Electrolyte Abnormalities Flashcards
What is the definition of hyponatremia?
Sodium <135
What are the symptoms and signs of hyponatremia?
Symptoms - none, headache, lethargy, nausea, vomiting, muscle cramps
Signs - disorientation, seizures, coma, death
What are the categories of causes of hyponatremia?
- Pseudohyponatremia
- Sodium depletion
- Excess water intake
- Reduced renal free water clearance
What causes pseudohyponatremia?
- Hyperglycaemia
- Hypertriglycerdiaemia
- Non-physiological osmolyte
If you correct these, the hyponatremia will correct itself
What causes sodium depletion?
Renal loss - diuretics, salt wasting, nephropathy
Extra renal loss - gut loss (vomiting)
What causes excess water intake?
- Diabetes insipidus
- IV therapy
What causes reduced renal free water clearance?
- Hypovolaemia
- Cardiac failure
- Nephrotic syndrome
- Hypothyroidism
- Hypoadrenalism
- SIADH
How should hyponatremia be managed?
- Fluid restriction
- Sodium replacement with hypertonic saline at a rate of 10mmol/L/24h
RISK OF CEREBRAL OEDEMA AND OSMOTIC DEMYELINATION SYNDROME DEATH IF THIS ISNT DONE WELL
What is hypernatremia?
Sodium > 144mmol/L
What are the signs and symptoms of hypernatremia?
Signs - Twitching, spasms, coma, death
Symptoms - THIRST, nausea, loss of appetite, confusion, weakness
What are the causes of hypernatremia?
- Dehydration (elderly, terminal ilness)
- Excess sodium in IV therapy
What is hypokalemia?
Potassium < 3.5
What are the signs and symptoms of hypokalemia?
Signs - ARRHYTHMIAS, paralysis
Symptoms - ASYMPTOMATIC, nausea, fatigue, weakness, constipation, cramping, palpitations
What are the complications of hypokalemia?
Cardio -arrhythmias
Neuromuscular - tetany, paralysis, rhabdomyolysis
Renal - decreased GFR, nephritis, metabolic alkalosis
Endocrine - growth retardation, decreased insulin secretion
What is hyperkalaemia?
Potassium < 5.0
What are the signs and symptoms of hyperkalemia?
SIGNS - ARRHYTHMIAS, paralysis
SYMPTOMS - weakness, parasthesia, paralysis
What are the complications of hyperkalemia?
Cardio - arrhythmias
Neuromuscular - parasthesia, weakness
Renal - decreased renal NH4 production
Endocrine - increased insulin secretion
What are the ECG features of hypokalemia?
- ST depression
- T wave flattening and inversion
- Prominent U waves
What are the ECG features of hyperkalemia?
- Tented T waves
What causes hypokalemia?
GI - deficiecnt intake, GI losses
Renal - metabolic alkalosis, diuretics, tubular disorders, magnesium depletion
Cell shifts without depletion
How is hypokalemia managed?
Oral replacement with Sando K tablets if mild/moderate
IV Kcl with 0.9% saline if severe
What causes hyperkalemia?
Decreased excretion - drugs, renal failure, addison, acidosis
Increased release from cells - acidosis, tissue damage (rhabdomyolysis), digoxin
Increased extraneous load - potassium chloride, salt substitutes, blood transfusion
How is hyperkalemia managed?
- Stabilise myocardium with calcium gluconate
- IV insulin and dextrose
- Salbutamol nebulisers
- Dialysis if no response
DO ECG!!!!
