Spinal meningitides with radiculo-myelopathy: Part 2. Pathology and pathogenesis

Abstract

1. (1) Pathological details and comments upon pathogenesis are presented in respect of 50 cases of spinal leptomeningitis, which fell into the following four groups: (i) 25 cases of primary subacute leptomeningitis mostly of tuberculous origin; (ii) 14 cases of spinal leptomeningitis secondary to intracranial tuberculous meningitis; (iii) 8 chronic cases of spinal "arachnoiditis" due to known irritative mechanisms; (iv) 3 cases of tuberculous leptomeningitis secondary to spinal caries. 2. (2) The variations of the pathological reaction in the spinal leptomeninges are detailed, and gradations from the overtly caseous, to the granulomatous, to the chronic inflammatory and finally, to the fibrosing variety are presented. Both local and extensive tubercular leptomeningitis occurred. The reasons why acid-fast bacilli were seldom isolated are discussed. 3. (3) Four main mechanisms leading to cord involvement are described: (a) oedema of border zones of the cord probably secondary to venous impediment due to pressure from the meningitis; (b) ischaemic myelomalacia resulting from vasculitis or post-thrombotic occlusion of meningeal vessels; (c) infrequent total infarction of cord resulting from such vascular involvement; and (d) the formation of intra-medullary tuberculoma with pericentral necrosis above and below. 4. (4) The close similarity between spinal meningo-myelopathy occurring as a primary lesion in the CNS on the one hand and its occurrence secondary to intracranial tuberculous meningitis or to vertebral caries on the other is stressed.