologically predominant, and all other causes are comparatively rare.