Anthony C. Breuer

Ischemic optic neuropathy A complication of cardiopulmonary bypass surgery

Ischemic optic neuropathy followed cardiopulmonary bypass surgery in the postoperative period in 7 of 7685 consecutive procedures. The visual loss was unilateral in four patients and bilateral in three and there was little improvement. This ischemic infarction of the optic nerve disk was attributed to hypotension, hypothermia, and activation of certain complement factors by the bypass procedure.

Amyotrophic lateral sclerosis Effects of acute intravenous and chronic subcutaneous administration of thyrotropin‐releasing hormone in controlled trials

We performed double-blind crossover trials to assess the effects of thyrotropin-releasing hormone (TRH) on amyotrophic lateral sclerosis patients. For acute intravenous trials, 500 mg TRH or placebo with norepinephrine was given at 1-week intervals (16 patients). CSF TRH concentration increased, and clinical side effects appeared with TRH. For chronic studies, 25 mg TRH and a saline placebo were given subcutaneously every day for 3 months (25 patients). CSF TRH level increased 29-fold after a single TRH injection, and mild transient side effects occurred. Vital signs, respiratory function, semiquantitative and quantitative neurologic function, muscle strength by manual and dynamometer testing, and EMG were studied. With daily TRH, 10 patients noted subjective improvement without objective evidence, and 10 patients complained of worsening of the disease with objective decline after TRH was stopped. Statistical analysis, however, showed no beneficial effects from either acute or chronic TRH trials.

Mechanism and Frequency of Brachial Plexus Injury in Open-Heart Surgery: A Prospective Analysis

A computer-assisted prospective analysis of 531 patients undergoing open-heart operations revealed that 26 patients (5%) sustained brachial plexus injury. In 22 of the 26 patients (85%), the lesion involved the lower trunk or C8-T1 nerve roots. Electromyograms confirmed the clinical impression in 13 patients. In 19 of the 26 patients (73%), the side on which the plexus lesion was found correlated with the side of internal jugular vein cannulation. Because of the anatomical proximity of the lower trunk to the internal jugular vein and the preponderance of lower trunk lesions, we postulate that traumatic cannulation may be a major mechanism of plexus injury. Thus, the resulting syndrome of pain, dysesthesias, and hand weakness may sometimes be preventable.

Malignant lymphoma of the central nervous system: A case of primary spinal intramedullary involvement

Primary involvement of the spinal cord in malignant lymphoma is rare. Clinical and pathologic features of a case of malignant lymphoma initially involving the spinal cord and subsequently one cerebral hemisphere are reported and the medical literature reviewed. If malignant lymphoma of the central nervous system is diagnosed by means of brain biopsy examination, radiotherapy of any coexisting intramedullary spinal cord lesion of undetermined cause should be considered.

Radicular vessels are the most probable source of needle-induced blood in lumbar puncture. Significance for the thrombocytopenic cancer patient

Despite knowledge of the bleeding hazard to thrombocytopenic cancer patients undergoing lumbar puncture (LP), a retrospective analysis of physician behavior at one hospital revealed no consistent use of platelet transfusions in patients with less than 20,000 platelets/mm3 on the day of LP. A review of the literature and laboratory cerebrospinal fluid (CSF) data in two institutions, and the performance of an LP experiment revealed that: (1) Batsons epidural venous plexus is an unlikely source and spinal radicular vessels are the most probable source of needle‐induced blood in lumbar puncture; (2) the frequency of encountering needle‐induced blood at LP is high, 73% (3) the frequency of brushing a nerve root, with the associated risk of lacerating the radicular artery or vein on its surface with the bevel of the LP needle, is high and may be on the order of 26%; and (4) while the passage of an LP needle, obturator in place, through a blood filled vein may carry red cells into a red cell‐free medium, this does not always occur. These new considerations argue for more consistent adherence to the already published recommendation of platelet transfusion immediately prior to LP in patients with low platelets. This issue is of particular relevance to the rapidly growing population of thrombocytopenic cancer patients with extended survival on multiple chemotherapeutic regimens requiring lumbar puncture.

Amount and Speed of Fast Axonal Transport in Diabetes

Abnormalities in axonal transport have been observed in human and experimental diabetes and may be related to the pathogenesis of diabetic neuropathy. Axonal transport has previously been evaluated by indirect methods. In this study, direct-measurement techniques were applied (with computer-enhanced video-recorded images) for the first time to evaluate intra-axonal organelle speed and frequency (the amount of organelle traffic) in both the anterograde fast component (AFC) and retrograde fast component (RFC) of axonal transport in diabetic nerve. Sciatic nerve and dorsal and ventral nerve roots were studied in the animal model of insulin-dependent diabetes (BB/Wistar rat) and sciatic nerve in the non-insulin-dependent (streptozocin-induced) model of diabetes (STZ-D rat). STZ-D rats were studied at 1 mo, and BB/Wistar rats were studied at 1 and 2 mo of diabetes duration. Statistically significant decreases in peripheral axon organelle speed were found only for RFC at 1 mo of diabetes in both the BB/Wistar (8.1%) and STZ-D (5.4%) rats. The difference was no longer significant in BB/Wistar rats at 2 mo of diabetes. This recovery suggests that the underlying abnormality is reversible. No differences were seen in AFC of any axons, and the only other difference seen was a 5.1% decrement in RFC at 2 mo in the ventral roots. No significant difference was observed in any group for organelle frequencies. Other factors should be considered to explain the decrease in materials transported in accumulation studies. The transient deficits in RFC speed observed remain of undetermined significance in the pathogenesis of diabetic neuropathy.