Response of serum enzymes and other biochemical constituents to strenuous exercise in control subjects and patients with motor neurone disease

Amyotrophic lateral sclerosis: relationship between serum creatine kinase level and patient survival

Various laboratory tests have been used to predict the survival of patients with amyotrophic lateral sclerosis (ALS). The serum creatine kinase (CK) level is frequently elevated in patients with ALS. This study evaluates the relationship between serum CK elevation and survival in patients with ALS and points to a lack of correlation. Thirty patients with ALS, who ranged in age from 21 to 73 years, were followed up from 7 to 57 months. All patients had neurologic and psychiatric evaluations, electromyographic examinations, and serum CK measurements. The CK level was elevated in 50% of the patients. On follow-up, 20 patients had died; ten of these had had elevated CK levels. The 3-year survival from the date of the examination was 47% for patients with elevated CK levels and 40% for patients with normal levels. This difference did not have statistical significance (p greater than 0.43).

Elevation of creatine kinase in amyotrophic lateral sclerosis. Potential confusion with polymyositis

Serum creatine kinase (CK) levels were recorded in 100 patients with amyotrophic lateral sclerosis (ALS). CK concentrations were elevated in 43% of the patients, with a mean level of 240 U/liter and a range of 59-1,327 U/liter (male normal less than 95 U/liter, female normal less than 59 U/liter). All patients with elevated CK had muscle weakness. Seven patients were initially misdiagnosed as having polymyositis and given high dose corticosteroids without clinical benefit, prior to the diagnosis of ALS. Such diagnostic confusion can be avoided by an awareness that CK levels cannot be used to reliably differentiate between ALS and primary muscle disease such as polymyositis.