Metabolic Flashcards
Give 5 signs or symptoms of hypocalcaemia
- Numbness/Tingling of mouth/lips
- Impaired orientation/confusion
- Anxiety
- Seizures
- Increased muscle tone
- Carpopedal spasms
- Skin abnormalities
What is Trosseau’s sign?
- Occurs in hypocalcaemia
- A blood pressure cuff is inflated above systolic BP and causes a carpopedal spasm
What is Chvostek’s sign?
- Tapping over the facial nerve causes twitching of facial muscles
What ECG changes are seen in hypocalcaemia?
- Prolonged QTc
- Sometimes AF or Torsades de Pointes
Give 4 main causes of hypocalcaemia
- vitamin D deficiency
- Hypoparathyroidism
- Rhabdomyolysis
- Mg deficiency (due to end organ PTH resistance)
How can you treat hypocalcaemia?
- calcium gluconate/calcium replacement 10ml of 10% for severe low calcium levels
- more milder give 5mmol/6hrs
What are some causes of hypernatraemia?
- diabetes insipidus
- excessive sodium infusion
- primary aldosteronism
What is the definition of hyponatraemia and what are 5 common causes?
Plasma sodium <130mmol/L
- Hypovolaemic - Addison’s, Fluid Loss (diarrhoea, dehydration), Drugs (PPI, SSRI, ramipril, diuretics, carbamazepine, tricylcics)
- Euvolaemic - SIADH
- Hypervolaemic - Nephrotic syndrome
How might a low sodium present?
- Confusion
- Headache
- Lethargy
- Weakness
- Abdominal pain
At what rate should sodium be corrected and why?
10-12mmol/kg/day
Too fast runs a risk of central pontine myolinosis (CPM). This is demyelination of the pons resulting in lethargy, confusion, paraparesis or a coma. There is a risk of cerebral oedema.
(Acute hypernatraemia can be corrected quicker without worrying about large fluid shifts)
What is SIADH?
Syndrome of Inappropriate ADH secretion. There is increased ADH released resulting in increased water retention by the collecting ducts, and increased sodium loss.
What can cause SIADH?
- SCC lung cancer that produces ADH
- Neurological disorder (stroke, CNS, SAH, meningitis)
- Infections
- Drugs (SSRI, sulfonylurea)
What would be seen in investigations for SIADH?
- Low sodium
- Low plasma osmolarity (increased water retention but electrolyte loss) therefore high urine osmolarity
- Urine - high sodium, high osmolarity
What drugs cause SIADH?
- SSRI
- Tricyclics
- Carbamazepine
- Vincristine
- Sulfonylureas
What are some causes of a high lactate?
- Infection (metabolic acidosis, sepsis)
- Dehydration
- Seizures
What are some causes of hyperkalaemia?
- Renal disease
- Increased K+ intake
- DKA
- Addison’s
What are some causes of hypokalaemia?
- Increased vomiting
- Diuretics
- Pyloric stenosis
- Addison’s Disease
- AKI
- Drugs - ACE-i, K+ sparing diurectics, ARB, heparin
- Rhabdomyolysis
What is considered moderate and severe hyperkalaemia?
Moderate - 6-6.4
Severe - >6.5
What are signs of hyperkalaemia?
- Weakness
- Fatigue
- SOB
- Muscular paralysis
- Palpitations
- Chest pain,
- Lightheadedness
What are you immediate management options when you are called to review a patient with a high potassium?
- ECG - check for arrythmias (broad QRS, reduced p-waves, peaked t-waves)
- Stop potassium intake, diuretics
- If ECG abnormal: calcium gluconate
- Insulin + Glucose (10% dextrose 250ml, 10 units immediate release insulin)
- If K+ remains high then consider salbutamol nebs, dialysis
What is your first line management of hypercalcaemia?
IV Fluids
THEN IV Pamindronate (bisphosphonate)
What is short synacthen used to diagnose?
Addison’s Disease
A synacthen test measures cortisol levels, then give synthetic ACTH and remeasure cortisol
Addison’s is a disease of adrenal insufficiency either primary (due to low ACTH) or secondary (cortisol deficiency).
Why is urine osmolality useful in hyponatraemia?
A high urine osmolality would indicate SIADH.
Give 5 common presenting features of hypercalcaemia?
- Dehydration
- Psychiatric manifestations
- Confusion
- Anorexia
- Constipation
- Bone pain
- Abdominal pain
- Renal stones (bones, moans, stones, abdominal groans)
