Nutritional consequences of amyotrophic lateral sclerosis

Abstract

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disorder characterized by degeneration of the motor neurons in the brain, brain stem, and spinal cord. Clinically, there are dysphagia and dysarthria from bulbar involvement and muscle weakness with atrophy that result in profound and progressive weakness, respiratory failure, and death within 3 to 4 years from onset. Malnutrition is present in a substantial proportion of patients, with energy or caloric deficiency predominating. The malnutrition is of multifactorial origin, resulting not only from decreased energy intake but also from increased caloric expenditure related to physical activity and hypermetabolism. Several techniques detect malnutrition, ranging from simple anthropometry to the estimation of body composition to define loss of muscle and body fat, indirect calorimetry to demonstrate increased resting energy expenditure, and doubly labeled water methodology to show increased total daily energy expenditure. Malnutrition has several adverse consequences, including accelerated disease progression and early death. This chapter describes an algorithmic approach to nutritional care in ALS, preferably undertaken through regular visits to a multidisciplinary clinic with staffed experienced healthcare providers. This chapter also provides recommendations for reliably estimating energy intake and expenditure needs of patients to ensure energy balance.