Clinical implications of electolyte disruption

Question 1

What are the effect of each ion electrolyte disruption?

Answer 1

Na- Hypo/hypernatremia
K- Hypo/hyperkalemia
HCO3-= Acidosis/ Alkalosis

Question 2

What is hyponatremia?

Answer 2

Decrease .in [Na+]o, serum < 135 mmol/L (normal 135-145 mmol/L)
Common electrolyte disorder Accounts for ~25% of acute hospital admissions

Question 3

What are the causes of hyponatremia?

Answer 3

• Renal disease (inadequate reabsorption of salts)
• Diuretics (including urine outputs, used to reduce total body water in cases of hypertension)
• Liver Cirrhosis (alcoholism)
• Congestive heart failure (water retention)

Question 4

How does hyponatremia affect electrical excitability?

Answer 4

Reduced extracellular Na conc= reduced excitability

Question 5

What are the symptoms of hyponatremia?

Answer 5

• Muscle cramps
• Weakness, fatigue
• Altered mental state= confusion, hallucinations, decreased consciousness, possible coma

Question 6

What is the main acute danger of hyponatremia?

Answer 6

Brain oedema- swelling of neurons and glia

Question 7

What is hypernatremia?

Answer 7

Inc. in [Na+]o, serum > 145 mmol/L (normal 135-145 mmol/L)
Much less common electrolyte disorder Accounts for ~1% of acute hospital admissions

Question 8

What are the causes of hypernatremia?

Answer 8

• Renal failure (chronic or acute= water loss and dehydration)
• Fever, diarrhoea, vomiting (water loss especially in elderly and infants)

Question 9

What are the symptoms of hypernatremia?

Answer 9

• Tremor
• Seizures and twitching
• Hyper-reflexia (exaggerated reflexes)
• Convulsions
• Intense thirst leading to lethargy, stupor and coma

Question 10

What is the main acute danger of hypernatremia?

Answer 10

Brain shrinkage (dehydration of neurons and glia) and bleeding through damage to blood vessels in the brain

Question 11

What is hypokalemia?

Answer 11

Dec. in [K+]o, serum < 3.5 mmol/L (normal 3.5-5.0 mmol/L) Most common electrolyte disorder

Question 12

What are the causes of hypokalemia?

Answer 12

• Renal disease (inadequate reabsorption of salts)
• Diuretics
• Liver cirrhosis (chronic alcoholism)
• Malnutrition/ malabsorption in GI tract

Question 13

How does hypokalemia affect electrical excitability?

Answer 13

Decreased extracellular K conc= K+ leaves cell during rest, more hyperpolarised and decreased excitability

Question 14

What are the symptoms of hypokalemia?

Answer 14

Mild- muscle weakness, fatigue, constipation, cardiac arrhythmias
Severe- Muscle paralysis, respiratory paralysis, paralysis of GI tract

Question 15

What is the main acute danger of hypokalemia?

Answer 15

Potentially fatal abnormal heart rhythms

Question 16

What is hyperkalemia?

Answer 16

Inc. in [K+]o, serum > 5.5 mmol/L (normal 3.5-5.0 mmol/L) Less common electrolyte disorder

Question 17

What are the causes of hyperkalemia?

Answer 17

Decreased kidney function/ drug interactions during the treatment of kidney infections- interferes with urinary excretion

Question 18

What are the symptoms of hyperkalemia?

Answer 18

• Impairment of neuromuscular, cardiac and GI organ systems

- Ventricular fibrillation

Question 19

How does hyperkalemia affect electrical excitability?

Answer 19

Increased extracellular conc= Decreased driving force so overall depolarisation

Question 20

What is the main acute danger of hyperkalemia?

Answer 20

Increased risk of cardiac arrest