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We describe a 22-month-old boy with iron deficiency anemia and reactive thrombocytosis who developed vomiting, headache, mental status changes, and seizures. Computed tomography showed infarction of the basal ganglia and thalami. Magnetic resonance imaging revealed cerebral venous thrombosis, delineated the extent of the vascular and associated parenchymal involvement, showed the infarcts to be hemorrhagic (a finding not imaged by computed tomography due to our patient's depressed hemoglobin level), and obviated the need for invasive angiography.

To find out whether apparent seronegativity in patients strongly suspected of having Lyme disease can be due to sequestration of antibodies in immune complexes, such complexes were isolated and tested for antibody to Borrelia burgdorferi. In a blinded analysis the antibody was detected in all 10 seronegative Lyme disease patients with erythema chronicum migrans (ECM), in none of 19 patients with other diseases, and in 4 of 12 seronegative patients who probably had Lyme disease but had no ECM. These findings were confirmed by western blot, which also showed that immune complex dissociation liberated mainly antibody reactive to the 41 kD antigen and sometimes antibody to an approximate 30 kD antigen. Complexed B burgdorferi antibody was also found in 21 of 22 (95%) of seropositive patients with active disease, 3 additional seronegative but cell mediated immune reactive patients, and 3 other seronegative patients who eventually became seropositive. Apparent B burgdorferi seronegativity in serum immune complexes may thus be due to sequestration of antibody in immune complexes.

Infants and children with symptomatic human immunodeficiency virus (HIV) infection frequently develop neurologic disease with symptoms and signs of acquired microcephaly, developmental delays, encephalopathy, pyramidal tract signs, and less often, movement disorders and ataxia. However, clinical courses vary and, based upon progression of neurologic findings, we have classified them into 2 broad categories; progressive (loss of previously acquired language and cognitive skills) and plateau (failure to acquire additional developmental skills). We have used immunocytochemistry to localize HIV within the brains of neurologically involved children with AIDS. Interestingly, the brains of those children with a progressive neurologic course showed readily detectable HIV antigen, while those with a plateau course showed little or no detectable HIV. These findings suggest that in children with symptomatic HIV infection, the progressive neurologic deterioration is due to continued presence of HIV within deep white matter and gray matter, while the plateau neurologic course is due to HIV induced damage followed by either limited penetration of virus into the central nervous system, or clearance of virus below detectable limits.

We examined the spinal cords from 15 consecutive autopsies of infants and children with AIDS using a battery of histochemical and immunocytochemical stains, and in four cases, electron microscopy. Corticospinal tract (CST) signs were a notable clinical finding in 14; however, the age of onset, rate of progression, severity of dysfunction, and duration varied among patients. Ten cases had pathologic changes in the CST. In four of the ten cases, the changes were consistent with an "axonopathy" since axons and myelin were both diminished in the CST. These cases may represent CST wallerian degeneration, since they had marked injury to cerebral white matter in the form of chronic inflammation with multinucleated cells, gliosis, and myelin pallor. In five cases, with an average age at death of 31 months, the CST showed poor myelination with relative preservation of axons. These cases may represent delayed myelination or possibly cytokine-mediated injury to newly formed myelin since the CST is one of the last tracts to myelinate in the spinal cord. One child with primary CNS lymphoma had a complicated pattern of spinal injury due to unilateral CST wallerian degeneration possibly superimposed upon delayed myelination, in addition to patchy areas of demyelination associated with perivascular lymphomatous infiltrates. Four children with mild CST signs, ranging in age from 5 to 6 months, had CST myelin pallor that was consistent with the degree of myelination expected for age. We did not find vacuolar myelopathy similar to that seen in adult AIDS, but did note focal vacuolar changes in the thoracic posterior columns in the oldest child.

The neuropathologic findings of brains and spinal cords removed at autopsy from 26 infants and children with AIDS is described; in two cases, only the spinal cords were available. The most common finding in the brains was dystrophic calcification of blood vessels of all calibers in the basal ganglia and deep cerebral white matter (21 og 24 cases). The next most frequent finding was subacute encephalitis (SE) (15 of 24 cases) with microglial nodules and multinulceated giant cells. Immunocytochemical and in situ hybridization studies showed HIV antigen or genetic sequences only in the brains of cases with SE. Multinucleated giants cells (MGC) were the most frequent cells with reaction products. MGC were labeled with ricinus lectin (RCA), but not with leukocyte common antigen (LCA) or glial fibrillary acidic protein. Many cells in microglial nodules were labeled with RCA, but not LCA; cells in the perivascular compartment were labeled with LCA, but not RCA. Corticospinal tract degeneration was noted in 15 of 20 spinal cords. In six cases tract degeneration was consistent with delayed myelination, and the remaining cases had axonal injury consistent with Wallerian degeneration. Opportunistic infections were rare (three cases). Central nervous system lymphoma occurred in three children and was the most common mass lesion. In two cases lymphoma occurred in the setting of a systemic polyclonal immunoproliferation possibly related to Epstein-Barr virus infection. Cerebrovascular accidents were noted in seven cases. Two cases had hemorrhage associated with immune thrombocytopenia; one hemorrhage was catastrophic. Two children had large vessel arteriopathy with multiple encephalomalacias. Two children had a necrotizing encephalopathy with encephalomalacia and vascular changes suggestive of a mitochondrial cytopathy.(ABSTRACT TRUNCATED AT 250 WORDS)