Encephalopathy Notes

NOTES NOTES ENCEPHALOPATHY GENERALLY, WHAT IS IT? PATHOLOGY & CAUSES ▪ Abnormal brain structure/function ▪ Permanent/reversible brain injury due to direct injury/other illness SIGNS & SYMPTOMS ▪ Altered mental status ▫ Irritability, agitation, confusion, somnolence, stupor, coma, psychosis, delirium ▪ Seizure, myoclonus, asterixis, ataxia, tremor DIAGNOSIS DIAGNOSTIC IMAGING Brain imaging (CT scan, MRI, etc.) ▪ Changes indicative of Wernicke–Korsakoff syndrome (e.g. shrunken mammillary bodies) LAB RESULTS Blood studies ▪ Complete blood count (CBC), 572 OSMOSIS.ORG comprehensive metabolic panel (CMP) ▫ ↑ ammonia, ↑ transaminases, ↑ prothrombin time, hyper/hypoglycemia Cerebrospinal fluid (CSF) ▪ Determine underlying cause, rule out other causes OTHER DIAGNOSTICS Electroencephalogram (EEG) ▪ High-amplitude low-frequency, triphasic waves TREATMENT MEDICATIONS ▪ Anticonvulsants ▫ Individuals with seizures due to encephalopathy OTHER INTERVENTIONS ▪ Careful monitoring, supportive measures (e.g. IV fluids, nutritional support)

Chapter 74 Encephalopathy BERIBERI osms.it/beriberi PATHOLOGY & CAUSES ▪ Thiamine (vitamin B1) deficiency ▫ Decreased intake/inability to absorb thiamine RISK FACTORS ▪ Common in individuals who are alcoholic, malnourished, elderly COMPLICATIONS ▪ “Wet beriberi” ▫ Cardiomegaly, cardiomyopathy, heart failure SIGNS & SYMPTOMS ▪ Nystagmus, ataxia, ophthalmoplegia (triad of Wernicke–Korsakoff syndrome), confusion ▪ Wet beriberi: tachycardia, dyspnea, edema ▪ Dry beriberi: peripheral neuropathy, confusion, pain; AKA Wernicke–Korsakoff syndrome DIAGNOSIS DIAGNOSTIC IMAGING CT scan/MRI ▪ Changes indicative of Wernicke–Korsakoff syndrome (e.g. shrunken mammillary bodies) OTHER DIAGNOSTICS ▪ History ▫ Alcoholism/low nutritional state TREATMENT MEDICATIONS ▪ IV thiamine supplementation ▫ Avoid glucose before thiamine if alcoholic; can precipitate encephalopathy HEPATIC ENCEPHALOPATHY osms.it/hepatic-encephalopathy PATHOLOGY & CAUSES ▪ Brain injury due to toxic metabolites; not removed by liver due to liver dysfunction ▪ Accumulation of toxic metabolites (e.g. ammonia), byproduct of nitrogen metabolism ▪ Ammonia detoxification in astrocytes → glutamine accumulation → osmotic stress → swelling ▪ Other injuries (e.g. alkalosis, metabolic abnormalities, medications, bleeding, infection) → hepatic encephalopathy OSMOSIS.ORG 573

SIGNS & SYMPTOMS ▪ Mental status: confusion, poor concentration, stupor, coma ▪ Neuromuscular: asterixis, rigidity, hyperreflexia ▪ Graded by severity ▫ Grade I: mild; short attention span; mood, sleep problems ▫ Grade II: moderate; decreased energy, slurred speech, tremors ▫ Grade III: severe; confusion, stupor, anxiety ▫ Grade IV: coma DIAGNOSIS DIAGNOSTIC IMAGING T1-weighted MRI ▪ Hyperintensity of globus pallidus LAB RESULTS OTHER DIAGNOSTICS ▪ Psychometric tests ▫ Inhibitory control test (ICT); mental status changes ▪ History ▫ Liver disease, altered mental status EEG ▪ High-amplitude low-frequency, triphasic waves TREATMENT MEDICATIONS ▪ Lactulose ▫ Decrease absorption of ammonia ▪ Rifaximin ▫ Kill bowel flora that produce ammonia OTHER INTERVENTIONS ▪ Nutritional support ▫ Limit protein intake ▪ Blood tests ▫ ↑ ammonia REYE SYNDROME osms.it/reye-syndrome PATHOLOGY & CAUSES ▪ Encephalopathy, liver failure associated with salicylate use in children with viral illness ▪ Rare syndrome in children ages 4–12; associated with aspirin use during viral infection (e.g. varicella, influenza A/B) ▪ Uncoupling of oxidative phosphorylation reactions ▪ Oxidative phosphorylation in mitochondria fails → liver damage → nitrogen-containing toxins not removed from blood → ammonia accumulates in blood → crosses blood- 574 OSMOSIS.ORG brain barrier → swelling, oxidative damage to astrocytes → brain inflammation, edema → encephalopathy SIGNS & SYMPTOMS ▪ Five stages 1. Quiet, sleepy, vomiting 2. Stupor, seizures, decorticate response, intact pupillary reflex 3. Possible coma, decerebrate response, absence of pupillary reflex 4. Coma, absence of deep tendon reflex 5. Death

Chapter 74 Encephalopathy DIAGNOSIS LAB RESULTS ▪ Blood studies ▪ ↑ ammonia, ↑ transaminases, ↑ prothrombin time, hyper/hypoglycemia OTHER INTERVENTIONS ▪ Hyperventilation ▫ Manage cerebral edema ▪ Careful monitoring, supportive measures (e.g. IV fluids) OTHER DIAGNOSTICS ▪ History ▫ Viral illness, aspirin use TREATMENT MEDICATIONS ▪ Mannitol, glycerol ▫ Manage cerebral edema Figure 74.1 The histological appearance of the liver of a child who died from Reye syndrome. The hepatocytes have accumulated fat droplets which causes a pale appearance. OSMOSIS.ORG 575