Clinical Biochemistry- Electrolyte Tests Flashcards
Value for severe hyponatremia
<120mmol/L
What is hyponatremia?
low serum Na
results in hypotonicity
What are the symptoms of hyponatremia?
NV, anorexia, altered mental status, confusion, seizures, coma
What are the causes of hypovolemic hyponatremia?
GI losses
Renal/Skin/Lung losses
diuretics
What are the causes of isovolemic hyponatremia?
Water intoxication
Renal failure
SIADH
What are the causes of hypervolemic hyponatremia?
CHF
Liver damage
Nephrosis
Value for severe hypernatremia
> 160mmol/L
What are the symptoms of hypernatremia?
Seizures, thirst, lethargy, coma, restlessness, irritability, ataxia, tremors
Value for severe hypokalemia
<2.5mmol/L
What are the causes of hypokalemia?
Decreased intake
Excessive renal loss
Intracellular shift
Excessive GI loss
Value for severe hyperkalemia
> 8mmol/L
What are the symptoms of hyperkalemia?
V-fib, bradycardia, hypotension, cardiac arrest, muscle weakness, paralysis
What are the causes of hyperkalemia?
Excessive intake
Impaired renal function
Redistribution to ECF
What is pseudohyperkalemia?
Appears as hyperkalemia on lab results but caused by hemolysed lab samples
IC K released and added to serum
Value for severe hypochloremia
<75mmol/L
What are the causes of hypochloremia?
Severe loss of gastric fluid
Metabolic alkalosis
Renal losses (due to loss of Na)
Indirect cause by drugs
Value for severe hyperchloremia
> 125mmol/L
What are the causes of hyperchloremia?
Rarely in isolation
Accompanied by Na and water retention
Mostly caused by metabolic acidosis
Value for severe hypomagnesemia
<0.5mmol/L
What are the causes of hypermagnesemia?
GI or renal losses
Associated with refractory hypocalcemia and hypokalemia (need to treat low Mg first)
What are the symptoms of hypomagnesemia?
Weakness, increased reflexes, heart arrythmia, CNS changes, confusion, tingling and numbness in extremities
Value for severe hypermagnesemia
> 1.5mmol/L
What are the symptoms of hypermagnesemia?
Bradycardia, heart block, mental confusion, decrease in tendon reflexes, weakness, respiratory depression, hypocalcemia
What are the causes of hypermagnesemia?
Significant renal dysfunction
Magnesium overload – ISMP alert
What causes an ISMP safety alert?
Large doses of Mg (usually for seizures)
Ca injection is antidote
Value for severe hypocalemia
<1mmol/L
What are the symptoms of hypocalcemia?
Numbness, myalgias, tingling to tetany, hyperreflexia, cardiac arrythmias, hypotension, seizures
What are the causes of hypocalcemia?
Disorders of VD metabolism or PTH
Value for severe hypercalcemia
> 3mmol/L
What are the symptoms of hypercalcemia?
GI symptoms, lethargy, confusion, acute renal failure, ECG changes
What are the causes of hypercalcemia?
Malignancies
Primary hyperparathyroidism
Drug
What should Ca levels be interpreted with?
K
Albumin (Ca= Ca+0.02*(40-Albumin))
Value for severe hypophosphatemia
<0.3mmol/L
What are the symptoms of hypophosphatemia?
Muscle weakness, rhabdomyolysis, hemolysis, platelet dysfunction, cardiac and respiratory failure, encephalopathy, seizures
What are the causes of hypophosphatemia?
Reduced intake
Intracellular shift
Increased excretion
Chronic alcohol ingestion, diabetic ketoacidosis
Value for severe hyperphosphatemia
> 2.4mmol/L
What are the symptoms of hyperphosphatemia?
Calcium phosphate deposition in soft tissue, osteomalacia
