Cerebrospinal fluid levels of myelin basic protein-like material and soluble interleukin-2 receptor in multiple sclerosis.

The presence, level and disease activity relationships of soluble interleukin-2 receptor (sIL-2R) in the cerebrospinal fluid (CSF) of multiple sclerosis (MS) patients are unresolved. We measured CSF immunoreactive myelin basic protein (MBP), a marker of acute myelin damage, and sIL-2R levels in the CSF from 11 patients with active relapsing remitting (RR) MS, five with stable RR MS, eight with chronic progressive (CP) MS, five with other neurologic diseases, and three normal controls. No measurable (less than 100 units/ml) sIL-2R was present in any of the samples. Conversely, MBP levels were elevated in the active RR group compared to the other four groups. These results indicate that, at the sensitivity of assays currently available, levels of CSF sIL-2R do not correlate with the diagnosis or disease activity of MS.

Peroneal nerve repetitive nerve stimulation test: its value in diagnosis of myasthenia gravis and Lambert-Eaton myasthenic syndrome.

We have developed a repetitive nerve stimulation (RNS) technique for the peroneal nerve. Normal limits for the decremental responses for the anterior tibialis and extensor digitorum brevis muscles are 6-21% at the low rate of stimulation and 44-70% at the high rate of stimulation. These values exceed the normal limits for other commonly tested muscles. This may be due to the lower safety factor for neuromuscular transmission for the anterior tibialis and extensor digitorum brevis muscles. We present 4 cases in which the peroneal nerve RNS test was crucial for the diagnosis of the limb-girdle form of MG or LEMS. Thus, we conclude that, in a small number of patients with neuromuscular transmission disorders, the peroneal nerve RNS test is needed for confirmation of disease.

The accessory nerve repetitive nerve stimulation test: a valuable second-line test in myasthenia gravis.

The diagnostic usefulness of the accessory nerve repetitive nerve stimulation (RNS) test was evaluated in 100 patients with myasthenia gravis (MG). The test was easy to perform and reliable at the low rates of stimulation. A higher diagnostic sensitivity was found in the accessory nerve RNS test than in the ulnar nerve RNS test on either the abductor digiti quinti or flexor carpi ulnaris muscles, especially in mild generalized MG. Diagnostic sensitivity was significantly increased when RNS test results for three muscles were combined, especially in mild generalized MG and sero-positive MG. In a small number of cases only the ulnar or accessory nerve RNS test was abnormal. There was a good correlation between electrophysiological and clinical severity of MG in the accessory nerve RNS test Thus, we conclude that the accessory nerve RNS test is a valuable second-line test and its greatest usefulness is in cases of mild generalized MG.

Primary respiratory failure as the presenting symptom in Lambert-Eaton myasthenic syndrome.

Myasthenia gravis can present with rapid respiratory failure as the first manifestation of disease. In the Lambert-Eaton myasthenic syndrome (LEMS), such a manifestation has rarely been reported. We are reporting a patient who developed respiratory failure as the first manifestation of LEMS without associated carcinoma.