Disorders of Potassium metabolism

Dr. Hammed Al shakhatrehConsultant Nephrologist

• Total body K is about 3500 m moll 2 % extracellular 98% intracellular

• S.K 3.5- 5.3 m mol/ litter normally regulation of S.K is by kidney and GI firstly, secondly by shifting.

Renal regulation

• Aldosterone• High distal Na delivery • High urine flow rate• High K in tubular cells• Metabolic alkalosis

Others Route of excretion is GI system by diarrhea and vomiting. The last system to regulate of S.K is by shifting from cells outside by acidosis and into cells by alkalosis also by Insulin and epinephrine

Hypo kalmia S.K < 3.5 mmol/L

1- Low intake 2- Losses 3- Shifting

To differentiate between renal and extrarenal causes in Hypokalemic patients urine K > 20 mmol/L suggests a renal etiology where's urine K < 20 mmol/L suggests an extrarenal etiology.

Causes of Hypokalemia

• Inadequate potassium intake (severe malnutrition)• Extrarenal potassium losses Vomiting Diarrhea

• Hypokalemia due to urinary potassium losses Diuretics (loop, thiazides, acetazolamide) Osmotic dieresis (hyperglycemia)

Hypokalemia with hypertension

• Primary aldosteronism• Glucocorticoid remediable hypertension • Malignant hypertension• Renovascular hypertension• Rennin-secreting tumor• Essential hypertension with excessive diuretics

• Liddle's syndrome• 11 β -hydroxysteroid dehydrogenase deficiency Genetic• Drug-induced (chewing tobacco, licorice, some

French wines)• Congenital adrenal hyperplasia

Hypokalemia with a normal blood pressure

• Distal RTA (type 1)• Proximal RTA (type 2)• Bartter's syndrome• Gitelman's syndrome• Hypomagnesaemia (cisplatinum, alcoholism,

diuretics)

Hypokalemia due to potassium shifts

• Insulin administration• Catecholamine excess (acute stress)• Familial periodic hypokalemic paralysis• Thyrotoxic hypokalemic paralysis

clinical manifestation of Hypokalmia

1. Muscle weakness 2. Constipation, distended abdomen 3. Polyuria 4. Arrhythmia specially in patient taking dioxin. 5. ECG- U wave, ST depression

Treatment of Hypokalmia

Potassium Chloride I.V allowed 200mmol/day and urgently 60 m mol/hour in central line under monitoring

Hyperkalemia

• Serum potassium > 5.3 m mol/L• Pseudohyerkalemia seen in blood haemolysis after

drawing from the patient Pseudohyperkalemia

• Hemolysis • Thrombocytosis• Severe leukocytosis• Fist clenching

True Hyperkalemia• Acute or chronic renal failure• Aldosterone deficiency (type 4 renal tubular

acidosis) Frequently associated with diabetic nephropathy,

chronic interstitial nephritis, or obstructive nephropathy.

• Adrenal insufficiency (Addison's disease)• Drugs that inhibit potassium excretion• Kidney diseases that impair distal tubule function

• Sickle cell anemia• Systemic lupus erythematosus• Abnormal potassium distribution • Insulin deficiency • β -blockers • Metabolic or respiratory acidosis• Familial hyperkalemic periodic paralysis• Abnormal potassium release from cells• Rhabdomyolysis• Tumor lysis syndrome

Clinical manifestation • muscle weakness• Paralysis

ECG manifestation • Peak T wave • Wide QRS• Prolonged PR up to absent P wave• Sine wave • Ventricular Fibrillation

Treatment of Hyperkalmia

- S.K 5.5-6.5 without ECG manifestations don’t treat. - S.K 5.5-6.5 with ECG manifestations treat . - S.K > 6.5 treat 1. I.V calcium2. Give insulin with GW3. Beta agonist4. Kayexalate GIVE 50 g in 30 ml Orbital by mouth or 50 g in a

retention enema. 5.Haemodialysis.

What is the diagnosis?

1. Digoxin poisoning2. Hyperkalemia3. Intra-aortic balloon pump4. Pericardial effusion5. Right fascicular block

Image Challenge

Q. What is the diagnosis? Answer:

2. Hyperkalemia

The electrocardiogram shows a regular rhythm, with a widened QRS complex in a sine-wave configuration, and there no discernible P waves. The T waves were fused with the widened QRS complexes to form the sine-wave pattern (sinoventricular rhythm). The patients serum �potassium level was 9.1 mmol per liter. His condition stabilized after the administration of calcium chloride, bicarbonate, glucose, and insulin therapy, which was followed by hemodialysis

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