Clinical Biochemistry Flashcards
What does myalgia refer to?
- my = muscle
- algia = pain
- pain attributed to muscle
Myalgia is pain attributed to muscle. Creatine kinase (CK) is an enzyme that’s found in your skeletal muscle, heart muscle and brain. When any of these tissues are damaged, they leak creatine kinase into your bloodstream. In Myalgia, is CK always elevated?
- can be, but not always
What does myotonia relate to?
- myo = muscle
- tonia = muscle contraction
- inability of muscle to relax after contraction
What does myositis relate to?
- myo = muscle
- sitis = inflammation
- Inflammation of the muscle, often autoimmune
What does rhabdomyolysis relate to?
- rhabdo = rod like
- myo = muscle
- lysis = breakdown
- widespread breakdown of muscle fibres with raised CK
What does myopathy relate to?
- myo = muscle
- pathy = disease/pathophysiology
- General term to describe any disorder of muscles
What does dystrophy relate to?
- progressive loss of muscle mass and function
What is the most commonly used and sensitive marker for muscle disease?
1 - Creatine Kinase (CK)
2 - Lactate Dehydrogenase (LDH)
3 - myoglobin
4 - Troponin
1 - Creatine Kinase (CK)
Muscle diseases can be categorised into the following categories:
- Non-metabolic, genetically determined myopathies
- Metabolic myopathies
- Trauma
- Infection
- Inflammatory
What are non-metabolic, genetically determined myopathies?
1 - genetically based myopathies
2 - disease of the muscles associated with metabolism
3 - damage to muscle caused by external agents
4 - autoimmune conditions generally
1 - genetically based myopathies
- for example, duchenne’s syndrome, myotonic dystrophy
Muscle diseases can be categorised into the following categories:
- Non-metabolic, genetically determined myopathies
- Metabolic myopathies
- Trauma
- Infection
- Inflammatory
What are metabolic myopathies?
1 - genetically based myopathies
2 - disease of the muscles associated with metabolism
3 - damage to muscle caused by external agents
4 - autoimmune conditions generally
- disease of the muscles associated with metabolism
- hyperthyroidism, hyperparathyroidism for example
Muscle diseases can be categorised into the following categories:
- Non-metabolic, genetically determined myopathies
- Metabolic myopathies
- Trauma
- Infection
- Inflammatory
What are trauma myopathies?
1 - genetically based myopathies
2 - disease of the muscles associated with metabolism
3 - damage to muscle caused by external agents
4 - autoimmune conditions generally
3 - damage to muscle caused by external agents
- crush, ischaemic, steroids, statins for example
Muscle diseases can be categorised into the following categories:
- Non-metabolic, genetically determined myopathies
- Metabolic myopathies
- Trauma
- Infection
- Inflammatory
What are infection myopathies?
1 - damaged to muscle caused by infections
2 - disease of the muscles associated with metabolism
3 - damage to muscle caused by external agents
4 - autoimmune conditions generally
1 - damaged to muscle caused by infections
- generally bacterial or viral
Muscle diseases can be categorised into the following categories:
- Non-metabolic, genetically determined myopathies
- Metabolic myopathies
- Trauma
- Infection
- Inflammatory
What are inflammatory myopathies?
1 - genetically based myopathies
2 - disease of the muscles associated with metabolism
3 - damage to muscle caused by external agents
4 - autoimmune conditions generally
4 - autoimmune conditions generally
- dermatomyositis/polymyositis, sarcoidosis for example
What is the reference range for creatine kinase for a male aged >18 y/o?
1 - >250
2 - 100 - 200
3 - 10 - 200
4 - 40 - 320
4 - 40 - 320
What is the reference range for creatine kinase for a female aged >18 y/o?
1 - >250
2 - 100 - 200
3 - 25 - 200
4 - 40 - 320
3 - 25 - 200
A creatine kinase level that is 10 times above the upper normal level is commonly observed with what?
1 - polymyositis, rhabdomyolysis, Duchenne and myocardial infarction
2 - polymyositis, trauma, Duchenne and myocardial infarction
3 - polymyositis, nutritional deficit, Duchenne and myocardial infarction
4 - polymyositis, rhabdomyolysis, inflammatory and myocardial infarction
1 - polymyositis, rhabdomyolysis, Duchenne and myocardial infarction
- all are serious events or chronic
A creatine kinase level that is 5-10 times above the upper normal level is commonly observed with what?
1 - polymyositis, rhabdomyolysis, Duchenne and myocardial infarction
2 - polymyositis, rhabdomyolysis, Duchenne and myocardial infarction
3 - polymyositis, trauma, Duchenne and extreme exercise
4 - post-surgery, trauma, extreme exercise, Duchenne and myositis
4 - post-surgery, trauma, extreme exercise, Duchenne and myositis
A creatine kinase level that is 5 times above the upper normal level is commonly observed with what?
1 - body builders, athletes, hyperthyroidism and myocardial infarction
2 - statins, body builders, Duchenne and myocardial infarction
3 - body builders, athletes, hyperthyroidism and statins
4 - post-surgery, trauma, extreme exercise, Duchenne and myositis
3 - body builders, athletes, hyperthyroidism and statins
Rhabdomyolysis is the rapid destruction of striated skeletal muscle. In addition to creatine kinase what other key marker, specific to skeletal muscle is released into the blood?
1 - aspartate aminotransferase
2 - myoglobin
3 - hemoglobin
4 - lactate dehydrogenase
2 - myoglobin
- only contained with skeletal muscle
What are some of the most common causes of rhabdomyolysis?
- severe exercise
- injury (trauma, electrocution, crush injuries, surgery)
- ischaemia
- metabolic (severe hypokalaemia or hypophosphataemia, malignant hyperpyrexia, McArdle disease, phosphofructokinase deficiency
- infections, toxins, drugs
Rhabdomyolysis is the rapid destruction of striated skeletal muscle. How can we test to see if a patient has rhabdomyolysis in the blood, which generally results in creatine kinase levels that are 10 times above the upper limit of normal?
- CK >10 x ULN
- hyperkalaemia (released from muscle)
- hyperuricaemia (from purines, nephrotoxic)
- hyperphosphataemia
- jypocalcaemia
- rise in [creatinine]>[urea]
- metabolic acidosis (release of lactate and other acids)
Rhabdomyolysis is the rapid destruction of striated skeletal muscle. How can we test to see if a patient has rhabdomyolysis in the urine?
- urine may appear red/brown, BUT no urine for first 12 hours, then after this it will be red/brown
- peroxidase increased
What effect can rhabdomyolysis, which causes high levels of myoglobin have on the kidneys?
1 - hypovolaemia (low extracellular fluid)
2 - metabolic acidosis
3 - aciduria
4 - hyperuricaemia
What are 2 key risk factors for rhabdomyolysis?
1 - gender and obesity
2 - gender and high creatine kinase levels
3 - age and gender
4 - age and high creatine kinase levels
4 - age and high creatine kinase levels
Compartment syndrome occurs when the pressure within a compartment increases, restricting the blood flow to the area and potentially damaging the muscles and nearby nerves. How can compartment syndrome cause rhabdomyolysis?
- pressure in a compartment rises above blood pressure
- muscles becomes ischemic and then necrotic
- rhabdomyolysis follows causing myoglobinemia.
In addition to biochemical blood measures, what other 4 tests can we use to look at muscle?
1 - histology
2 - EMG
3 - genetics screening
4 - Immunocytochemical
What does MELAS stand for?
- mitochondrial encephalomyopathy, lactic acid and stroke like episodes
- a common mitochondrial disease
Bone formation, also called osteogenesis is the formation of new bone. What are the 2 key markers of bone formation?
1 - P1NP and creatine kinase
2 - PN1P and Alkaline Phosphatase
3 - Alkaline Phosphatase and Cathepsin K
4 - Alkaline Phosphatase and Hydroxyproline
P1NP = Procollagen 1 amino-terminal extension peptide
2 - PN1P and Alkaline Phosphatase
- PN1P is the key assay used
- ALP
Bone formation, also called osteogenesis is the formation of new bone. The 2 key markers of bone formation are PN1P and Alkaline Phosphatase (ALP). Why is ALP a useful marker of bone formation?
1 - low in presence of RANK-L
2 - release by osteoblasts for osteoid formation
3 - accentuates osteoblast activity
4 - initiates osteoblast activity
P1NP = Procollagen 1 amino-terminal extension peptide
2 - released by osteoblasts for osteoid formation
- ALP removes phosphate from phosphate so phosphate can diffuse into bone with Ca2+
- phosphate and Ca2+ are required for mineralisation of osteoid seam
Bone formation, also called osteogenesis is the formation of new bone. The 2 key markers of bone formation are PN1P and Alkaline Phosphatase (ALP). Why is PN1P a useful marker of bone formation?
1 - synthesised by osteoblasts for collagen fibril deposition
2 - synthesised by osteoclasts for collagen fibril deposition
3 - synthesised by osteocytes for collagen fibril deposition
4 - synthesised by monocytes for collagen fibril deposition
P1NP = Procollagen 1 amino-terminal extension peptide
1 - synthesised by osteoblasts for collagen fibril deposition
- N and C terminals are cleaved from PNP1
- PNP1 is then used to deposit collagen fibril in the osteoid tissue
The 2 key markers of bone formation, also called osteogenesis are Procollagen 1 amino-terminal extension peptide (PN1P) and Alkaline Phosphatase. What is PN1P in bone formation?
1 - marker of osteoclasts
2 - an enzyme involved in the synthesis of collagen
3 - a protein signalling molecule
4 - a peptide formed during type 1 collagen synthesis
4 - a peptide formed during type 1 collagen synthesis
- 90% of bone is collagen
The 2 key markers of bone formation, also called osteogenesis are Procollagen 1 amino-terminal extension peptide (PN1P) and Alkaline Phosphatase. What is ALP in bones?
- ALP hydrolyses inorganic pyrophosphate which is a naturally occurring inhibitor of mineralization
- ALP also provides inorganic phosphate
- essentially helps mineralise collagen in bones
The 2 key markers of bone formation, also called osteogenesis are procollagen 1 amino-terminal extension peptide and Alkaline Phosphatase. What other 2 markers are used clinically to assess bone formation?
1 - Osteocalcin and Procollagen 1 carboxy-terminal extension peptide (P1CP)
2 - Procollagen 1 carboxy-terminal extension peptide (P1CP) and Hydroxylysine
3 - Osteocalcin and Hydroxylysine
4 - Procollagen 1 carboxy-terminal extension peptide (P1CP) and Hydroxylysine
1 - Osteocalcin and Procollagen 1 carboxy-terminal extension peptide (P1CP)
N-telopeptide of collagen cross-link (NTX) and C-telopeptide of collagen cross-link (CTX) are the 2 ends of the protein collagen (N = start of a protein and C = end of a protein). These can both be measured via antibodies to assess bone health. Why are these important when looking at bone health?
- NTX and CTX is used to identify the breakdown of collagen
- higher levels demonstrate collagen (bone) is being reabsorbed by osteoclasts
What are the 2 prominent tests that are used to assess bone formation and bone reabsorption?
1 - CTX (bone reabsorption) and P1NP (bone formation)
2 - NTX (bone reabsorption) and P1NP (bone formation)
3 - CTX (bone reabsorption) and ALP (bone formation)
4 - NTX (bone reabsorption) and ALP (bone formation)
1 - CTX (bone reabsorption) and P1NP (bone formation)
When looking at gout, what should patients aim to get urate below?
1 - <100 umol/L
2 - <200 umol/L
3 - <300 umopl/L
4 - <400 umol/L
3 - <300 umopl/L
- >500 umopl/L is diagnostic of gout
Is gout more common in men or women?
- men
What are the medical terms used to describe vitamin D deficiency in adults and children?
- adults = osteomalacia
- children = rickets
What can vitamin D deficiency cause in bones?
- soft and brittle bones
- cause widening of growth plates and metaphysis
What are the 3 causes of osteomalacia?
- vit D deficiency - low intake plus inadequate sunlight exposure or malabsorption
- abnormal vit D metabolism: Liver and Renal disease; Drugs (anticonvulsants)
- low phosphate: intake, excess losses ; Vitamin D dependent rickets type I and II
How can osteomalacia present clinically?
- malaise (general feeling of discomfort/nausea)
- bone pain
- proximal muscle weakness / myopathy
Paget disease is a bone disease. What is paget disease?
- excessive bone reabsorption
- followed by excessive bone formation
- results in abnormal shaped bones and increased risk of fractures
Paget disease is a bone disease, characterised by excessive bone reabsorption followed by excessive bone formation. This can result in abnormal shaped bones and increased risk of fractures. How is this normally detected?
- on X-ray for something else
- excessively raised alkaline phosphate (ALP) as involved in mineralisation
Rheumatoid factor is an antibody that targets what part of antigens on proteins?
- Fc region
What is the most specific marker for RA?
- cyclic citrullinated protein (anti-CCP)
