K disorders

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K disorders:

K disorders Dr Mohammed Abdelsattar

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M ajor intraellular cation N ormal range 3.5-5 mmol /l

Top foods containing potassium:

T op foods containing potassium Potato (1,081 mg) Spinach (839 mg) Baked beans (752 mg)  Raisins (544 mg)  Avocados (540 mg) Yogurt, low-fat (531 mg)  Orange juice (496 mg)  Cantaloupe (494 mg)  Tuna (484 mg)

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Small increases in serum potassium induce insulin release . Also, when a dietary potassium load is ingested, we also ingest a dietary glucose load, which promotes the release of insulin. Insulin enhances the entry of potassium into skeletal muscle and the liver by increasing the activity of the Na-K- ATPase pump . This results in minimizing the rise in plasma potassium

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Hyperkalemia

exclude pseudohyperkalaemia:

exclude pseudohyperkalaemia Obtaining a plasma potassium , rather than a serum potassium, will differentiate pseudohyperkalemia from true hyperkalemia . repeat serum potassium should be ordered urgently, especially if hyperkalaemia is an unexpected or isolated finding and there are no ECG signs of hyperkalaemia

Symptoms and signs:

S ymptoms and signs muscle weakness or flaccid paralysis palpitations, paresthesias

ECG changes:

ECG changes T all peaked t wave A bsent p wave W ide qrs P prolonged pr S ine wave

Normal ECG doesnt exclude risk of cardiac arrest:

N ormal ECG doesnt exclude risk of cardiac arrest so ECG is insensitive

When we start ttt:

W hen we start ttt I f hyperkalemia associated with ECG changes I f K more than 6.5mmol/l ECG changes or above symptoms even in the presence of mild hyperkalaemia K 5.5 - 6.0

ttt:

ttt Stop further potassium accumulation Stop all potentially offending drugs immediately

three approaches :

three approaches • antagonizing the membrane effects of potassium – Using calcium • driving extracellular potassium into the cells – Insulin with glucose, beta-2-adrenergic agonists and sodium bicarbonate • Removing excess potassium from the body – Diuretics, Resins or Dialysis

calcium:

calcium Protect the cardiac membrane High levels of potassium induce depolarization of the resting membrane potential which leads to inactivation of sodium channels and decreased membrane excitability. This leads to the cardiotoxicity of hyperkalemia Give 10ml of calcium gluconate 10% intravenously over 2 minutes This intervention will not lower the potassium, but if ECG changes are present, there should be improvement seen within 1 to 3 minutes

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If improvement does not occur a Further 10ml of calcium gluconate 10% can be given intravenously every 10 minutes until the ECG normalises patients may require up to 50ml The effect of this intervention is transient approximately 30 minutes

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It is important to note that if the patient is taking digoxin and the decision is made that calcium gluconate is required, it should be given slowly over 20 minutes mixed in 100ml of glucose 5% As rapid calcium administration may precipitate myocardial digoxin toxicity

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O nce we stabilize the cell we shift potassium into the cell

Glaucose insulin:

G laucose insulin I nsulin shift potassium into the cell I deal we give one unit of insulin to every 2.5 G m glauose Withdraw 10 units of Actrapid insulin using an INSULIN syringe. . Add to 50ml glucose 50% and administer by slow IV injection over 5 minutes

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The effects of administering insulin/glucose are observed in 15 minutes and last 4-6 hours The reduction in potassium observed ranges 1 mmol /l in 1 hour Monitoring – blood glucose should be measured 30 minutes after starting the infusion and then hourly up to six hours after completion of the infusion as delayed hypoglycaemia is commonly reported when less than 30g of glucose is administered with insulin 250 O nly give glauose if its level less than

sodium bicarbonate:

sodium bicarbonate not recommended many studies show that sodium bicarbonate fails to lower the serum potassium. There are also potential risks in giving sodium bicarbonate in terms of volume and sodium overload and tetany in patients with chronic renal failure and co-existent hypocalcaemia. The risks outweigh any potential benefit.

Albuterol:

Albuterol nebulized or IV. Nebulized form is 10-20 mg in 4ml of saline by nebulization over 10 Minutes So give 2 cm farcoline in 4 cm saline IV form is 0.5 mg by intravenous infusion C an lower potassium by one mmol/l in half or one hour T here effect last two hour V ery effetive in renal patient that are fluid overloaded Due to potential tachycardia and possible Angina albuterol should be avoided in patients with coronary disease

Normal saline and diuretics:

N ormal saline and diuretics U sing saline and k loosing diureics help to decrease potassium and inrease urine output

cation-exchange resins:

cation -exchange resins Calcium polystyrene sulphonate resin ( Calcium Resonium ) enema 30g followed with 15g orally 4 times daily with regular lactulose will increase gut losses of potassium

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When given rectally the calcium resonium must be retained for 9 hours followed by irrigation to remove resin from the colon to prevent faecal impaction. Bowel perforation can be a c omplication

Haemodialysis:

Haemodialysis If despite the above measures the potassium remains greater than 7mmol/l or if pathological ECG changes/symptoms persist arrange urgent dialysis if appropriate

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This is the most effective and definitive but invasive method in treating hyperkalaemia . It is strongly considered if hyperkalaemia is severe (level debated but ³7.0mmol/l) and other first-line agents have been unsuccessful, or if there is ongoing tissue damage and continued release of intracellular potassium is expected

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Hypokalemia

aetiology:

aetiology shift of potassium intracellularly will occur in the following settings: metabolic alkalosis , insulin loading , and beta-2-adrenergic stimulation loop or thiazide diuretics cause renal potassium loss

ECG changes occur in patients with hypokalemia:

ECG changes occur in patients with hypokalemia ST segment depression, T-wave flattening increased U-wave amplitude (waves that occur at the end of the T wave), and ventricular fibrillation

signs and symptoms:

signs and symptoms As hypokalemia progresses nonspecific symptoms develop, such as weakness and malaise. When serum potassium drops below 2.0 mEq /L , it can precipitate muscle necrosis and paralysis, causing respiratory failure

ttt:

ttt If hypokalemia is mild and asymptomatic and there are no ongoing losses, it is reasonable to use oral replacement with 10 to 20 mEq of potassium chloride two to three times per day until the potassium is 3.0 mEq /L

PowerPoint Presentation:

If the hypokalemia is moderate and asymptomatic (3.0 mEq /L) and there are no ongoing losses, it is reasonable to give oral potassium chloride 40 to 60 mEq two to three times per day until the potassium is 3.0 mEq /L If there are ongoing losses present (i.e., diuretics, vomiting, diarrhea), this can be scheduled i.V should be used

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Check serum Mg levels since it is difficult to restore K if the former is low

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Thanks

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