20.7.2013 Flashcards
Precipitating factors for hepatic encephalopathy
Hypokalemia Alkalosis(diarrhoea,diuretics) Constipation High protein diet SBP Opioids Sedative hypnotics Hematemesis Shunt,TIPS ALF progressive hepatocellular dysfunction
Substances elevated in hepatic encephalopathy
Ammonia False Neurotransmitters Mercaptans Myoinositol Neurosteroids allopregnanenolone Tetrahydrodeoxycorticosterone
First sign and symptom of hepatic encephalopathy
Sign-constructional apraxia
Symptom-altered sleep pattern
Dietary management in hepatic encephalopathy
Replacement of animal protein by vegetable protein
Diet rich in branched chain amino acids
Goal of lactulose therapy
2-3 loose stools per day
Side effects of neomycin
Renal toxicity
Ototoxicity
Side effects of metronidazole
Peripheral neuropathy
Trace mineral supplement helpful in hepatic encephalopathy
Zinc
Effectiveness of beta-blocker therapy
25% reduction in resting pulse rate
Calculation of Hct from Hb
Hb*3
Neck flexors
Strap muscles
Sternocleidomastoid
Neck extensors
Longus colli
Asterexis is seen in which grades of hepatic encephalopathy
Grade 2 and 3
Grade 1 hepatic encephalopathy
Sleep reversal
Mild confusion
Irritability
Tremor
Grade 2 hepatic encephalopathy
Disorientation
Lethargy
Inappropriate behaviour
Asterixis
Grade 3 hepatic encephalopathy
Severe confusion
Somnolence
Aggressive behaviour
Asterixis
EEG in hepatic encephalopathy
Slow,high amplitude,triphasic waves
Role of blood ammonia level in hepatic encephalopathy
Neither sensitive and nor specific
Initial dose of lactulose
15-45ml bd or qid
Contraindications to oral lactulose
Ileus
Bowel obstruction
Dose of rifaximin
400mg PO tid
Structures affected in hepatic encephalopathy
Cerebellum
Basal ganglia
Causes of elevated blood ammonia level
GI bleeding Urea cycle disorders Proline metabolism disorders Diuretics Alcohol Narcotics Valproate CKD Cigarette Muscle exertion and ischemia High body temperature Tourniquet use while blood sampling High protein diet
Role of arterial ammonia level
Elevated levels(more than 150mg/dl) are predictive for cerebral edema and brain herniation in acute liver failure
Name of grading system of hepatic encephalopathy
West haven
Highly specific test for diagnosis of hepatic encephalopathy
PSET
portosystemic encephalopathy syndrome test
Neuromuscular findings in Grade 1 hepatic encephalopathy
Tremor
Incoordination
Neuromuscular findings in grade 2 hepatic encephalopathy
Asterixis
Ataxic gait
Slow and slurred speech
Neuromuscular findings in grade 3 hepatic encephalopathy
Muscular rigidity Clonus Nystagmus Babinski Hyporeflexia
Latest tests in hepatic encephalopathy
Critical flicker frequency test
MRS
TAPIR(MR T1 mapping with partial inversion recovery)
Indication for lactulose enema in hepatic encephalopathy
Pts at risk of aspiration
First line agents in Rx of hepatic encephalopathy
Non absorbable disaccharides
Rx of mild hepatic encephalopathy in pts with cirrhosis and adult onset diabetes
Acarbose
Increases saccharolytic to proteolytic bacteria ratio
Drugs that enhance ammonia excretion in urine
Sodium benzoate
Sodium phenylbutyrate
Sodium phenylacetate
Why zinc is beneficial in hepatic encephalopathy?
Zinc increases the activity of Ornithine transcarbomylase
Artificial liver
MARS
molecular adsorbant recirculating system
Drug useful in grade 3 and 4 hepatic encephalopathy
Flumazenil
Amino acids useful in Rx of hepatic encephalopathy
LOLA
L-Ornithine L-Aspartate
Efficacy comparable to lactulose
What is MARS?
Extra corporeal albumin dialysis
Subtle signs of hepatic encephalopathy are seen in _____ % of pts with cirrhosis
70
Diff btw hepatic encephalopathy due to ALF and cirrhosis
Brain Edema plays a prominent role in HE due to ALF
Categories of hepatic encephalopathy
Type A- ALF
Type B- portosystemic Bypass without hepatocellular disease
Type C- cirrhosis
Histologic change in hepatic encephalopathy in cirrhosis
Alzheimer’s type 2 astrocytosis(absent in ALF)
Neurotoxic substances in hepatic encephalopathy
Ammonia Manganese Short chain fatty acids False Neurotransmitters Mercaptans GABA
False Neurotransmitters
Octapamine
Tyramine
Betaphenylethanolamine
Important site of ammonia detoxification in cirrhosis
Skeletal muscle
Contain Glutamine synthetase
Skeletal muscle wasting in chronic cirrhosis increases hyperammonemia
Neurosteroid hypothesis in hepatic encephalopathy
Ammonia and manganese increase the expression of peripheral type Benzodiazepine receptor in astrocytes
Stimulation of PTBR results in increased production of neurosteroids
Neurosteroids stimulate GABA receptor
Grade zero hepatic encephalopathy
Covert hepatic encephalopathy
Causes for Asterixis
HE
uremia
Pulmonary insufficiency
Barbiturate toxicity
Cause of fetor hepaticus
Mercaptans
MRI finding in hepatic encephalopathy
Hyperintensity of Globus pallidus due to manganese deposition
Rx of HE pt with severe agitation
Haloperidol
Why vegetable proteins are preferred in HE?
Contain dietary fibre
Decreased aromatic amino acids
Rifaximine?
Non absorbable derivative of rifampin
Use of rifaximine
Travellers diarrhoea
HE
Mechanism of action of LOLA
Stimulates urea cycle
Both aminoacids are substrates for glutamate transaminase,increased synthesis of glutamate
MOA of sodium benzoate
Combines with glycine to form hippurate which is excreted renally
MOA of sodium phenylbutyrate
Converted to phenylacetate which combines with Glutamine to form phenylacetylglutamine
Drug that can be given to improve sleep in hepatic encephalopathy pts
Hydroxyzine 25mg at bedtime
Urine osmolality in hyponatremia
Less than 100 mosm/L
Specific gravity less than 1.003
