Transcript clinical-biochmeistry-of-liver-disease-4th-med-Dec

Recommended Reading
Lecture Notes in Clinical Biochmesitry 7th Edition
G Beckett, S Walker, P Rae, P Ashby (Blackwell publishing)
Clinical Chemistry 5th Edition
W J Marshall, S K Bangert (Pubslished by Mosby)
An illustrated Colour text - Clinical Biochmeistry 3rd edition
Alan Gaw et al (Churchill Livingston)
Handbook of Clinical biochmeistry 1st Edition
R Swaminathan (Oxford University Press)
Clinical Chemistry in diagnosis and treatment
Philip Mayne (Edward Arnold)
A Guide to Diagnostic Clinical Chemistry 3rd Edition
Walmsely & White (Blackwell)
Clinical Biochemistry of Liver Disease
Dr Vivion Crowley
Consultant Chemical Pathologist
St James’s Hospital
December 2006
What are the functions of the liver?
•Key role in intermediary metabolism
e.g. gluconeogenesis, glycolysis, ketogeneis, lipid synthesis
•Protein synthesis – including many plasma proteins and blood
clotting factors
•Bile secretion and role in digestion
•Primary site of xenobiotic detoxification -drug and toxin metabolism
•Ureagenesis - ? Role in acid-base balance
What are Liver Function Tests (LFTs)
Total Bilirubin
-Conjugated vs. Unconjugated
-Anion transport
Alkaline Phosphatase (ALP)
-Reference range varies with age – higher in childhood
and adolescence
-Isoenzymes e.g. bone, liver, intestine, malignancy
-Bile flow
Gamma-glutamyl transferase (GGT)
-Sensitive indicator of liver disorder
-Cholestasis
-Induced by many drugs and toxins e.g. C2H5OH,
pheytoin, barbiturates, ? statins
Transaminases
-Alanine aminotransferase (ALT)
-Aspartate aminotransferease (AST)
-ALT is more liver specific
-AST is also found in cardiac and skeletal muscle
-Hepatocellular integrity
Albumin
- Plasma transport protein
-Assesses Protein synthesis in liver
Prothrombin time
-Extrinsic pathway of coagulation
-Reflects protein synthetic function
What role do LFTs in clinical management ?
Detecting the presence of liver disease
Indicating the broad diagnostic category of the liver disease
Monitoring treatment
Specialised Liver-related tests
Viral Hepatitis Screen – A, B, C etc.
Autoimmune Hepatitis screen – AMA, ASMA,
Serum protein electrophoresis
α1- antitrypsin
 α fetoprotein (AFP)
Transferrin Saturation/Ferritin/HFE Genotyping
Caeruloplasmin, Plasma/Urine Copper
Ultrasound scan, CT, MRI
Biopsy
Clinical History
C2H5OH Hx
Family Hx – Haemochromatosis, Wilson Disease,
Drug Hx – What medication is the patient taking?
Travel Hx – Recent travel, Blood transfusions
Bilirubin production and metabolism
UDP
Glucoronosyl
transferase
Hyperbilirubinaemia
•Jaundice evident with Bilirubin levels 35-70μmol/L
•Normally 95% of plasma bilirubin is unconjugated
Unconjugated - prehepatic
*(No bilirubinuria)
Conjugated – Hepatic/posthepatic
(Bilirubinuria)
•Haemolyis
•Resolving haematoma
•Gilbert’s Syndrome
•Crigler-Najjar syndrome
•Hepatocellular diseases
•Cholestatic diseases
•Dubin-Johnson**
•Rotor’s syndrome**
*Except in Nephrotic syndrome
**Benign congenital conjugated hyeprbilirubinaemia
Gilbert’s Syndrome
Present in 5% of the population
•Males > females
•Genetic origin
– insertion of TA in promoter region of UGT-1A gene
•Exacerbated by fasting and illness
•Confirm conjugated hyperbilirubinaemia
•Rule out haemolysis FBC, Reticulocyte count
•Rule out underlying liver disease -
Causes of neonatal jaundice
Unconjugated bilirubin level > 300μmol/L may be associated
with Kernicterus (brain damage due to uptake of unconjugated bilirubin)
Patterns of LFTs
Hepatocellular
•Predominant elevation in AST/ALT –
Cholestatic
•Predominant elevation in ALP with GGT ± Bilirubin
Mixed
•Elevation in both AST/ALT, and ALP/GGT ± Bilirubin
Causes of a Hepatocellular Pattern of LFTs
Marked elevations in ALT/AST > x5 URL
(patient likely to be symptomatic)
•Viral hepatitis
•Ischaemic hepatitis
•Autoimmune hepatitis
•Drug/toxins e.g. alcoholic hepatitis
Mild/Moderate elevations in ALT/AST < x5 URL
(patient may be asymptomatic)
•Chronic Hepatitis
•ALD
•NAFLD/NASH – associated with obesity, T2DM, Hyperlipidaemia
•Metabolic liver disease - HH, WD, A1AT
•Drugs
•Autoimmune LD
Approach to an asymptomatic patient with elevated ALT/AST
Elevated AST/ALT
Repeat test
Normal
Still Elevated
Check CK
Elevated
Normal
Likely Liver Aetiology
Drug Hx etc
Viral serology
AI heptistis screen
Fe/TIBC/Ferritin/HFE genotyping
Caeuruloplasmin if < 40 ty
A1AT
Coeliac screen
Ultrasound scan
MRI/CT
Bx
Causes of a Cholestatic Pattern of LFTs
Elevated ALP and GGT ± Bilirubin, relative to transaminases
Intrahepatic
(Bilirubin not elevated)
Extrahepatic
(Bilirubin elevated)
•Medications
•TPN
•Sepsis
•Postoperative
•PBC
•Alcoholic hepatitis
•Liver mets
•Pregnancy-related
•CCF
•Cholelithiasis (CBD)
•Malignancy – HOP,
•Primary sclerosing cholangitis
GGT is useful in differentiating Liver as a cause of elevated ALP
An approach to the patient with isolated elevation in ALP
Elevated ALP
Normal
?bone, placenta,
Intestine etc.
What is GGT?
Elevated
US/CT/MRI
Biliary dilation
No abnormality
Focal mass
Medications
PBC
-AMA
Consider other
causes
Specialised investigations
Other LFTs
Serum ammonia
-used for investigation of hepatic encephalopathy
-lacks sensitivity and specificity
-useful fo investigation of urea cycle disorders
Serum LDH
-included in LFTs in SJH
-5 isoenzymes – heart, erythrocytes, skel mus, liver, others
-not specific for liver - ? role in ischaemia-related abnormal LFTs
-useful in monitoring certain malignancies e.g. B-cell lymphoma
- “not really a LFT”
Reference Ranges for LFTs
Biochemistry Department, St James’s Hopsital
Albumin
Bilirubin
35-50 g/L
<17 μmol/L
ALP*
40-120 IU/L*
AST
ALT
7-40 IU/L
7-35 IU/L
GGT
10-55 IU/L
* NB: Reference Range is age related
Case 1
24 yr old male
Insurance medical showed abnormal LFTs ? Cause
Albumin
Bilirubin
42 (35-50 g/L)
38 (<17 μmol/L)
ALP
98 (40-120 IU/L)
AST
ALT
30 (7-40 IU/L)
28 (7-35 IU/L)
GGT
37 (10-55 IU/L)
What further tests are indicated?
What is the most likely cause of raised Bilirubin?
Case 2
35 yr old female with a 4/52 hx of
-malaise, anorexia, upr abdominal pain, ?haematuria
-O/E Icteric
Alb
Bilirubin
35
126
ALP
250 (40-120)
AST
1459
ALT
2009
GGT
331
What further investigations are indicated?
What fraction of her bilirubin is elevated and how does this
impact on her “haematuria”?
Case 3
You are phoned about the following results and asked to
comment on the ALP which appears to be elavated?
Pt is a 17 yr old male – clinical details
Alb
Bilirubin
ALP
46
12
220 (40-120)
AST
ALT
GGT
20
20
9
“still growing”
What is the likely cause for the elevated ALP?
Which isoenzyme is increased?
Case 4
48yr old female is attending a lipid-clinic
-polygenic hypercholesterolaemia
-On atorvastatin 20mg/d for 2 years
-C/o tired fatigue, malaise
Alb
TBilirubin
ALP
42
8
250 (40-120)
AST
ALT
GGT
38
26
220
LFTs measured 6/12 previously were normal
What further investigations would you perform?
What is the differential diagnosis?
Case 5
37 yr old male is referred to a lipid clinic with ? Mixed hyperlipidaemia
(Chol 7.0 Trigs 5.2)
-BMI 35, WC=120cm
-Normotensive
-Otherwise clinically well
Fasting Glucose
Alb
6.8 mmol/L
38
TBili
ALP
AST
15
82
58
ALT
GGT
72
67 (<55)
What further investigations would you suggest and why?
Case 6: Background
Phonecall from a GP regarding LFTs
72yr old female with discomfort in R hypochondrium
No other hx of note
Not on medications
No C2H5OH
Case 6: LFTs
Alb (35-50)
Tbili (3-17)
AST (7-40)
ALT (7-35)
Alk Phos (40-120)
GGT (5-40)
LDH (230-450)
CK (34-170)
28/4
3/5
39
10
113
39
6
106
95
372
930
495
82
352
874
426
Case 6: Further investigations
Mixed cholestatic and hepatocellular liver disease
Fe, TIBC, TS% - all normal
Hepatic Antibody screen – negative
Ultrasound of Upr Abdomen recommended
Gallstones diagnosed
Case 7: Background
•47 yr old male
•Hx – malaise and ?icterus (confirmed in sclera)
•No recent hx C2H5OH excess or medication
6/5
12/5
Alb
45
43
TBili
181
242
Alk Phos
454
408
GGT
813
428
AST
344
75
ALT
707
Case 7: Dx
•Predominant hepatitic picture
•Resolving to cholestatic LFTs
Probable acute viral hepatitis
Case 8
24 yr old male
-Vague hx of feeling unwell, also wt loss >7Kg
-? Eating disorder/psychiatric illness
7/3
4/4
Alb
51
50
Tbili (3-17)
93
48
Conj Bili
9
Alk Phos
74
84
GGT
14
18
AST
25
23
Case 8: Further Investigations
FBC and Reticuloctye count – normal
Viral Hep screen – normal
Hep antibody screen – normal
U/S – normal
Biochmeical Dx:
-unconjugated Hyeprbilirubinaemia (Gilbert’s syndrome)
-confirmed by genetics
Case 9: Why the elevated LFTs?
52 yr old male
No medical hx of note
Not on regular medications
Non-specific hx
Routine Bloods done by GP
“Family Hx IHD” written on request form
Case 9: Results
Fasting Lipid and Glucose – unremarkable
AST = 243, LDH = 1525 (230-450)
GGT = 85 (10-55) other LFTs normal
GP surprised at the raised AST
? Further investigations
Case 9: Further Investigations
ALT = 50 (7-35)
CK 1191 (29-195)
CK-MBmass = 132 (<12)
CK-MB fractionation 10% (<6%)
Case 9: Dx
GP practice contacted:
-Informed by Registrar that results were of concern
-needed to be communicated to GP
-1day later Consultant phoned to see if action had been taken
-Pt contacted and advised to present to A/E SJH
Troponin T = 3.25 (<0.01)
Acute Coronary Syndrome (Acute MI)
PTCA and stenting performed
Paracetamol Overdose
•Hepatic necrosis observed within 36-72 hours
•Accumulation of breakdown product NAPQI
Early diagnosis and treatment of
paracetamol OD is essential
•Ideally before 12 hours post ingestion
•N-acetylcysteine (Parvolex) is an effective agent
Iron Overload Syndromes
Primary:
Hereditary Haemochromatosis (HH)
Secondary:
Non HH Cirrhosis
Ineffective erythropoiesis – sideroblastic anaemia, Thalassaemia
Multiple transfusions
Bantu siderosis
Porphyria Cutanea Tarda (PCT)
Hereditary Haemochromatosis
Autosomal recessive
Mutations in HFE gene
-C282Y
-H63D
93% associated with homozygosity C282Y +
6% associated with compound heterozygosity C282Y + H63D
1% No mutations identified
Clinical presentation of HH
Males > females
Usually in middle age
Clinical presentation caused by iron accumulation in
Liver – fatty change
Cirrhosis
Pancreas – Diabetes
Heart – dilated cardiomyopathy
Joints – arthropathy
Pituitary – secondary hypogonadism (males > females)
Testses – primary hypogonadism (rarer)
Parathyroid - hypocalceamia
Diagnosis of HH
•Increased Transferrin Saturation (Plasma Fe/TIBC)
55% - genotype
45-55% - may consider genotype
•Increased Ferritin
•HFE genotype
•Liver Biopsy
•Liver Iron content
Figure A
H63D
C282Y
1
2
1
3
2
3
1.
Homozygous mutant
1.
Homozygous mutant
2.
Heterozygous
2.
Heterozygous
3.
Wild type (normal)
3.
Wild type (normal)
Case Example : Haemochromatosis
51yr old male
Total protein
Total Bilirubin
Alk Phos
GGT
AST
ALT
Serum Fe
TIBC
Transferrin sat
Ferritin
71
14
82
39
44
92
38
41
93%
1,316
HFE genotype C282Y homozygous –Hereditary Haemochromatosis
Wilson disease
Autosomal recessive
Associated with mutations in ATP7B
(Cu transporting P type ATPase)
Clinical presentation – Children and adults usually < 40 years
•CNS – extrapyramidal system, Kayser-Fleischer rings in cornea
•Liver – fatty liver, cirrhosis,acute fulminant hepatic failure
•Kidney, Haemolytic anaemia
Dx:
Low plasma caeruloplasmin
Increased Urinary Cu excretion (Penicillamine Challenge Test)
Liver Bx – measure Cu content