1. This lecture was conducted during the Nephrology Unit Grand Ground by Nephrology Registrar under Nephrology Division, Department of Medicine in King Saud University. Nephrology Division is not responsible for the content of the presentation for it is intended for learning and /or education purpose only.

2. 2

3. Definition of hyperkalemia. Factors regulating the distribution of potassium between the intra/extracellular space. Causes of hyperkalemia. Sign and symptoms. Diagnosis. Treatment. 3

4.  hyperkalemia means an abnormally elevated level of potassium in the blood. The normal potassium level in the blood is 3.5-5.0 milliequivalents per liter (mEq/L). 5.5-6.0 mEq/L - Mild 6.1-7.0 mEq/L - Moderate 7.0 mEq/L and greater – Severe 4

5.  Potassium is the most abundant intracellular cation. Potassium is crucial to heart function and plays a key role in skeletal and smooth muscle contraction, making it important for normal digestive and muscular function.  Nearly 98% of potassium is intracellular and the remaining 2% is extracellular. The concentration gradient maintained by the sodium- and potassium- activated adenosine triphosphatase (Na+/K+ –ATPase) pump. 5

6.  Glucoregulatory hormones Insulin Glucagon  Adrenergic stimuli Beta-adrenergic stimuli Alpha-adrenergic stimuli  pH Alkalosis Acidosis  Shift from intracellular pool Acute increase in osmolality, such as hyperglycemia, causes potassium to exit from cells Acute cell-tissue breakdown releases potassium into extracellular space 6

7. Medication Ineffective elimination Excessive release from cell Excessive intake Pseudo hyperkalemia 7

8.  Potassium is normally excreted by the kidneys, so disorders that decrease the function of the kidneys can result in hyperkalemia. These include: acute and chronic renal failure (the most common) glomerulonephritis, lupus nephritis, transplant rejection, and obstructive diseases of the urinary tract, such as urolithiasis 8

9.  Diseases of the adrenal gland: Aldosterone causes the kidneys to retain sodium and fluid while excreting potassium in the urine. Therefore diseases of the adrenal gland, such as Addison's disease, that lead to decreased aldosterone secretion can decrease kidney excretion of potassium, resulting in body retention of potassium, and hence hyperkalemia. 9

10.  It was found that patients at their extreme age, premature infants and elderly people have a higher risk of developing hyperkalemia with renal insufficiency playing a significant role.  Premature infants : renal immaturity is likely to be a contributory factor. often occurs within the first 48 hours of life.  Elderly patients : Several factors contributing to hyperkalemia.  Renal function tends to deteriorate with age, even in relatively healthy individuals. The glomerular filtration rate decreases by 1 mL/min/y in people older than 30 years. Renal blood flow also decreases. Plasma renin activity and aldosterone levels also tend to decrease with age, reducing the ability of the distal nephron to secrete potassium.  Elderly patients are more likely to be taking medications that could interfere with potassium secretion, such as nonsteroidal anti-inflammatory drugs, angiotensin-converting enzyme inhibitors, and potassium-sparing diuretics. heparin, which can decrease aldosterone production. 10

11.  diabetic ketoacidosis.  tissue destruction causing hyperkalemia include: trauma, burns, surgery, hemolysis (disintegration of red blood cells), massive lysis of tumor cells, and rhabdomyolysis 11

12. High-potassium, low-sodium diets. Potassium supplements. or potassium chloride (KCl) infusion. ACE inhibitors, ARBs, NSAIDs, potassium-sparing diuretics. 12

13. It is a laboratory artifact rather than a biological abnormality and can be misleading to caregivers. Pseudo hyperkalemia is typically caused by hemolysis during venipuncture or by a delay in the processing of the blood specimen. It can also occur in specimens from patients with abnormally high numbers of platelets (>500,000/mm³), leukocytes (> 70 000/mm³), or erythrocytes (hematocrit > 55%). 13

14.  Symptoms are nonspecific and predominantly related to muscular or cardiac function.  Hyperkalemia frequently is discovered as an incidental laboratory finding. nausea, fatigue, muscle weakness, or paralysis tingling sensations. Palpitation Cardiac arrhythmia and sudden death 14

15.  Measurement of potassium level needs to be repeated, as the elevation can be due to hemolysis in the first sample.  Assess renal function: BUN and creatinine level  CBC : Low hemoglobin level or abnormal red cell morphology may suggest hemolysis. Leukocytosis or thrombocytosis  metabolic profile: Low bicarbonate may suggest hyperkalemia due to metabolic acidosis. Hyperglycemia suggests diabetes mellitus.  ECG: may show changes typical for hyperkalemia in moderate to severe cases. 15

16. 16

17. 17

18. 18

19. 19

20.  Treatment of hyperkalemia must be individualized based upon: 1. the underlying cause. 2.the severity of symptoms or appearance of ECG changes. 3.the overall health status of the patient. 20

21.  Treatment of hyperkalemia may include any of the following measures, either singly or in combination: A diet low in potassium (for mild cases). Discontinue medications that increase blood potassium levels. Intravenous administration of glucose and insulin. Intravenous calcium to temporarily protect the heart and muscles from the effects of hyperkalemia. Sodium bicarbonate to counteract acidosis. Diuretic administration to decrease the total potassium stores through increasing potassium excretion in the urine except potassium-sparing diuretics. Medications that stimulate beta-2 adrenergic receptors. Medications known as cation-exchange resins, which bind potassium and lead to its excretion via the gastrointestinal tract. Dialysis, particularly if other measures have failed or if renal failure is present. 21

22. 1.Chew HC, Lim SH. Electrocardiographical case. A tale of tall T's. Hyperkalaemia. Singapore Med J. Aug 2005;46(8):429-32; quiz 433. [Medline]. 2.Don, BR; Sebastian, A; Cheitlin, M; Christiansen, M; Schambelan, M (May 1990). "Pseudohyperkalemia caused by fist clenching during phlebotomy". N. Engl. J. Med. 322 (18): 1290–1292. doi:10.1056/NEJM199005033221806. PMID 2325722. 3.emedicine.medscape.com/article/240903. 4.Kratz, A; Ferraro, M; Sluss, PM; Lewandrowski, KB; Ellender, Stacey M.; Peters, Christine C.; Kratz, Alexander; Ferraro, Maryjane et al. (2004). "Case records of the Massachusetts General Hospital. Weekly clinicopathological exercises. Laboratory reference values". The New England journal of medicine 351 (15): 1548–63. doi:10.1056/NEJMcpc049016. PMID 15470219. 5.medicinenet.com/hyperkalemia/article.htm. 6.Seifter JL. Potassium disorders. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 118. 7.Tran HA. Extreme hyperkalemia. South Med J. Jul 2005;98(7):729-32. [Medline]. 22

23. 23