Hyperkalaemia

Question 1

Hyperkalaemia

Internal Balance shift

Insulin Deficiency

Answer 1

• After a meal glucose incrteases in the blood, insulin releases and stimulates uptake of glucose
• Insulin also increases Na/K pump, pulls K into cells
• Type 1 diabetics don’t make insulin therefore K sits in blood rather than being taken into cells giving hyperkalaemia

Question 2

Hyperkalaemia

Internal Balance shift

Acidosis

Answer 2

Higher conc of H ions which lowers the pH

To compensate H ions enter cell and K ions leave cell results in hyperkalaemia

In Respiratory acidosis K ions unaffected because CO₂ can move freely without an exchange pump therefore no hyperkalaemia

Question 3

Hyperkalaemia

Internal balance shift

Metabolic Acidosis

Answer 3

No hyperkalaemia as lactic acid and ketoacid can move freely into cell

Both beta blockers alpha adrenergic agonists cause hyperkalaemia

Question 4

Hyperkalaemia

Internal balance shift

Hyperosmolarity/Cell Lysis

Answer 4

Hyperosmolarity:

• Increased extracellular osmolarity relative to the intracellular space
• This gradient pulls water out of cells into the extrcellular space
• This causes K⁺ to go into extrcellular space

Cell Lysis:

• When a cell lysis it releases lots of K⁺
• Causing hyperkalaemia
• Eg severe burns, rhabdomyolysis, tumour lysis as a result of chemotherapy

Question 5

Hyperkalaemia

Internal balance shift

Excercise

Answer 5

Question 6

Hyperkalaemia

External balance shift

Answer 6

External balance shifts normally caused by the kidneys

Does this via the nephron

Question 7

Hyperkalaemia

External balance shift

Nephron

Answer 7

Aldosterone regulates K⁺

Adrenal insufficiency wiil cauae less aldosterone to be secreated

More K⁺ is retained leading to Hyperkalaemia

Also a number of drugs that retain K⁺

Renin inhibitors, Ace inhibitors, Angiotensin II receptor antagonists

Selective Aldosterone inhibitors K⁺ sparing diuretics

Question 8

Hyperkalaemia

External balance shift

Acute Kidney Injury

Answer 8

Low GFR via AKI can lead to Oliguria and Hyperkalaemia

Too much K in the blood can raise the resting potential of cell causing muscle cramps

In skeletal muscle can cause weakness and flaccid paralysis

Question 9

Hyperkalaemia

Diagnosis

Answer 9

Peaked T waves on ECG seen on leads V1-V6

ST segment depression

Short QT interval

When severe can get a prolonged PR interval, absent P wave and a wide QRS complex

Question 10

Hyperkalaemia

Treatment

Answer 10