chapter  22
22 Pages

Intracranial Lesions and Tremor

I. Introduction 307

II. Neoplastic Lesions 308

A. Resting and/or Parkinsonian Tremor 308 B. Intention and Cerebellar Tremor 309

C. Holmes Tremor 310

D. Other Tremor Types 310

III. Infectious Intracranial Lesions 311

IV. Vascular Lesions 312

V. Demyelinating Lesions 317

VI. Iatrogenic Etiologies 318

References 319

I. INTRODUCTION

A tremendous number of reports of brain lesions resulting in tremor have been

described in the literature (1-52). Advances in imaging and other diagnostic

techniques have improved the recognition and reporting of lesions that result

in tremor. As a result of this improved technology, a myriad of diseases and path-

ologies from many intracranial regions have been reported to result in almost

every type of tremor. Although most intracranial lesions still follow the

“general rules” regarding localization, pathophysiology, and corresponding

tremor phenomenology such as basal ganglia lesions resulting in a contralateral

resting 4-7 Hz tremor, cerebellar lesions resulting in a slow ipsilateral intention

tremor, and midbrain lesions resulting in a contralateral resting, postural, and

intention tremor, there have been occasional exceptions to the established

notion of tremor pathophysiology. This should, however, be cautiously inter-

preted. Localization by imaging may be only as good as the technological

modality used. An ipsilateral tremor from a large basal ganglia lesion does not

definitively exclude a small contralateral lesion missed by a computed tomogra-

phy (CT) scan. Magnetic resonance imaging (MRI) may better expose a lesion’s

anatomical devastation. Functional (or “pressure”) effects of the lesions on

contiguous or contralateral areas that more intuitively explain a patient’s

tremor phenomenology may not be fully appreciated. Only recent case reports

have considered the “vascular effects” of intracranial lesions on distant brain

regions through magnetic resonance angiography (MRA). With regard to intra-

cranial infectious and neoplastic lesions, tremor resulting from slow infiltration,

co-infection, edema, distant metastasis, and antibody/paraneoplastic phenomena, may be missed or misinterpreted despite contrast enhancement.