Summary of investigation and assessment of suspected hepatic encephalopathy
| Investigation/clinical assessment | ||
| West-Haven criteria | ||
| Covert encephalopathy | ||
| Grade 0 (minimal HE) | Animal naming test | Examples of psychometric/neurophysiological tests |
| Critical flicker frequency | ||
| Stroop test | ||
| Psychometric Hepatic Encephalopathy Score | ||
| EEG | Poor sensitivity and specificity in minimal HE | |
| Grade 1 | Trivial lack of awareness, impaired attention span, altered sleep, euphoria or depression | |
| Overt encephalopathy | ||
| Grade 2 | Asterixis, minimal disorientation to time/place, behaviour/personality change, lethargy, ataxia/slurred speech | |
| Grade 3 | Marked confusion/stupor, gross disorientation, somnolence but responsive to verbal stimuli | Should be used in conjunction with the Glasgow Coma Scale |
| Grade 4 | Coma | |
| Exclusion of differentials (if alternative diagnosis suspected)/precipitating factors | ||
| Brain MRI | Hippocampal atrophy suggests Alzheimer’s disease. Small vessel changes suggest vascular dementia. | |
| Ammonia | Not required routinely. A normal value brings HE diagnosis into question and other potential causes of confusion | |
| Electrolytes | Hypokalaemia common HE precipitant—aim potassium >4 | |
| Confusion/infection screen (including CT head) | Useful in possible delirium or acute intracranial event suspected | |
| Vascular-phase abdominal CT | Exclude large spontaneous portosystemic shunts (can be drivers of HE in otherwise well-compensated patients) | |
EEG, electroencephalogram; HE, hepatic encephalopathy.