lecture section...septic encephalopathy
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Lecture section...Septic encephalopathy http://yassermetwally.com http://yassermetwally.netTRANSCRIPT
Professor Yasser Metwallywww.yassermetwally.com
Septic encephalopathy
IntroductionImpairment of cons., including coma, often
occurs in association with sepsis Occur in a range of 8–70% of septic patientsMay as an early sign of sepsis The term "septic encephalopathy" :
acute confusional episodes or other significant cognitive abnormalities that develop during sepsis
as an entity that cannot be explained by hepatic or renal dysfunction, hypotension, or hypoxia
Imply poor prognosis , higher mortality
Etiology and Pathophysiology(1) Most likely multifactorial Underlying mechanisms only been defined in
parts Disseminated cerebral microabscesses
infecting organisms and/or their toxins do not directly cause encephalopathy
Systemic inflammation resulting from infection or other causes action of inflammatory mediators on the brain
, cytotoxic response of brain cells
Etiology and Pathophysiology(2)Sepsis activate a variety of inflammatory
cascade , → SIRSInflammatory efffector cell
neutrophil , macrophage , plt , endothelial cell etc
Inflammatory mediators Cytokines , lipid products , complement etc
Free radicals
Etiology and Pathophysiology (3)Free radicals
damage RBC and limit O2 delivery to brain Inflammatory mediators
impair mitochondrial function and O2 extraction by the brain
destroy BBB perimicrovessel edema disruption of astrocyte endfeet aromatic a.a enter brain parenchyma and disturb NT
Ultimately, extensive neuronal injury *
Diagnosis (1)Evaluating depressed cons. in critically ill p`ts
(1) Receiving sedative and narcotic drugs (2) Head injury , intracranial event e.g.
cerebrovascular causes(3) Metabolic derangements :
Sugar , electrolytes (Na , Ca) , acid-base balance (acidemia , hypercapnia) , oxygenation (hypoxia , hypotention) , hepatic encephalopathy , uremic encephalopathy , septic encephalopathy , alcohol or drug
Diagnosis (2)Evaluating coma in surgical patients
【 Failure to awaken after surgery 】 v.s. 【 Alteration of cons. that develops after an
asyrnptomatic interval 】Post-op hyponatremia
Free water administered under ADH↑ & renal f. ↓ Acute uremic encephalopathy
major heart surgery or major surgery complicated by sepsis or involves considerable GI repair
perioperative acute renal failure renal hypoperfusion and nephrotoxicity
TreatmentCurrently, there is no treatment !!some patients with sepsis cons. remain
unresponsive after the associated life threatening conditions are controlled marked hypotension ↑ inotropic agent ischemic damage brain Ultimately, extensive neuronal injury in
pathophysiology of septic encephalopathy
Prognosis
JAMA. 1996 Feb 14;275(6):470-3(prospective study in 50 sepsis patients )
Severity of septic encephalopathy (graded by GCS ) correlated with mortality
JAMA. 1996 Feb 14;275(6):470-3 (prospective study in 50 sepsis patients )
Bacteremia was more common in encephalopathic patients ( by altered mental status grading )
P`ts with bacteremia more commonly have an altered mental status, which is associated with a higher mortality
PrognosisSeveral lab. values showed a linear
relationship with the severity of encephalopathy, including WBC, Po2, BUN/Cr, Bil, ALP, serum albumin and K. → one feature of more widespreading MOF
Disturbance of protein metabolism plasma and brain a.a were deranged aromatic a.a. levels correlated with APACHE
II scores and mortality
Ongoing studyCSF protein content was mildly elevated
(60–85 mg/dL) EEG is a more sensitive detector of CNS
dysfunction than is the clinical examination and also is a powerful predictor of survival EEG provides a large amount of data that are often difficult to quantify