Septic Autocannibalism

Abstract

Forty-six patients with surgical sepsis were studied prospectively until death or survival to evaluate the effect of exogenous metabolic support on the observed plasma substrate levels and on the differential endogenous utilization of branch chain amino acids. There were no effects of administered glucose or colloid load. The administered amino acid load had little effect on substrate levels in patients who died; but significantly effected the observed levels of glycine, isoleucine, and methionine in patients who survived. Evidence is presented which suggests that fatal sepsis is associated with an increased release of endogenous valine and isoleucine into plasma, as well as increased plasma levels of tyrosine, proline, and methionine. These abnormalities are highly correlated with the increased levels of plasma alanine and occur at a time when the nonsurviving septic patient manifests a tendency toward reduced oxygen consumption and abnormal vascular tone relations--the septic B state. These data are consistent with the hypothesis that increased muscle protein catabolism is occurring with a differential utilization of branch chain amino acids and increased use of leucine and isoleucine and reduced use of valine. This autocannibalism of muscle mass appears to be the source of the increased plasma alanine and is little influenced by administered amino acid support in the absence of control of the septic process.

Muscle protein metabolism during sepsis

“…The L-arginine: NO pathway [S] is involved in a variety of physiological processes in the cardiovascular and nervous system where NO is generated via constitutive Ca2+-dependent NO synthases [5,6]. In the vasculature, the NO synthase releases relatively small amounts of NO in response to receptor stimulation and shear stress and maintains a vasodilator tone [5,7].…”

“…In the vasculature, the NO synthase releases relatively small amounts of NO in response to receptor stimulation and shear stress and maintains a vasodilator tone [5,7]. An inducible Ca2+-independent NO synthase is expressed in phagocytic and other cells after activation by endotoxin and/or cytokines.…”

“…If allowed to continue uncontrolled, however, muscle breakdown will result in muscle wasting, fatigue and delayed recovery. T h e term 'autocannibalism' has been used to illustrate the serious consequences of muscle proteolysis during severe and protracted sepsis [5].…”

The Impact of Neonatal Illness on Nutritional Requirements: One Size Does Not Fit All

“…While preterm and term infants spend most of their hospitalization days in “growth mode”, ie, convalescing and preparing for discharge, a significant portion of their time is also spent being ill. Bodies of literature from adult and pediatric critical care demonstrate that illness significantly alters metabolism, and by definition, nutrient requirements (8, 9). Furthermore, recommendations for the nutritional management of the IUGR infant are not distinguished from appropriate for gestational age (AGA) preterm infants, yet metabolic rates and the capacity for nutrient utilization inevitably differ (10).…”

Septic shock

“…It is no longer viewed as a perfusion defect but is considered a primary metabolic disturbance, with shock and hypoperfusion as much a consequence as a contributing cause. Also, cultures are negative in more than one third of cases of multiple organ system failure, 14 so the continued presence of the invading organism clearly is not required to 72 SEPTIC SHOCK • VOL86/N03/SEPTEMBER 1, 1989/POSTGRADUATE MEDICINE Because the source of infection in septic shock is often not evident, empirical broad-spectrum antibiotic therapy is indicated until culture results are known. maintain the distrtbutive defect.…”