Bruce A. Evans

Plasma exchange in polyneuropathy associated with monoclonal gammopathy of undetermined significance

BACKGROUND Polyneuropathy associated with monoclonal gammopathy of undetermined significance (MGUS) has been treated with plasma exchange, intravenous immune globulin, and chemotherapy, but the effectiveness of these treatments remains uncertain. METHODS We randomly assigned 39 patients with stable or worsening neuropathy and MGUS of the IgG, IgA, or IgM type to receive either plasma exchange twice weekly for three weeks or sham plasma exchange, in a double-blind trial. The patients who initially underwent sham plasma exchange subsequently underwent plasma exchange in an open trial. RESULTS In the double-blind trial, the average neuropathy disability score improved by 2 points from base line (from 62.5 to 60.5) in the sham-exchange group and by 12 points (from 58.3 to 46.3) in the plasma-exchange group (P = 0.06). A similar difference was observed in the weakness score, a component of the neuropathy disability score (improvement, 1 and 10 points, respectively; P = 0.07). After treatment the summed compound muscle action potentials of motor nerves were 1.2 mV lower (worse) than at base line in the sham-exchange group and 0.4 mV higher (better) in the plasma-exchange group (P = 0.07). The greater degree of improvement with plasma exchange was equal in magnitude to or greater than the difference between not being able to walk on the heels or toes and being able to perform these activities. Changes in the vibratory detection threshold, summed motor-nerve conduction velocity, and sensory-nerve action potentials did not differ significantly between the treatment groups. In the open trial, in which patients who initially underwent sham exchange were treated with plasma exchange, the neuropathy disability score (P = 0.04), weakness score (P = 0.07), and summed compound muscle action potentials (P = 0.07) improved more with plasma exchange than they had with sham exchange. In both the double-blind and the open trial, those with IgG or IgA gammopathy had a better response to plasma exchange than those with IgM gammopathy. CONCLUSIONS Plasma exchange appears to be efficacious in neuropathy associated with MGUS, especially of the IgG or IgA type.

Lumbosacral plexus neuropathy

We describe 10 cases of lumbosacral plexus neuropathy in which no underlying condition was discovered on initial evaluation or on follow-up examination after an average of 6 years. The patients presented with pain and weakness. Recovery was delayed and often incomplete. When the lower plexus is involved, it may be confused with disk disease manifesting as “sciatica.” This syndrome may be a counterpart to the well-described idiopathic brachial plexus neuropathy.

High-grade carotid stenosis detected before general surgery: Is endarterectomy indicated?

Article abstract—The risk of stroke in unselected patients and patients with a carotid bruit undergoing general anesthesia and surgery is very low. The incremental risk related to known carotid stenosis is uncertain. The authors studied 284 patients with ultrasound studies before general surgery, 224 of whom demonstrated carotid stenosis. Carotid stenosis was related to a perioperative risk of stroke of approximately 3.6%. Greater degrees of stenosis did not confer significantly higher risk. Although higher than in the unselected population, this risk does not appear sufficient to mandate prophylactic endarterectomy.

Pseudoulnar palsy from a small infarct of the precentral knob

Discrete stroke in the parietal lobe or the white matter of the angular gyrus, ventroposterior thalamus, and in the posterior limb of the internal capsule can mimic peripheral nerve lesions.1,2 Recently, the motor hand area has been localized to a knob on the precentral gyrus by functional MRI studies.3 We describe a case in which diffusion-weighted imaging confirmed the observation that the precentral knob is the motor hand area. A 74-year-old right-handed man, a retired physician, awoke with right-hand weakness and numbness. He noted difficulty holding a glass of water and numbness involving digits III through V. There was no history of previous stroke. His risk factors for stroke included previous episodes of atrial fibrillation and noninsulin-dependent diabetes. Examination showed weakness (Medical Research Council [MRC] grade, 4/5) of the long finger flexors …

Factors Affecting Survival and Occurrence of Stroke in Patients With Transient Ischemic Attacks

OBJECTIVE To assess the predictive value of a series of demographic and clinical variables for stroke and survival in a population after a first transient ischemic attack (TIA). DESIGN Cox proportional hazards regression analysis was used to determine the association of various demographic and clinical factors with survival and stroke in 330 residents of Rochester, Minnesota, who had an initial TIA with first medical attention within 120 days during the period 1955 through 1979. MATERIAL AND METHODS We investigated several demographic, diagnostic, and treatment variables, including initial clinical manifestations (pure sensory TIA and unilateral carotid hemispheric TIA), to estimate the significant (P < or = 0.01) predictors of survival and of stroke. Follow-up was limited to 10 years. RESULTS Relative survival for patients with a first TIA was 94% at 1 year and 87% at 5 years after first medical attention. Three interactions were significant predictors of survival: (1) age at TIA and gender (young women had the best survival and older women had the worst survival), (2) systolic blood pressure and congestive heart failure (patients with low systolic blood pressure and congestive heart failure had the worst survival), and (3) calendar year of onset and diabetes mellitus (survival was worst for patients with diabetes during the early years of the study). Only age was a significant independent predictor of stroke after TIA (hazards ratio, 1.45 per 10 years). CONCLUSIONS Estimating risks of stroke and death after TIA on the basis of demographic and clinical variables without reference to the mechanism of TIA is of limited clinical utility. Age is the most significant such predictor. Interactions that reflect comorbidity, such as diabetes, blood pressure abnormalities, or heart disease, may affect survival but not the risk for occurrence of stroke.

Structural and Biochemical Effects of Essential Fatty Acid Deficiency on Peripheral Nerve

The effect of postweaning essential fatty acid (EFA) deficiency on the peripheral nerve was studied in groups of rats. At 325 days, the characteristic biochemical changes of EFA deficiency were present in isolated peripheral myelin, although to a lesser degree than reported in non-neural tissues. There was no significant difference between control and deficient groups in number or size distributions of myelinated fibers (MFs) in muscle and sensory nerves, in the incidence of teased fiber abnormalities, in rates of axonal transport of dopamine-β-hydroxylase and acetylcholinesterase, or in conduction velocity and compound action potentials of peripheral nerve in vivo or in vitro. Four weeks after a standard sciatic crush injury, the median MF diameter in regenerated peroneal nerves was significantly smaller in EFA-deficient rats than in control rats, but this difference was no longer significant at 18 weeks. At 18 weeks, EFA-deficient and control regenerated nerves showed similar myelin periodicity and relationship of axonal area to number of myelin lamellae. We conclude that acquired EFA deficiency in the rat leads to biochemically abnormal peripheral myelin, but that this state is unaccompanied by clinical, physiological, or morphological evidence of neuropathy.

Patent foramen ovale causing stroke in an elderly woman.

A patent foramen ovale (PFO) was fully documented as the cause of a cerebral infarction in a 78-year-old woman, with asymptomatic deep venous thrombosis and pulmonary embolism as secondary causes. The report is unique in view of the patients age and lack of history or clinical evidence of cardiac or pulmonary disease, thromboembolic disease, or systemic embolism at or before the stroke. This case emphasizes the etiologic role of PFO in cryptogenic strokes even in elderly patients with no obvious clinical risk factors for paradoxical embolism.