Fluid and electrolyte imbalance

Question 1

What is the normal range for blood pH?

Answer 1

7.35–7.45

Question 2

What defines acidosis and alkalosis?

Answer 2

Acidosis: pH < 7.35

Alkalosis: pH > 7.45

Question 3

What are the two main types of acid-base disorders?

Answer 3

Metabolic (bicarbonate-related)

Respiratory (CO₂-related)

Question 4

What is metabolic acidosis?

Answer 4

A condition in which there is a decrease in blood bicarbonate (HCO₃⁻) or an increase in acid, resulting in pH < 7.35.

Question 5

What are common causes of metabolic acidosis?

Answer 5

Lactic acidosis

Diabetic ketoacidosis

Renal failure

Diarrhoea (bicarbonate loss)

Ingestion of toxins (methanol, ethylene glycol)

Question 6

How does the body compensate for metabolic acidosis?

Answer 6

By hyperventilating to reduce CO₂ (respiratory compensation).

Question 7

What is the role of sodium bicarbonate in metabolic acidosis?

Answer 7

It may be used in severe acidosis (e.g., pH < 7.1) to buffer excess acid, but use must be cautious and monitored.

Question 8

What is lactic acidosis?

Answer 8

A form of metabolic acidosis caused by the accumulation of lactic acid from anaerobic metabolism.

Question 9

What can cause lactic acidosis?

Answer 9

Shock

Hypoperfusion (sepsis, cardiac arrest)

Hypoxia

Metformin (especially in renal impairment)

Liver failure

Question 10

What is Hartmann’s solution and when is it used?

Answer 10

Hartmann’s (contains sodium lactate) is used perioperatively for fluid resuscitation but should be avoided in lactic acidosis.

Question 11

What is metabolic alkalosis?

Answer 11

A condition where there is excess bicarbonate or loss of hydrogen ions (H⁺), leading to pH > 7.45.

Question 12

Common causes of metabolic alkalosis?

Answer 12

Vomiting (loss of gastric acid)

Diuretic use (e.g., loop and thiazide)

Excess alkali ingestion

Hypokalaemia and chloride depletion

Question 13

What is the treatment for metabolic alkalosis?

Answer 13

Address the underlying cause

Replace potassium and chloride

May require acidifying agents in severe cases

Question 14

What is respiratory alkalosis and what causes it?

Answer 14

Caused by low CO₂ due to hyperventilation (e.g., anxiety, pain, altitude, fever)

Question 15

What is the immediate treatment for acute symptomatic hypocalcaemia (e.g., seizures, tetany)?

Answer 15

10 mL of 10% calcium gluconate (2.25 mmol) slow IV injection; repeat or follow with infusion of 40 mL (9 mmol) over 24 hours.

Question 16

How are mild hypocalcaemia cases usually managed?

Answer 16

Oral calcium supplements (e.g., calcium lactate or calcium gluconate), often with vitamin D.

Question 17

What are common treatments for hypercalcaemia?

Answer 17

Hydration with IV fluids, bisphosphonates, and treatment of the underlying cause.

Question 18

How is mild hypomagnesaemia typically treated?

Answer 18

Oral magnesium supplements such as magnesium aspartate.

Question 19

What is the treatment for severe or symptomatic hypomagnesaemia?

Answer 19

Intravenous magnesium with monitoring of serum levels and renal function.

Question 20

What measures are taken for mild hypermagnesaemia?

Answer 20

Discontinue magnesium medications, hydrate, and use loop diuretics like furosemide to enhance excretion.

Question 21

How is severe hypermagnesaemia treated?

Answer 21

IV calcium gluconate to counter cardiac effects and possibly dialysis if renal impairment exists.

Question 22

What is the main caution in treating severe hyponatraemia?

Answer 22

Correct sodium slowly (≤10 mmol/L per 24 hrs) to avoid osmotic demyelination syndrome.

Question 23

How is hypernatremia primarily managed?

Answer 23

Rehydration with dilute IV fluids.

Question 24

How is mild hypokalaemia (3.0–3.5 mmol/L) treated?

Answer 24

Increase dietary potassium or give oral potassium supplements if needed.

Question 25

What is important to monitor during intravenous potassium supplementation?

Answer 25

Cardiac monitoring to avoid arrhythmias.

Question 26

How does magnesium deficiency affect potassium levels?

Answer 26

Magnesium deficiency can worsen hypokalaemia; magnesium should be corrected first.

Question 27

What is the treatment for severe hypophosphataemia (<0.3 mmol/L)?

Answer 27

Intravenous phosphate with close monitoring of electrolytes every 6 hours.

Question 28

When are oral phosphate supplements used?

Answer 28

In mild hypophosphataemia or asymptomatic cases.

Question 29

What are common treatments for hyperphosphatemia?

Answer 29

Dietary phosphate restriction, phosphate binders, and dialysis if necessary.

Question 30

Who typically needs oral potassium replacement?

Answer 30

Patients on digoxin, anti-arrhythmics, with secondary hyperaldosteronism, chronic diarrhoea, elderly with poor diet, or long-term corticosteroid use.

Question 31

What is Oral Rehydration Therapy (ORT) used for?

Answer 31

Rehydration and electrolyte replacement in diarrhoea-related dehydration.

Question 32

What IV fluid is preferred for treating sodium depletion perioperatively to avoid acidosis?

Answer 32

Hartmann’s solution (compound sodium lactate).

Question 33

When is intravenous glucose used in electrolyte management?

Answer 33

To replace water, treat hypoglycaemia, provide energy, and in hyperkalaemia treatment with insulin.

Question 34

For what indication is intravenous sodium bicarbonate used?

Answer 34

Severe metabolic acidosis (pH <7.1).

Question 35

What are plasma substitutes like albumin used for?

Answer 35

To maintain circulatory volume in hypovolaemia or shock; albumin used post-acute phase for volume deficit.