liver Flashcards
(243 cards)
Describe the drug metabolism of aspirin
Phase I:
- Hydrolysis reaction:
Aspirin + H2O —> Salcylic acid + Ethanoic acid
Phase II:
- Conjugated with glycine or glucuronic acid
- Forms a range of ionised products which can be excreted
What is the metabolism reaction of alcohol
ADH = alcohol dehydrogenase
ALDH = aldehyde dehydrogenase
Ethanol—ADH—> acetaldehyde—ALDH—> Acetate —> CO2 + H20
Functions of the liver
(ADMIReS)
Albumin
Detoxification
Metabolism of carbs and billirubin
Immunity (Kuppfer cells)
Regulation of oestrogen levels
e
Storage (vitamins ADEK, Fe, Cu, fat)
Liver function tests (LFTs) - markers of liver function
- Bilirubin (mainly unconjugated)
- Albumin
- Prothrombin time (PT/INR)
Direct markers of liver damage
- Highun conjugated bilirubin
- Low albumin
- High PT/INR
Enzymes that show liver damage is likely
- AST and ALT
- AST:ALT usually around 1
If your AST levels are too high, it might be a sign of an injury affecting tissues other than the liver. High ALT levels may mean you have a liver injury.
Bilirubin metabolism
1 – Creation of Bilirubin
Reticuloendothelial cells are macrophages which are responsible for the maintenance of the blood, through the destruction of old or abnormal cells. They take up red blood cells and metabolise the haemoglobin present into its individual components; haem and globin. Globin is further broken down into amino acids which are subsequently recycled into new rbcs.
Meanwhile, haem is broken down into iron and biliverdin, a process which is catalysed by haem oxygenase. The iron gets recycled to rbcs, while biliverdin is rapidly reduced (bilverdin reductase) to create unconjugated bilirubin.
2 – Bilirubin Conjugation
In the bloodstream, unconjugated bilirubin binds to albumin to facilitate its transport to the liver. Once in the liver, glucuronic acid is added to unconjugated bilirubin by the enzyme glucuronyl transferase. This forms conjugated bilirubin, which is more soluble. This allows conjugated bilirubin to be excreted into the duodenum in bile.
3 – Bilirubin Excretion
Once in the colon, colonic bacteria deconjugate bilirubin and convert it into urobilinogen. Around 80% of this urobilinogen is further oxidised by intestinal bacteria and converted to stercobilin and then excreted through faeces. It is stercobilin which gives faeces their brown colour.
Around 20% of the urobilinogen is reabsorbed into the bloodstream as part of the enterohepatic circulation. It is carried to the liver where some is recycled for bile production, while a small percentage reaches the kidneys. Here, it is oxidised further into urobilin and then excreted into the urine.
What is the name of the cells responsible for fibrosis?
Stellate
Functions of the peritoneum
In health:
- Visceral lubrication
- Fluid and particulate absorption
In disease:
- Pain perception
- Inflammatory and immune response
- Fibrinolytic activity
Risk factors for biliary tract disease
- Female
- Fat (BMI 30+)
- Forty (+)
- Fertile (pregnant or many children)
- Fair
also:
- Family history
- Fatty liver disease (non-alcoholic)
- T2DM
- Haemolytic conditions
Symptoms of ascending cholangitis
Charcot’s triad:
- RUQ pain
- High fever
- Jaundice
Reynold’s pentad:
- Charcot’s triad + altered mental state + hypotension
Diagnosis of ascending cholangitis
- FBC: leukocytosis
- LFT: high conjugated hyperbilirubinaemia
- Abdo ultrasound for CBD dilation and gallstones
- MRCP: diagnostic
Treatment of ascending cholangitis
- ERCP (bile duct clearance)
- Laproscopic cholecystectomy once stable to prevent recurrence
- Consider risk of sepsis
- Empiricle while waiting Abx - co-amoxiclav
MRCP and ERCP
MRCP = Magnetic resonance cholangio-pancreatography
ERCP = Endoscopic retrogade cholangio-pancreatography
Murphy sign
- RUQ tenderness, ask patient to take a breath in while pressing RUQ
- Will wince or stop inspiring normally in cholecystitis
Symptoms of cholecystitis
- RUQ pain
- Fever
- Tender gallbladder
- Referred pain to tip of right shoulder (phrenic)
- Murphy sign positive
Diagnosis of cholesystitis
- FBC: leukocytosis + neutrophilia
- LFT: normal
- Abdo ultrasound shows thickened gallbladder wall 3mm≤
and stones/sludge in and fluid around gallbladder
Treatment for cholecystitis
- Surgery within 1 week, typically done within 72 hours
- via laproscopic cholecystectomy
- Until then: IV fluids, analgesia, antibiotics if necessary, nothing by mouth
Complications of cholecystitis
- Sepsis
- Gallbladder empyema
- Gangrenous gallbladder
- Perforation
What are gall stones made from?
- Cholestrol (80%)
- Pigment
- Or mixed
Symptoms of gallstones
- Colicky or sharp pain
- Fever
- Jaundice
- Dietary upset
Worse after a fatty meal, may come in episodes
Diagnosis of gall stones
Bloods:
- Alanine transaminase
- Bilirubin
- Amylase
Then:
First line: Abdominal ultrasound to identify gallstones
Or: MRCP (MRI scan) or CT abdomen & pelvis
Aetiology of gall stones
- Cholesterol supersaturation (diet, hormones)
- Genetic (gallbladder motility)
- Haemoglobin turnover (haemolytic anaemia, cirrhosis, sickle cell)
10% of people have gallstones
And they acount for 30% of all acute presentations
Management of gall stones if not treating directly/straight away
- NSAIDs for mild pain
- IM diclofenac for severe pain
- Change lifestyle
- Decrease fat in diet