Zusammenfassung der Ressource
3.26
Abnormalities of
sodium and
potassium
- Sodium 135-145
- Hypernatraemia
- Signs and symptoms
- Dehydrated, thirsty, weak and tired
- Irritable, confused, low GCS, fitting
- Causes
- not enough water
- low intake
- increased loss
- dermal - sweating, burns
- GI - D/V
- renal
- diuretics
- Diabetes insipidus - polyuria
- hyperaldosteronism
- osmotic diuresis e.g. DKA
- too much sodium - iatrogenic (saline)
- Management
- 1. Oral water 2. IV Dextrose (5%)
3. IV saline
- Hyponatraemia
- Signs and symptoms
- anorexia, nausea, malaise
- headaches, irritable, low GCS, fitting
- Causes
- dehydration
- urinary sodium >20mmol/L
- addisons
- diuretics
- osmotic e.g DKA
- polyuric renal failure
- low urinary sodium: D/V, burns, sweating...
- euvolaemia
- urine osmolality >500: SIADH. Rx = ADH antagonist e.g. domeclocycline
- low osmolality: primary polydipsia, glucocorticoid deficiency
- fluid overload
- Nephrotic syndrome
- Cardiac, liver or renal failure
- Management
- treat cause
- fluid restriction
- saline*
Anmerkungen:
- no more than 15mmol increase per day, due to risk of central pontine myelinosis
- Potassium 3.5-5
- Hyperkalaemia
- Signs and symptoms
- palpitations, chest pain, light headed
- weakness
- investigations
- ECG: Tall T waves and small P waves; VF
- Causes
- drugs e.g. K+ sparing diuretics
- endocrine e.g. addisons
- trauma e.g. rhabdomyolysis
- iatrogenic
- metabolic e.g. acidosis
- Management
- Acute
- 1. protect mycardium with IV calcium gluconate
- 2. push K+ into cells with IV insulin + dextrose; nebulised salbutamol;
- 3. Prevent absorption with calcium resonium
- 4. Remove K+ with dialysis
- Chronic: treat cause
- Hypokalaemia
- Signs and symptoms
- neurological signs resembling LMN lesion:
weakness, hypotonia, hyporeflexia, tetany
- palpitation and lightheadedness
- Causes
- Infection -> D/V
- Metabolic: alkalosis
- medication e.g. diuretics, steroids
- endocrine e.g. cushings, conns
- Management
- K+ replacement.
Anmerkungen:
- if giving IV, give no more than 20mmol/h, and no more than 40mmol/L