Lecture 18 - Biochemical Tests Flashcards
Normal Na+ range
136-146 mmol/L
Normal K+ Range
3.5-4.6 mmol/L
Normal Cl- range
100-110 mmol. L
Normal HCO3- range
24-30 mmol/ L
Low Na+ risk
Confusion
Seizures,
Coma, death
Syndrome of inappropriate ADH
- elevated serum levels of ADH
- plasma osmolality low
- water retention
- increased ECF volume without edema
- concentrated urine
Origins of elevated ADH
- ectopic releae from lung
- enhance posterior pituitary release
Other causes of low Na+
- diuretics
- MDMA
- Addison’s disease
Treatment options for hyponatremia
- treat cause
- water restriction, urea, demeclocycline, vaptans
Risk for high Na+
- confusion
- seizures
- coma
- death
Diabetes insipidus: High Na+
1) cranial diabetes insipidus: serum ADH low, pituitary tumour, surgery, CNS infections
2) NEphrogenic diabetes insipidus: target organ resistance, Serum ADH high
Low K+ risk
- arrythmias
- digoxin toxicity
Clinical contexts of low K+
- diurectics
- GI K+ losses (diarrhea, vomiting)
- excessive mineralocorticoid effects
High K+ risk
- arrythmias
- asystole due to depolarization
Clinical contexts of high K+
- inadequate renal excretion
- addison’s disease (failure of adrenal cortex)
- Metabolic acidosis: K+ leaves cells
- Serious tissue injury
PRimary defect in CO2 levels
- elevated CO2: Respiratory acidosis: H+ rises
- decrease CO2: respiratory alkalosis: H+ falls
If primary defect is in H+
- high H+ : Metabolic acidosis: HCO3- falls
- low H+ : Metabolic alkalosis: HCO3- rises
If primary defect is in HCO3-
- decrease HCO3-: Metabolic acidosis
- increased HCO3- : metabolic alkalosis
High bicarbonate: metabolic alkalosis
- arterial pH >7.50
- causes; GI acid loss or high level of antacid intake
High bicarbonate: chronic respiratoru acidosis: renal comepnsation
- arterial pH
Low bicarbonate: metabolic acidosis
- primary abnormality and or excess tissue H+ production
Causes: normal chloride (diabetic ketoacidosis or lactic acidosis) or high chloride (intestinal bicarbonate loss or chronic renal failure)
Low bicarbonate: chronic respiratory alkalosis - renal compensation causes
- hyperventilation
- hypoxia
- fever
- salicylate toxicity
Glucose nromal range
- 3.8 - 6.1 mM
Low glucose dangers
- loss of consciousness, seizures, brain damage, death
Low glucose causes
- drug induced (diabetics on insulin)
- liver failure
- insulinoma
High glucose: chronically elevated in both type 1 and type 2 diabetics
- accelerated diabetic complications
- prolonged hyperglycemia
High glucose in type 1 diabetic
- risk of diabetic ketoacidosis
High gluose in type 2 diabetic
- risk of serious dehydration
- risk of hyperosmolar coma
Creatinine normal range
- 60 - 120 um
- monitor kidney function
High creatinine
Dehydration
- renal failure: acute or chronic
Urea normal range
- 3-8mmol/L
High urea causes
- enhanced protien breakdown
- renal failure
Calcium normal range
2.2-2.6 mM
Three main forms of calcium
- bound to albumin (45%)
- complexed with organic anions (5%)
- ionized (50%)
Hyperventilation
- lowers CO2 and lowers H+ in blood
- acute increase in plasma pH
- negative charge on albumin increase
- albumin binds more calcium
- ionized calcium drops
- dizziness, perioral numbness, paresthesia, tetanic contractions
Liver failrue
- albumin synthesis drops
- plasma albumin drops
- total calcium drops
- ionized calcium unchanged
Hypocalcemia
- neuromuscular irritability
- tetany
- cardiac arrythmias
- laryngospasm
- convulsion
- death
Causes of hypocalcemia
- familial or sporadic hypocalcemia
- hypoparathyroidism or resistance to PTH
- chronic renal failure
- impaired vit D metabolism
- hungry bones
Hypercalcemia
- primary hyperparathyoidiusm
- malignancy
- familial
- Vit D intoxication
- granulomatous disease
Total protein normal range
60-80 g/l
Albumin normal range
40-50 g/L
Bilirubin normal range
0-18 um
- derived from breakdown of heme
- elevated bilirubin in enhanced hemolysis or impaired excretion
Aminotransferases: AST and ALT
- role in detoxifying aa
- elevated in hepatitis
Other enzymes for liver status: ALP, GGT
- ALP: metabolism of organic phosphates
- GGT: role in aa transport
- both are elevated in biliary stasis or bile duct obstruction
- GGT elevated with chronic high ethanol intake
