Biochemistry Flashcards
What do U&E measure:
Electrolytes (Potassium and Sodium) Renal function (Urea and Creatinine)
Hyponatraemia Sodium level
Less than 135mmol/L
What is important to look at for hyponatraemia
Osmalality: this is lower in true hyponatraemia
Volume status
Causes of hypovolaemia hyponatraemia
Vomiting, Diarrhoea
Renal: Diuretics (K sparing), Nephropathy (PKD, NAIDs, pyelonephritis), Adrenal insufficiency/Addison’s
Causes of isovolaemic hyponatraemia
SIADH (high urine osmolality assoc)
Drugs
Renal failure / AKI
Hyperthyroidism
Causes of hypervolaemic hyponatraemia
Liver failure
Congestive heart failure (fluid overload)
Renal failure / AKI
Nephrotic syndrome
Causes of hypernatraemia
Diabetes insipidus (Polydispsia and polyuria causes fluid and salt loss)
Poor water intake (e.g. elderly, bed bound)
Too much IV sodium
Hypokalaemia level
Potassium less than 3.5
Causes of hypokalaemia
Drugs: Diuretic (e.g Thiazides - Indapamide), Tx DKA
GI: D&V, high stoma output
Renal: renal tubular acidosis or drug induced renal damage
Endocrine: Metabolic acidosis
Causes of hyperkalaemia
K over 6.5 - this is a medical emergency needing an ECG monitoring and Tx
if less than 6.5 then Tx needed if ECG is abnormal
Renal failure / AKI (And also missing dialysis appt)
Drugs: K sparing (Spironolactone), Potassium supps
Rhabdomyolysis, DKA
ECG changes in hypokalaemia
Flat broad T-waves
ST-depression
Long QT
Ventricular dysrhythmia
ECG changes in hyperkalaemia
Tall-tented T-waves (moving to Sine-wave - this is very severe stage)
Loss of P
QRS broadening
Cardiac arrest rhythms
What needs to be looked at for creatinine
What takes this into account
Age, sex and muscle bulk.
An old thin lady with normal range creatinine may be in renal failures this is high for her.
eGFR
Ways of predicting GFR
eGFR
Creatinine clearance
What does osmolarity take into account
U&Es
Blood Glucose
What factors determine nutritional profile
Magnesium
Calcium
Phosphate
Albumin
Refeeding syndrome
Insulin release causes increased glycogen, fat and protein synthesis.
This requires magnesium, phosphate and potassium which are already depleted
Urine in Pre-renal AKI (hypoperfusion) Vs Renal AKI from ATN
In pre-renal the urinary sodium is low as Juxtaglomerular apparatus is function and can activate RAAS
In Renal AKI from ATN urinary sodium is high due to breakdown in physiological mechanisms
Similarly in pre-renal uraemia, Urine will be more concentrated than in ATN
Ways of predicting GFR
eGFR
Creatinine clearance
What does osmolarity take into account
U&Es
Blood Glucose
What factors determine nutritional profile
Magnesium
Calcium
Phosphate
Albumin
Refeeding syndrome
Insulin release causes increased glycogen, fat and protein synthesis.
This requires magnesium, phosphate and potassium which are already depleted
Urine in Pre-renal AKI (hypoperfusion) Vs Renal AKI from ATN
In pre-renal the urinary sodium is low as Juxtaglomerular apparatus is function and can activate RAAS
In Renal AKI from ATN urinary sodium is high due to breakdown in physiological mechanisms
What needs to be looked at for creatinine
What takes this into account
Age, sex and muscle bulk.
An old thin lady with normal range creatinine may be in renal failures this is high for her.
eGFR
Ways of predicting GFR
eGFR
Creatinine clearance
What does osmolarity take into account
U&Es
Blood Glucose
What factors determine nutritional profile
Magnesium
Calcium
Phosphate
Albumin
Refeeding syndrome
Insulin release causes increased glycogen, fat and protein synthesis.
This requires magnesium, phosphate and potassium which are already depleted
Urine in Pre-renal AKI (hypoperfusion) Vs Renal AKI from ATN
In pre-renal the urinary sodium is low as Juxtaglomerular apparatus is function and can activate RAAS
In Renal AKI from ATN urinary sodium is high due to breakdown in physiological mechanisms
Components of Bone Profile
Calcium
Phosphate
Alk Phosphatase
Albumin
(Other factors: PTH, Vit D)
PTH actions
(released due to low calcium)
Increased Calcium reabsorption from bone
Increased renal calcium reabsorption
Increased renal excretion of phosphate
Inc absorption of Ca from gut (Vit D mediated)
Osteoporosis
Calcium
Phosphate
ALP
Calcium Normal
Phosphate Normal
ALP Normal
Osteomalacia
Calcium
Phosphate
ALP
Calcium Reduced
Phosphate Reduced
ALP Increased
Pagets
Calcium
Phosphate
ALP
Calcium Normal
Phosphate Normal
ALP Increased
Mets
Calcium
Phosphate
ALP
Calcium Increased
Phosphate Increased
ALP Increased
Primary hyperPTH (from PTH overactivity)
Calcium
Phosphate
ALP
Calcium Increased
Phosphate Decreased
ALP Increased
Secondary hyperPTH (due to vitamin D def)
Calcium
Phosphate
ALP
Calcium Low
Phosphate Increased
ALP Increased
Tertiary hyperPTH (due to renal failure)
Calcium
Phosphate
ALP
Calcium Increased
Phosphate Decreased
ALP increased
Differentiated from Primary with Hx of renal impairment
Causes of hypercalcaemia
Bone mets
Multiple Myeloma
Hyperparathyroidism
Excessive Vit D
Seven Factors to test in LFTs
Bilirubin AST (not liver specific - muscle damage) ALT ALP (not liver specific - bone turnover) GGT Albumin PT
Autoimmune hepatitis test and result
Autoanitbody screen
ANA
Anti-smooth muscle
Anti-microsomal
PBC test
Anti-mitochondrial antibody
Coeliac test
Anti-Tissue Transglutaminase
Haaemochromatosis biochem
High Iron, ferritin and transferrin saturation
Low TIBC
Wilson’s disease biochem
Low Caeruloplasmin and elevated 24 hour urine copper conc
HCC biomarker
Alpha-Fetoprotein
Hepatocellular pattern of LFT dysfunction
Transaminitis (AST and ALT raised)
Obstructive pattern of LFT dysfunction
Elevated ALP and GGT
Bilirubin also high
(in severe cases AST and ALT may also rise due to back pressure in liver although not as much as ALP and GGT)
Causes og hepatocellular damage
Viral hepatitis Autoimmune hepatitis Drugs and toxins Alcohol Metabolic (Haemochromatosis, Wilson) NAFLD Malignancy (primary and mets) Congestive cardiac failure
Tumour markers: Colorectal
Carcinoembryonic antigen
Albumin and inflammation
Albumin is negative acute phase protein as it goes down in inflammation
What is CRP
Produced in Liver
Acute phase protein: high in infection and inflammation
When is ESR high and CRP normal
SLE
Multiple Myeloma
Uric acid metabolism
Produced during metabolism of purines and excreted by kidneys
Causes of high urate
Increased consumption of purines
Impaired uric acid excretion
(this is what causes gout - acute mono arthritis)
Tumour markers: HCC
Alpha-Fetoprotein
Tumour markers: Testicular teratoma, seminoma, choriocarcinoma
Human chorionic gonadotropin
Tumour markers: Prostate ca
PSA
Tumour markers: Ovarian
Ca-125
Tumour markers: Pancreatic Ca
Ca-19-9
Tumour markers: Colorectal
Carcinoembryonic antigen
Cause, Symptoms & Test for Cystic Fibrosis
Mutation in the gene for Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) responsible for Chloride transport across epithelial cells
Causes viscous secretions in lungs and pancreas and also infertility
Sweat test (Over 60mmol/L Chloride)
Fluid balance: E.g. of fluid entering the body
Food and drink
IV
Enteral or parenteral nutrition
Blood products
Fluid balance: E.g. of fluid leaving the body
Urine Bowel motions Blood loss Fluid from drains e.g. chest drain Insensible losses (expired and sweat) - 500ml/day (higher in burns, fever etc)
