CENTRAL-NERVOUS-SYSTEM ABNORMALITIES IN COMPLEX REGIONAL PAIN SYNDROME (CRPS) - CLINICAL AND QUANTITATIVE EVIDENCE OF MEDULLARY DYSFUNCTION

Objective: Sensory and motor abnormalities are common among patients w ith complex regional pain syndrome (CRPS). The purpose of the present study was to define and characterize these abnormalities and to develo p a hypothesis regarding the area of the central nervous system from w hich they derive. Design: Data were acquired from study subjects using clinical examination and quantitative assessment of neurological func tion. Subjects were divided into four groups. CRPS patients were diffe rentiated into two groups based on the presence or absence of sensory deficit on the face to clinical examination. The other two groups were composed of patients with other chronic pain syndromes and normal ind ividuals without chronic pain or disability. Clinical and quantitative data were compared between groups. Patients: One hundred forty-five C RPS patients, 69 patients with other pain conditions, and 26 normal in dividuals were studied. Results: A high incidence of trigeminal hypoes thesia was observed in CRPS patients. CRPS patients with trigeminal hy poesthesia manifested bilateral deficits of sensory function, with a p redominant hemilateral pattern. These patients also manifested bilater al motor weakness with a more prominent hemiparetic pattern. Both sens ory and motor deficits were greatest ipsilateral to the painful side o f the body. These features differed significantly from those of CRPS p atients lacking clinical trigeminal deficit, other pain patients, and normals. A lower cranial nerve abnormality (sternocleidomastoid weakne ss) and a myelopathic feature (Hoffman's reflex) were more common in C RPS patients with trigeminal hypoesthesia. Conclusions: Nearly half of CRPS patients had abnormalities of spinothalamic, trigeminothalamic, and corticospinal function that may represent dysfunction of the medul la. One-third of the remaining CRPS patients had neuroimaging evidence of spinal cord or brain pathology. The majority of CRPS patients in t his study have measurable abnormalities of the sensory and motor syste ms or neuroimaging evidence of spinal cord or brain dysfunction.