On this page
Study tools
Write your answer
Saved on this device. No marking — you are the marker.
Stem
A 58-year-old man with known alcohol-related cirrhosis (Child-Pugh B, MELD 18) is brought to the ED by his wife. She reports that over the last 48 hours he has become increasingly drowsy, confused about the date, and on the morning of admission he did not recognise his son. He has been constipated for the last 4 days. He takes spironolactone 100 mg daily and had a fall in the bathroom 3 days ago without loss of consciousness. On examination: GCS 13 (E4 V3 M6), temperature 37.9°C, pulse 96, BP 108/64, RR 18, SpO2 95% on air. He is icteric with spider naevi, palmar erythema, ascites and a palpable spleen tip. He is disoriented for time, has bilateral asterixis and constructional apraxia (cannot draw a clock). Capillary glucose is 4.2 mmol/L. There are no focal neurological deficits.
Questions
a) What is the clinical diagnosis, the grade (West Haven), and three immediate investigations to confirm the precipitant? (3 marks)
Diagnosis: acute overt hepatic encephalopathy (Type C — cirrhosis) — a reversible syndrome of impaired brain function in a patient with advanced liver disease, with bilateral asterixis, constructional apraxia, disorientation and signs of chronic liver disease.
Grade: West Haven grade II (lethargy, disorientation, asterixis present — overt HE).
Immediate investigations to find the precipitant: (1) diagnostic paracentesis of ascites for cell count and culture — spontaneous bacterial peritonitis is the commonest precipitant (define SBP by ascitic PMN over 250 cells/mm³); (2) full septic screen — blood cultures, urine culture, chest X-ray (temperature 37.9°C raises infection); (3) CT brain (non-contrast) — he had a fall 3 days ago, is coagulopathic (cirrhosis), and confusion could be a subdural haematoma rather than (or in addition to) HE. Also send U&E (hyponatraemia/hypokalaemia), FBC, LFT, INR, venous ammonia (on ice).
b) Outline the immediate management in the first hour. (4 marks)
- ABCDE — protect airway (he is drowsy, GCS 13; nurse lateral, monitor for aspiration).
- Capillary glucose already done (4.2 mmol/L — normal); give parenteral thiamine (Pabrinex — one pair of ampoules IV) before any IV glucose as he is alcoholic, to prevent Wernicke.
- IV access, bloods (U&E, FBC, LFT, INR, ammonia on ice, blood cultures); start IV fluids cautiously with balanced crystalloid.
- Septic screen and diagnostic paracentesis; if PMN over 250 give cefotaxime 2 g IV BD plus IV albumin 1.5 g/kg day 1 then 1 g/kg day 3 (to prevent hepatorenal syndrome).
- CT brain to exclude subdural.
- Start lactulose 30 mL via NGT every 1–2 hours until 2–3 soft bowel motions daily (he is constipated — likely precipitant or co-precipitant), then titrate down.
- Stop sedatives (avoid benzodiazepines unless alcohol withdrawal is diagnosed).
c) Describe the mechanism of action of lactulose and state the endpoint by which the dose is titrated. (2 marks)
Lactulose (a non-absorbable synthetic disaccharide) acts by three mechanisms: (1) osmotic catharsis — reduces gut transit time and contact of ammonia with mucosa; (2) acidification of the colon — bacterial fermentation produces lactic and acetic acid, lowering colonic pH to under 5, converting diffusible NH3 to non-absorbable NH4+ (ion trapping) so ammonia is excreted in stool; (3) favouring urease-negative flora (suppressing Klebsiella, Proteus).
Endpoint: two to three soft bowel motions per day — NOT a target serum ammonia level.
d) What is the recommended secondary prophylaxis to prevent recurrence, and what referral should be made on discharge? (1 mark)
Continue lactulose (titrated to 2–3 soft stools/day) and add rifaximin 550 mg twice daily (Bass 2010 NEJM: 58% reduction in breakthrough HE when added to lactulose). A first episode of overt HE carries 1-year mortality of 40–50% — refer for liver transplant evaluation.