A comment is made here concerning a dramatic syndrome of acute ataxia that occurs in the context of an infectious illness, mainly in children. The syndrome was originally described by Westphal in 1872 following smallpox and typhoid fever in adults, but Batten is credited with drawing attention to the more common ataxic illness that occurs after common childhood infections such as measles, pertussis, and scarlet fever. Currently, acute ataxia of childhood is most often associated with chickenpox (about one-quarter of 73 consecutive cases reported by Connolly et al), but it can occur during or after any of the childhood exanthems, as well as in association with infections caused by enteroviruses (mainly Coxsackie virus), EBV, Mycoplasma, CMV, Q fever, vaccinia, a number of vaccinations, rarely following HSV, and also after nondescript respiratory infections (see Weiss and Guberman). The condition, as mentioned, is far less frequent in adults, but we encounter a case every few years in adolescents and individuals in their twenties; besides a case of varicella that we observed in a 25-year-old, the most common preceding organisms in these individuals have been EBV and Mycoplasma.
This illness, which is essentially a “meningocerebellitis,” appears relatively abruptly, over a day or so, and consists of limb and gait ataxia and often, but not uniformly, dysarthria and nystagmus. Additional signs include increased limb tone, Babinski signs, or confusion. The fever of the original infection may have abated, or it may persist through the early stages of the ataxic illness. As a rule, there is a mild pleocytosis; the CSF protein is elevated or may be normal. The MRI is normal in the majority of cases but some show enhancement with gadolinium of the cerebellar cortical ribbon. Most patients make a slow recovery, but permanent residua are known to follow. Because the benign nature of the illness has precluded extensive pathologic study, there is uncertainty regarding the infectious or postinfectious nature of these ataxic illnesses. Some cases have shown an inflammatory pathology most suggestive of a postinfectious process (see
Chap. 35), but the finding of fragments of VZV and Mycoplasma genomes in the spinal fluid by means of DNA amplification techniques favors a primary infectious encephalitis, at least in some instances.
Herpes zoster (“shingles,” “zona”) is a common viral infection of the nervous system occurring at an overall rate of 3 to 5 cases per 1,000 persons per year, with higher rates in the elderly. Shingles is distinctly rare in childhood. It is characterized clinically by radicular pain, a vesicular cutaneous eruption in dermatomal patterns, and, less often, by segmental sensory and delayed motor loss. The pathologic changes consist of an acute inflammatory reaction in isolated spinal or cranial sensory ganglia and lesser degrees of reaction in the posterior and anterior roots, the posterior gray matter of the spinal cord, and the adjacent leptomeninges.
The neurologic implications of the segmental distribution of the rash were recognized by Richard Bright as long ago as 1831. Inflammatory changes in the corresponding ganglia and related portions of the spinal nerves were first described by von Barensprung in 1862. The concept that varicella and zoster are caused by the same agent was introduced by von Bokay in 1909 and was subsequently established by Weller and his associates. The common agent is varicella or VZV, a DNA virus that is similar in structure to the virus of herpes simplex. These and other historical features of herpes zoster were reviewed by Denny-Brown et al and by Weller et al.