U + Es → NaCl + K

Question 1

What is hypernatraemia?

Answer 1

• Hypernatraemia is defined as a serum sodium concentration exceeding 145 mmol/L → too much salt in the blood.
• Hypernatremia is a “water problem,” not a problem of sodium homeostasis.

Question 2

What are the symptoms of hypernatraemia?

Answer 2

• Lethargy
• Thirst
• Irritability
• Confusion
• Fits
• Coma
• Signs of dehydration

Question 3

What is the treatment for hypernatraemia?

Answer 3

• Oral H20
• if not, Glucose
• 0.9% saline in hypovolaemia

Question 4

What are the causes associated with hypernatraemia?

Answer 4

Usually due to loss of H20 > NaCl :

• Fluid loss with no H20 replacement → Diarrhoea, burns, vomit.
• Diabetes insipidus → Large urine volume• Osmotic diuresis
• Primary aldosteronism• Iatrogenic → Excess saline given.

Question 5

What is HYPOnatraemia?

Answer 5

• Hyponatremia is an electrolyte abnormality that can be seen in isolation or, as most often is the case, as a complication of other medical illnesses.
• It is defined as a serum sodium Lvl <135

Question 6

What are the signs and symptoms of Hyponatraemia?

Answer 6

Initially:

• Anorexia, Nausea, Malaise.Followed by:
• Headache, Irritability, confusion, weakness, ↓GCS, and seizuresCardiac failure or oedema may help indicate cause.

Question 7

What are the causes of Hyponatraemia when the patient is dehydrated but urinary sodium is greater than 20mmol/l ?

Answer 7

In this scenario Na+ and H20 are lost via the kidneys:• Addisons disease

• Renal failure: diuretic phase of renal failure, Nephrocalcinosis or medullary cystic disease.
• Diuretic excess
• Osmolar diuresis

Question 8

What are the causes of Hyponatraemia when the patient is dehydrated but urinary sodium is less than 20mmol/l ?

Answer 8

Implies that Na+ and H20 are lost othere than via the kidney:

• Diarrhoea
• Vomiting
• Fistulae
• Burns
• Rectal villous adenoma
• Small bowel obstruction
• Trauma
• Cystic Fibrosis
• Heat exposure

Question 9

What are the causes of Hyponatraemia when the patient is not dehydrated and the patient is odematous?

Answer 9

• Nephrotic syndrome
• Cardiac failure
• Liver cirrhosis → Hyponatraemia may precede oedema
• Renal failure

Question 10

What are the causes of Hyponatraemia when the patient is not dehydrated but the patient is not oedematous?

Answer 10

• SIADH → Urine osmolality >100mmol/kg
• Water overload
• Severe hypothyroidism
• Glucocorticoid insufficiency

Question 11

What regulates plasma potassium lvls?

Answer 11

It is controlled by a number of different mechanisms including:

• aldosterone
• acid-base balance
• insulin levels

Question 12

Why is metabolic acidosis associated with hyperkalaemia?

Answer 12

Metabolic acidosis is associated with hyperkalaemia as hydrogen and potassium ions compete with each other for exchange with sodium ions across cell membranes and in the distal tubule

Question 13

What drugs cause hyperkalamia?

Answer 13

• potassium sparing diuretics
• ACE inhibitors
• angiotensin 2 receptor blockers
• spironolactone
• ciclosporin
• heparin → thought to be caused by inhibition of aldosterone secretion

Question 14

What foods are high in potassium?

Answer 14

• salt substitutes (i.e. Contain potassium rather than sodium)
• bananas, oranges, kiwi fruit, avocado, spinach, tomatoes

Question 15

What Pneumonia related organism can cause Hyponatraemia?

Answer 15

Legionella