Enzymes & Cardiac Markers

Question 1

Where is ALP found

Answer 1

Liver (esp. in bile ducts) Bone

Intestines Placenta

Question 2

Cause of raised ALP

Answer 2

• Pregnancy – 3rd trimester (from placenta)
o Bone – Paget’s disease, osteomalacia
o Liver – cholestasis, cirrhosis

Question 3

What should you measure for acute and chronic pancreatitis

Answer 3

o Chronic pancreatitis  measure faecal elastase

Acute- amylase

Question 4

What enzyme can you measure in IBD

Answer 4

Measure faecal calprotectin

Question 5

What is creatinine kinase a marker of

Answer 5

Muscle damage
 CK-MM = skeletal muscles (responsible for almost the entire normal plasma activity)
 CK-MB = cardiac muscle
 CK-BB = brain (activity is minimal even in severe brain damage)

Question 6

A 64-year-old man who smokes and has a family history of cardiovascular disease has recently been started on atorvastatin. Three weeks after commencing the tablet, he complains of generalised muscle pain. What is the working clinical diagnosis?

Answer 6

Statin-related myopathy
• CK-MM can help make the diagnosis (>x10 UL)
 Clinical syndromes of statin-related myopathy = myalgia  rhabdomyolysis (mostly, w/ simvastatin when co-prescribed other medications involved in CYP3A4 – i.e. clarithromycin)

Question 7

Myocardium enzymes and where they’re found

Answer 7

o Myoglobin = cytosolic enzyme (rise quickly)

o CK-MB = sub-cellular (mitochondria and nuclei)

Question 8

When should troponin be measured

Answer 8

o Rise at 4-6 hours post MI
o Peaks at 12-24 hours
o Remains elevated for 3-10 days

o Therefore, it should be measured at 6 hours and again at 12 hours after the onset of chest pain

Question 9

Cardiac failure markers

Answer 9

o Atrial NP (secreted by atria)
o Brain NP (secreted by ventricles)  used for:
 Assess ventricular function
 To exclude heart failure in a clinical setting (highly sensitive)