Incidence of aspiration pneumonia in ALS in Olmsted County, MN.

Aspiration pneumonia is believed to be an uncommon complication of amyotrophic lateral sclerosis (ALS). However, the incidence of aspiration pneumonia and its contribution to morbidity and mortality are unknown in ALS. All cases of ALS from Olmsted County, Minnesota from 1990 to 2005 were reviewed. Baseline demographics were noted for all cases. Dates of diagnosis, PEG tube placement, death and survival status were also noted. All cases of aspiration pneumonia were identified. Forty cases of ALS were identified over the 15-year period. The incidence rate was 1.7 cases per 100,000 person years. There was an overall mean survival of 26 months from diagnosis. Aspiration pneumonia occurred in five (13%) cases. There was a mean survival of two months following aspiration pneumonia. The strongest risk factor for aspiration pneumonia was nursing home residence with a relative risk of 7.1 (p = 0.02) We conclude that the incidence rates and demographics of our ALS population have remained stable over time. Aspiration pneumonia occurs in a minority but is associated with a high mortality. ALS subjects residing in nursing homes are at the greatest risk.

Effect of referral bias on assessing survival in ALS.

We assessed the effect of referral bias on patients with ALS treated at our medical center. A total of 132 subjects were treated by our center over the past 3 years. The referral population had a median survival of 29 months compared to 18 months for the local population (p = 0.007). Referral bias should be addressed when assessing the efficacy of self-selected therapies in the setting of a tertiary ALS clinic.

Carpal tunnel syndrome with normal nerve conduction studies.

The utility of electrodiagnostic testing in the evaluation of carpal tunnel syndrome (CTS) has been questioned. We studied patients who met the clinical criteria for CTS and compared patients who had normal nerve conduction studies (NCS) with patients who had abnormal NCS. We found that 25% of the CTS patients without confounding neurologic disorders had normal NCS with median palmar nerve stimulation. Patients with abnormal NCS were older and heavier and had more clinical features of CTS. NCS results could not be predicted accurately from clinical features by use of logistic regression models. This was especially true in clinically borderline cases. NCS did not predict the outcome of conservative management. We concluded that NCS provide independent information in the evaluation of suspected CTS, especially when fewer clinical criteria are present, but that NCS are not helpful in predicting the outcome of nonsurgical management.

Mitochondrial myopathy and complex III deficiency in a patient with a new stop-codon mutation (G339X) in the cytochrome b gene.

A 19-year-old woman complained of life-long exercise intolerance and had chronic lactic acidosis. Neurological examination was normal, but muscle biopsy showed cytochrome c oxidase-positive fibers and marked complex III deficiency. Sequence analysis showed a novel stop-codon mutation (G15761A) in the mitochondrial DNA (mtDNA)-encoded cytochrome b gene, resulting in loss of the last 41 amino acids of the protein. By PCR/restriction fragment-length polymorphism (RFLP) analysis, the G15761A mutation was very abundant (73%) in the patient's muscle, barely detectable (less than 1%) in her urine, and absent in her blood; it was also absent in muscle, urine and blood from the patient's mother. This mutation fulfills all accepted criteria for pathogenicity.