Quality of life after septic illness

Abstract

Purpose

The study was undertaken to evaluate the quality of life of survivors of septic illness.

Materials and Methods

A questionnaire survey of survivors of septic illness (experimental group) and acute myocardial infarction (control group) was conducted using information from the Adult Neuropsychological History and the Sickness Impact Profile forms. Eight patients diagnosed with sepsis (using the Bone et al 1992 criteria [Bone RC, Sprung CL, Sibbald WJ. Crit Care Med 1992;20:724-726]) and 15 patients diagnosed with acute myocardial infarction participated in the study.

Results

On the Sickness Impact Profile, greater difficulty with work was reported in the sepsis group than in the cardiac control group (P < .04). When retired individuals were excluded from the analysis, individuals in the sepsis group reported more symptoms on the sensory, physical, and behavior sections of the Adult Neuropsychological History form and greater difficulty with sleep and rest, emotional behavior, body care and movement, and physical and psychosocial functioning on the Sickness Impact Profile. As well, more individuals in the sepsis than the control group endorsed symptoms related to problem solving, concentration, memory, sensory, and physical ability.

Conclusions

Individuals surviving sepsis may have problems with physical, sensory, emotional, and cognitive functioning that become most apparent when involved in more challenging activities, such as working.

Introduction

Sepsis is a systemic reaction to microorganisms in the blood or tissues that is frequently encountered in modern tertiary care hospitals. This systemic reaction is produced by inflammatory mediators or cytokines [1]. More than 70% of septic patients develop an encephalopathy or diffuse disturbance in cerebral function [2]. A retrospective study of 69 patients with fever and positive microbial cultures revealed that the following factors directly correlated with degree of brain dysfunction: certain electroencephalographic abnormalities; the presence of acute respiratory distress syndrome; elevation of peripheral white blood count; elevated serum levels of alkaline phosphatase, bilirubin, creatinine, phosphate, potassium, and urea; and mortality rate [2]. Wijdicks and Stevens [3] found a strong correlation of severe hypotension with the development of encephalopathy. However, we have certainly encountered patients with septic encephalopathy who did not have severe hypotension. About 50% of severely encephalopathic patients died in the context of multiple organ failure.

In a clinical-pathologic study of 12 patients who died after a protracted course of sepsis and septic encephalopathy [4], we found a number of brain abnormalities, including microabscesses especially in the cerebral cortex, microscopic ischemic lesions, occasional petechiae, and glial changes in keeping with metabolic encephalopathy. Studies of cerebrospinal fluid withdrawn during life showed an elevation of protein concentration, in keeping with a breakdown in the blood-brain barrier [4]. Others have found numerous central nervous system microabscesses, particularly in the cerebral cortex, in series of patients who died of sepsis [5]. The lesions documented on neuropathologic examination were too small to be seen on magnetic resonance imaging or computed tomographic scans. These findings led us to propose several potential mechanisms for septic encephalopathy that are not mutually exclusive as follows: direct infection of the brain (microabscesses), metabolic dysfunction, altered microcirculatory perfusion of the brain, altered blood-brain barrier permeability, or iatrogenic causes [6]. Wilson and Young [7] have proposed that sepsis may lead to irreversible brain damage/neuronal death by causing regional brain ischemia, free radical damage/oxidative stress, excitotoxicity through glutamate, and apoptotic mechanisms.

The structural lesions encountered in brains of patients who died of sepsis raised the possibility of persisting neurologic deficits in survivors. We thus conducted a follow-up study of individuals 1 to 4 years after surviving a septic illness to determine whether they might be experiencing persistent cerebral dysfunction that would affect their quality of life. This knowledge would help us to understand the effect of septic illness on the brain, to appreciate the potential impact on our patients' quality of life, and to establish necessary outpatient follow-up services. The definition of quality of life provided by McSweeney et al [8] was used for the purposes of this study. Quality of life encompasses 4 dimensions: (1) emotional functioning, including mood changes and other psychiatric symptoms; (2) social role functioning, including employment, home management, and social and family relationships; (3) activities of daily living, that is, self-care skills and mobility; and (4) the ability to engage in enjoyable hobbies and other recreational pastimes.

Previous research has shown that the quality of life in individuals surviving sepsis is different from that of the general US population [9] and may be improved by the administration of hydrocortisone during the illness [10]. However, corticosteroids may contribute to the development of critical illness myopathy, which could diminish the quality of life, although the clinical evidence is based principally on observational studies [11]. No study has specifically explored potential cognitive and emotional outcome in survivors of sepsis, although this has been studied in other patients after an intensive care stay, including patients surviving acute respiratory distress syndrome (ARDS), characterized by severe acute lung injury and arterial hypoxemia. Acute respiratory distress syndrome may occur in response to various direct or indirect insults to the lungs, including sepsis, trauma, massive transfusions, and multiorgan dysfunction. Investigators have found persistent functional disability 1 year postdischarge [12], impaired general health, psychosocial problems, a poor return to work rate [13], [14], and cognitive sequelae [15], [16], [17], [18] in survivors of ARDS and after an intensive care stay.

The current study uses a comparison group that has also experienced a life-threatening illness and more specifically attempts to assess the presence of long-term changes in quality of life that may be attributable to the effects of sepsis on brain function. Using a comparison group helps control for factors related to the effects of a special care unit stay alone. A cardiac control group was chosen because these individuals have been through a serious life-threatening illness requiring admission to a special care unit and survived. Furthermore, there is abundant evidence that both sepsis and myocardial infarction produce an inflammatory response in the body [1], [7], [19], [20], [21].

Self-report measures were used in this study as a preliminary step in determining whether sepsis patients and/or their family members report poorer quality of life and greater cognitive and/or emotional dysfunction than individuals in a control group. The total score and scales of the Sickness Impact Profile [22], [23] have been shown by other investigators to correlate with the performance on neuropsychologic tests of patients with head trauma [24], pulmonary disease [25], and mild cerebrovascular disease [26]. This would suggest a positive relationship between complaints reported on the Sickness Impact Profile and cognitive performance.