Recommended Reading

Lecture Notes in Clinical Biochemistry 7th EditionG Beckett, S Walker, P Rae, P Ashby (Blackwell publishing)

Clinical Chemistry 6th EditionW J Marshall, S K Bangert (Pubslished by Mosby)

An illustrated Colour text - Clinical Biochmeistry 3rd editionAlan Gaw et al (Churchill Livingston)

Handbook of Clinical biochmeistry 1st EditionR Swaminathan (Oxford University Press)

Clinical Chemistry in diagnosis and treatmentPhilip Mayne (Edward Arnold)

A Guide to Diagnostic Clinical Chemistry 3rd EditionWalmsely & White (Blackwell)

Clinical Biochemistry of Liver Disease

Dr Vivion CrowleyConsultant Chemical PathologistSt James’s Hospital

75 yr old female presented to her GP

C/O dyspepsia and “back “ pain

Background hx: •Breast Ca – Rx with mastectomy, Tamoxifen•Variegate Porphyria•Type 2 Diabetes mellitus•Subclinical Hypothyroidism

GP requested Liver Function Tests (Liver Profile)

Illustrative case History

Albumin 43 (34-48) g/L

Total Bilirubin 7 (0 – 21) umol/L

Alkaline Phosphatase 67 (35 -104) IU/L

GGT 93 (5 – 36) IU/L

Alanaine transaminase (ALT) 40 (6 – 31) IU/L

In view of abnormal LFTs the GP ordered further investigations

•Anti Smooth Muscle abs - neg•Anti Mitochondrial abs - neg

•Alpha-1 Antitrypsin 1.5 (0.9 – 2.0) g/L

•Caeuroloplasmin 26.2 (20 – 60) mg/dl

•Transferrrin Saturation 34% (15 – 45) %

•PT 14.8 (11.5 – 15.0) s

•APTT 30.4 s (25 – 35) s

Ultrasound of abdomen and pelvis

Liver-Diffuse inhomogenous somewhat echogenic texture-No focal lesion-Bile ducts not dilated

CT scan of abdomen

Liver-Normal size-Subcapsular surface of the liver has a nodular outline-Liver texture has a diffuse slightly coarse appearance

Appearances consistent with Cirrhosis

GP requested imaging studies in view of negative blood tests

Learning Point

• The only indicator for the presence of underlying cirrhosis in this patient were her mildly abnormal LFTs

What are the functions of the liver?

•Key role in intermediary metabolisme.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 childhoodand 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 testsViral Hepatitis Screen – A, B, C etc.

Autoimmune Heaptitis 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

UDPGlucoronosyltransferase

Hyperbilirubinaemia

•Jaundice evident with Bilirubin levels 35-70μmol/L•Normally 95% of plasma bilirubin is unconjugated

Unconjugated - prehepatic*(No bilirubinuria)

•Haemolyis•Resolving haematoma•Gilbert’s Syndrome•Crigler-Najjar syndrome

Conjugated – Hepatic/posthepatic(Bilirubinuria)

•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 associatedwith 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, Hyerlipidaemia•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 serologyAI hepatitis screenFe/TIBC/Ferritin/HFE genotypingCaeuruloplasmin if < 40 yrA1ATCoeliac screen

Ultrasound scanMRI/CTBx

? Muscleproblem

Causes of a Cholestatic Pattern of LFTs

Elevated ALP and GGT ± Bilirubin, relative to transaminases

Intrahepatic(Bilirubin not elevated)

•Medications•TPN•Sepsis•Postoperative•PBC•Alcoholic hepatitis•Liver mets•Pregnancy-related•CCF

Extrahepatic(Bilirubin elevated)

•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

What is GGT?Normal

?bone, placenta,Intestine etc.

Elevated

US/CT/MRI

Biliary dilation Focal mass No abnormality

Medications PBC -AMA

Consider other causes

Specialised investigations

Other LFTs

Serum ammonia -used for investigation of hepatic encephalopathy-lacks sensitivity and specificity-useful for 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 35-50 g/L

Bilirubin <17 umol/L

ALP* 40-120 IU/L*

AST 7-40 IU/L

ALT 7-35 IU/L

GGT 10-55 IU/L

* NB: Reference Range is age related

24 yr old male

Insurance medical showed abnormal LFTs ? Cause

Albumin 42 (35-50 g/L)

Bilirubin 38 (<17 umol/L)

ALP 98 (40-120 IU/L)

AST 30 (7-40 IU/L)

ALT 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 1

35 yr old female with a 4/52 hx of-malaise, anorexia, upr abdominal pain, ?haematuria-O/E Icteric

Alb 35

Bilirubin 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 thisimpact on her “haematuria”?

Case 2

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 “still growing”

Alb 46

Bilirubin 12

ALP 220 (40-120)

AST 20

ALT 20

GGT 9

What is the likely cause for the elevated ALP?

Which isoenzyme is increased?

Case 3

48yr old female is attending a lipid-clinic -polygenic hypercholesterolaemia-On atorvastatin 20mg/d for 2 years-C/o tired fatigue, malaise

Alb 42

TBilirubin 8

ALP 250 (40-120)

AST 38

ALT 26

GGT 220

LFTs measured 6/12 previously were normal

What further investigations would you perform?

What is the differential diagnosis?

Case 4

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 6.8 mmol/L

Alb 38

TBili 15

ALP 82

AST 58

ALT 72

GGT 67 (<55)

What further investigations would you suggest and why?

Case 5

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

28/4 3/5

Alb (35-50) 39 39

Tbili (3-17) 10 6

AST (7-40) 113 106

ALT (7-35) 95

Alk Phos (40-120) 352 372

GGT (5-40) 874 930

LDH (230-450) 426 495

CK (34-170) 82

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 CirrhosisIneffective erythropoiesis – sideroblastic anaemia, ThalassaemiaMultiple transfusionsBantu siderosisPorphyria 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 – DiabetesHeart – dilated cardiomyopathyJoints – arthropathyPituitary – secondary hypogonadism (males > females0Testses – primary hypogonadism (rarer)Parathyroid - hypocalceamia

Diagnosis of HH

•Increased Transferrin Saturation (Plasma Fe/TIBC)

55% - genotype45-55% - may consider genotype

•Increased Ferritin

•HFE genotype

•Liver Biopsy

•Liver Iron content

Figure A

C282Y H63D

1 2 3 1 2 3

1. Homozygous mutant

2. Heterozygous

3. Wild type (normal)

1. Homozygous mutant

2. Heterozygous

3. Wild type (normal)

Case Example : Haemochromatosis51yr old male

Total protein 71

Total Bilirubin 14

Alk Phos 82

GGT 39

AST 44

ALT 92

Serum Fe 38

TIBC 41

Transferrin sat 93%

Ferritin 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 caeruloplasminIncreased Urinary Cu excretion (Penicillamine Challenge Test)Liver Bx – measure Cu content