Jerry G. Kaplan

Sensory neuropathy from pyridoxine abuse. A new megavitamin syndrome

We describe seven adults who had ataxia and severe sensory-nervous-system dysfunction after daily high-level pyridoxine (vitamin B6) consumption. Four were severely disabled; all improved after withdrawal. Weakness was not a feature of this condition, and the central nervous system was clinically spared. Although consumption of large doses of pyridoxine has gained wide public acceptance, this report indicates that it can cause sensory neuropathy or neuronopathy syndromes and that safe guidelines should be established for the use of this widely abused vitamin.

Taxol produces a predominantly sensory neuropathy

Taxol, a plant alkaloid with promise as an antineoplastic agent, produced a predominantly sensory neuropathy in 16 of 60 patients treated in two phase I trials. This neuropathy occurred only at taxol doses greater than 200 mg/m2. Symptoms typically started 1 to 3 days following treatment, beginning in the hands and feet simultaneously in most patients. Electrophysiologic data suggests both axonal degeneration and demyelination. This previously undefined neurotoxic neuropathy most likely results from taxols unique ability to produce microtubule aggregation in dorsal root ganglion cells, axons, and Schwann cells.

Leptomeningeal metastases : comparison of clinical features and laboratory data of solid tumors, lymphomas and leukemias

We reviewed 63 cases of cytologically confirmed leptomeningeal metastases (LM). 31 (49%) had solid tumors 17 (27%) had leukemia and 15 (24%) had lymphoma.The most common presenting symptom was pain (76%) with radicular discomfort (58%), headache (32%), neck or back pain (17%). The predominant neurological signs were mental status abnormalities (49%), weakness (47%), seizures (14%).The mode of presentation varied with tumor type. Patients with leukemia (18%) and lymphoma (13%) tended to present frequently with LM without systemic involvement, or during periods of apparent remission (leukemia 35%, lymphoma 27%), while patients with solid tumors had established systemic metastases (90%) at time of presentation. Laboratory studies did not vary among the groups. 71% had positive cytology on the first lumbar puncture (LP) and only 8% required more than 2 LPs. The cell count was a poor predictor of positive cytology as 29% of LPs with positive cytology and 36% of all LPs had less than 4 cells/mm.We conclude that 1) LM presents with pain and seizures more frequently than has been previously recognized; 2) LM is frequently the mode of presentation in patients with leukemia and lymphoma and; 3) cytology is positive frequently in CSF specimens with normal cell counts and chemistries.

Infectious agents in spinal epidural abscesses

Of 27 cases of spinal epidural abscess, 19 were caused by bacteria, 7 by Mycobacterium tuberculosis, and 1 by Echinococcus granulosus. Blunt trauma and cutaneous infections were the most frequent preceding events in bacterial cases. Tuberculous abscess was usually the sole manifestation of reactivation of dormant tuberculosis. Drug addiction, the most common cause in young adults, was associated with gram-negative infections. Whatever the infectious agent, paraparesis for longer than 4 days led to a poor outcome. Myelography was the best diagnostic test, whereas lumbar puncture and percutaneous bone biopsy offered little specific information.

Sensory neuropathy associated with Dursban (chlorpyrifos) exposure

Chlorpyrifos (Dursban) is an organophosphate insecticide with extensive domestic and agricultural applications. It is regarded as safe for these purposes; one report of neurotoxicity is attributed to massive ingestion in a suicide attempt. We report eight people who developed peripheral neuropathy after exposure to exterminator-applied commercial Dursban; five also experienced memory loss and cognitive slowing. Evaluation failed to reveal other causes of neurologic dysfunction; symptoms recurred in one patient following accidental reexposure. We conclude that environmental contact with chlorpyrifos can cause sensory neuropathy and CNS dysfunction and that this agent should be used with caution.

Kindling in developing rats: variability of afterdischarge thresholds with age

In the kindling model, the occurrence of afterdischarges is necessary for the development of seizures. In this study, the afterdischarge thresholds of the amygdala were determined in rats of 4 different age groups, beginning with 15-day-old suckling rats. Afterdischarges were triggered in 75% of the suckling rats and in all of the rats in the older age groups. The afterdischarge thresholds varied with age, being highest in the suckling group, lowest in the 35-day-old group and intermediate in the older groups. This variability of the thresholds did not correlate with the alterations in the catecholamine levels in the amygdala that occur during maturation. The failure of 25% of suckling rats to develop afterdischarges may explain why some suckling rats do not kindle.

Gait and Balance in the Elderly: Two Functional Capacities That Link Sensory and Motor Ability to Falls

Neuromuscular function, which underlies efficient gait and balance, deteriorates with age and disease. A review of the literature and of data from the current study suggests the presence of poor gait and balance in elderly individuals who have a history of multiple falls. The tests of gait and balance are simple to perform and therefore may be widely applicable in evaluating individuals at risk of falls. Quantitative studies of motor and sensory function, vibratory sensation, and electrophysiologic studies of nerve integrity are discussed. Deteriorating motor and sensory control mechanisms appear to play an important role in falling.

Distal axonopathy associated with chronic gluten enteropathy A treatable disorder

Our experience with one patient and literature review reveals that patients with chronic gluten enteropathy and severe steatorrhea may develop a generalized peripheral neuropathy of the distal axonopathy type. Vitamin levels are usually normal, and the neuropathy appears to respond to gluten restriction.

Progressive dementia, visual deficits, amyotrophy, and microinfarcts

Data from three patients and 22 previously reported cases suggest that cerebral microinfarction causes a recognizable clinical syndrome. All cases present with stroke, followed by progressive dementia and often with visual field deficits, peripheral vascular disease, and signs of motor neuron dysfunction. The average age at onset is 45, and most patients have been men. Many patients have had valvular or ischemic heart disease; in one of our cases, mitral stenosis caused embolic microinfarcts.

Luetic meningitis with gumma Clinical, radiographic, and neuropathologic features

A 28-year-old man had headache and unilateral third-nerve palsy as the presenting features of acute syphilitic meningitis, accompanied by an asymptomatic cerebral gumma.