Electrolyte Abnormalities Flashcards
Hypernatraemia symptoms
Lethargy, thirst, weakness, irritability, confusion, coma, seizures
Hypernatraemia signs
Dehydration
Hypernatraemia causes
Fluid loss without water replacement (diarrhoea, vomit, burns)
Diabetes insipidus
Osmotic diuresis
Primary aldosteronism
Iatrogenic
Hypernatraemia investigations
FBC - PCV
U&Es - Na, urea
LFTs - albumin
Raised serum Na
Raised PCV
Raised albumin
Raised urea
Hypernatraemia management
Water orally
Glucose 5% IV slowly
If hypovolaemic - 0.9% saline
Hyponatraemia signs and symptoms
Anorexia, nausea, malaise
Headache, irritability, confusion, weakness, decreased GCS, seizures
Hyponatraemia causes
Hypervolaemic - Heart failure, renal failure, liver failure, nephrotic syndrome
Euvolaemic - SIADH, primary polydipsia
Hypovolaemic - Dehydration, renal salt wasting syndromes, Addison’s disease
Hyponatraemia investigations
Bloods U&Es (inc. eGFR) Random glucose Cortisol Osmolality TSH
Urine
Sodium
Osmolality
Hyponatraemia management
Correct underlying cause
Asymptomatic - fluid restriction
Symptomatic - cautious rehydration with 0.9% saline. DO NOT go too quickly - central pontine myelinolysis may occur. Max rise in Na of 15mmol/L/day
Hyperkalaemia signs and symptoms
Fast, irregular heartbeat, chest pain, weakness, palpitations, light-headedness
Hyperkalaemia causes (6)
Renal failure, Addison’s disease, K+ sparing diuretics, massive blood transfusion, ace inhibitors
Hyperkalaemia treatment
Non-urgent (K <6mmol/L): treat underlying cause, review medications.
Urgent (evidence of myocardial hyperexcitability OR K >6.5mmol/L): emergency, insulin and dextrose infusion and IV calcium gluconate.
Insulin and dextrose drives carbohydrates into cells, which takes K+ with it —> reduces blood potassium
Calcium gluconate stabilises cardiac muscle cells and reduces risk of arrhythmias (cardioprotective, does NOT reduce K+)
Hyperkalaemia ECG signs
Tall, peaked T-waves
Flattening or absence of P waves
Broad QRS complex
Hypokalaemia signs and symptoms (8)
Muscle weakness, hypotonia, hyporeflexia, cramps, tetany, palpitations, light headedness, constipation
Hypokalaemia ECG
Small or inverted T waves
Prominent U waves
Long PR interval
Depressed ST segments
Hypokalaemia causes (6)
Diuretics, vomiting and diarrhoea, pyloric stenosis, Cushing syndrome, Conn’s syndrome, renal tubular failure
Hypokalaemia treatment
If mild (>2.5mmol/L and no symptoms): give oral K+ supplement e.g. Sando-K. Review medications.
If severe: give IV K+ cautiously
Hypercalcaemia signs and symptoms (4)
‘Bones, stones, groans and psychic moans’
Bones - weakness
Stones - renal stones, ectopic calcification
Groans - abdo pain, vomiting, constipation
Psychic moans - tiredness, weakness, confusion, depression
Hypercalcaemia ECG
Decreased QT interval
Hypercalcaemia causes (6)
Malignancy (bone metastasis) Primary hyperparathyroidism Sarcoidosis Vitamin D intoxication Thyrotoxicosis Lithium
Hypercalcaemia investigations (9)
Albumin (low/normal - malignancy)
PTH (high - hyperparathyroidism)
Urea (raised - dehydration)
ALP - malignancy
FBC, protein electrophoresis, CXR, isotope bone scan
Hypercalcaemia management
- Correct dehydration (0.9% saline)
2. Bisphosphonates
From where and when is parathyroid hormone secreted?
Four parathyroid glands
Triggered by decreased serum calcium, controlled by negative feedback loop
Actions of parathyroid hormone
Increase osteoclast activity which leads to Calcium and Phosphate being released from bones.
Increased calcium reabsorption in kidney
Decreased phosphate reabsorption in kidney
Increased renal production of 1, 25-dihydroxy-vitamin D3
