Diagnostic yield by testing small fiber function in patients examined for polyneuropathy.

We assessed the diagnostic yield of adding quantitative sensory testing to the standard work-up for polyneuropathy in unselected patients. All patients aged 18 to 70 years referred to our department for electrodiagnosis with a tentative diagnosis of polyneuropathy and symptoms complying with predefined criteria were included in the study. We performed near nerve conduction studies in 4 nerves and determined heat and cold detection thresholds on hand and foot with a Thermotest (Somedic AB, Sweden). In order to uncover CNS diseases, somatosensory-evoked potentials were recorded in patients with abnormal quantitative sensory testing and normal nerve conduction studies. A total of 198 patients completed the study and 149 were considered to have polyneuropathy. Twenty-five patients remained undiagnosed and in 24 patients, other diseases were responsible for the symptoms. Of the patients with either polyneuropathy or no other diagnosis, 76% (n = 174) had abnormal nerve conduction. Abnormal cold sensation, heat sensation or abnormality in at least 1 of these and normal nerve conduction were found in 14, 12 and 17 patients. Of the 174 patients, 86% (95% CI 80-90%) had an abnormality in at least 1 of the tests (i.e. abnormal nerve conduction and/or abnormal quantitative testing of temperature sensation). In conclusion, quantitative testing of temperature sensation improves the diagnostic yield in patients examined for chronic polyneuropathy.

Evaluation of patients with symptoms suggestive of chronic polyneuropathy.

OBJECTIVES: The aim of this study was to determine the diagnostic yield and to describe the spectrum of diagnosis encountered by evaluation of patients with symptoms suggestive of chronic polyneuropathy. METHODS: We prospectively evaluated 198 patients referred to a department of neurology with symptoms suggestive of polyneuropathy. The evaluation included nerve conduction studies with near-nerve technique, quantitative examination of temperature sensation, blood tests, chest x-rays, and skin biopsies as well as diagnostic tests for differential diagnoses. RESULTS: Polyneuropathy was found in 147 patients, alternative diagnoses in 25, and 26 remained undiagnosed. The etiology of polyneuropathy could not be identified in 25% of the patients with polyneuropathy. In the remaining 75%, the cause of neuropathy was diabetes and/or alcohol abuse (41%), monoclonal gammopathy of undetermined significance (5%), drugs (5%), connective tissue disease (3%), and a number of less frequent conditions. A previously undiagnosed condition was found in 30% of the patients with polyneuropathy. CONCLUSION: Evaluation of patients with symptoms suggestive of polyneuropathy reveals a high fraction of patients with previously undiagnosed conditions both in patients ending up with a polyneuropathy diagnosis and those without this diagnosis.

A presenilin-1 Thr116Asn substitution in a family with early-onset Alzheimer's disease.

Mutation in the presenilin-1 (PS-1) gene at chromosome 14q24.3 is the most common cause of autosomal dominant early-onset Alzheimer's disease. Here, we report a novel missense mutation in the presenilin-1 gene found in a three-generation Danish family with autopsy-verified early-onset Alzheimer's disease. Two affected first-degree relatives in two generations were found to be heterozygous for a cytosine to adenine transversion at the second position of codon 116, which changes the amino acid at that position from threonine to asparagine. This conservative amino acid substitution occurs in an evolutionary highly conserved region of the PS-1 protein and is associated with onset of the disease between age 35 and 41 years and 4-8 years' duration of the disease. Analysis of amyloid beta-protein (A beta) deposition in brain specimens from one affected family member showed predominance of A beta 42(43). Onset and progression of the disease were very similar in two sibs homozygous for the epsilon 3 allele and the epsilon 4 allele, respectively, of the polymorphic apolipoprotein E locus. The lack of effect of the high risk epsilon 4/epsilon 4 genotype on the disease in this family corroborates and extends previous observations that the presence of one copy of the epsilon 4 allele does not modulate PS-1 associated Alzheimer's disease.

[Ballism in systemic lupus erythematosus]. / Ballisme ved systemisk lupus erythematosus.

A case of systemic lupus erythematosus (SLE) with ballism is presented. The movement disorders, as a group, account for approximately 2% of the neurological and psychiatric symptoms of central nervous system (CNS) involvement in SLE, and more than any of the other neuro-psychiatric manifestations they tend to precede the diagnosis of SLE. Ballism and other rare movement disorders are not included in the 1982 revised American Rheumatism Association criteria for SLE. Being aware of the correlation between CNS disease and more severe SLE, one should assess therapeutic intervention critically.