Disturbances of potassium concentration (chemical pathology) Flashcards

1
Q

What roles do potassium do? (5)

A

-Hormonal secretion
-Maintenance of trans membrane potential.
-Regulation of acid base balance
-Cellular growth, protein synthesis.
-Contraction of muscle, CVS, CNS and respiratory function.

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2
Q

How do we obtain potassium balance (3)

A

•Na+/K+ (ATPase) transporter- Found in all cells and it throws 3Na+ out of the cell and 2K+ in.
•H+/K+ (ATPase) transporter- Found in the GIT and renal tubules, throws H+ out and K+ into the cell.
•Na+/K+/2Cl- (co transporter)- found in the loop of henle.

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3
Q

How does aldosterone stimulate potassium excretion? (2)

A

It stimulates it directly by increasing the active secretion of potassium in the distal tubule.
Indirectly by stimulating the active reabsorption of sodium in the distal tubule and collecting ducts.

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4
Q

Abnormalities in potassium balance occur as a result of what?

A

Depletion, excess or shift btwn compartments (ECF and ICF).

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5
Q

Acidosis leads to how much levels of potassium?

A

Hyperkalaemia (high levels)

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6
Q

Common cause of hypokalemia

A

Diuretic use

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7
Q

Other causes of hypokalaemia

A

-Diarrhoea
-Vomiting
-Mineralocorticoid excess
-Glococorticoid excess
-Metabolic alkalosis

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8
Q

Which potassium abnormality is a medical emergency?

A

Hyperkalaemia

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9
Q

What are the symptoms of hyperkalaemia? (3)

A

-Weakness, fatigue, shortness of breath.

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10
Q

ECG changes in hypokalaemia (3)

A

-T-wave flattening
-ST-segment changes
-Prolonged U-wave

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11
Q

ECG changes in hyperkalaemia (3)

A

-Peaked T-wave
-Prolonged PR segment
-Prolonged QRS complex

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12
Q

What are the causes of hyperkalaemia? (4)

A

-Pseudo hyperkalaemia (prolonged tourniquet during venepuncture, haemolysis)
-Excessive intake (Excessive IV, orally)
-Redistribution from ICF to ECF.
-Decreased excretion.

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