N. Motoi et al., NECROTIZING BACILLUS-CEREUS INFECTION OF THE MENINGES WITHOUT INFLAMMATORY REACTION IN A PATIENT WITH ACUTE MYELOGENOUS LEUKEMIA - A CASE-REPORT, Acta Neuropathologica, 93(3), 1997, pp. 301-305
A 64-year-old man in a severely immunocompromised state due to acute m
yelogenous leukemia died, respirator-unaided, about 10 h after the abr
upt onset of coma. An earlier blood culture had yielded Bacillus cereu
s. The autopsy, performed 2 h after death, demonstrated diffuse subara
chnoid hemorrhage without berry aneurysms, and the formalin-fixed brai
n was tinged with gray-brownish discoloration. The sections of the bra
in presented a whitish tint of the surface layer of all portion of the
cerebral cortices, even those in the sulci. Histological examination
of the brain revealed leptomeningeal B. cereus dissemination, and wide
spread necrosis of the leptomeninges and arachnoid vessels without inf
lammatory cell reaction. The grossly recognizable whitish surface laye
r of the cerebral cortex showed overt hyperchromatism, and contained n
eurons more degenerative than those located in the deeper cortical lay
er. The total absence of inflammatory reaction may be explained by a c
ombination of the immunocompromised state of the patient and the chara
cter of B. cereus infection, which in itself induces little inflammato
ry reaction. The prominent lesions were confined to the cerebral surfa
ce layer and leptomeningeal tissue including the arachnoid vessels, wh
ich were all bathed in the cerebrospinal fluid, suggesting that some n
ecrotizing toxins had been secreted into the fluid by the B. cereus. T
he necrosis of arachnoid vessels is thought to have in turn caused dif
fuse subarachnoid hemorrhage and marked disturbance of the cerebral bl
ood flow, resulting in the terminal coma.