نفرولوژیست استادیار دانشکده پزشکی دکتر عبدالامیر عطاپور نفرولوژیست استادیار دانشکده پزشکی

CASE STUDY 1 32 years of age a female patient Medications Hypertension Asthma Medications Albuterol Atenolol Hydrochlorothiazide

Admitted for exacerbation of asthma secondary to bronchitis Treated Albuterol treatments every 3 hours Cephalosporin antibiotic Prednisone taper Her Atenolol is stopped

After 24 hours severe muscle cramps Her admission potassium level was 3.9 mEq/L A basic metabolic profile reveals normal renal function and a potassium level of 2.9 mEq/L

What do will do ? Kcl orally? 20 mEq/L K in NS ? 20 mEq/L k in DW ? 20 mEq/L in manitol ? 6 mEq/L direct IV ?

40 mEq of potassium immediately prescribed 40 mEq twice daily with close monitoring of her level.

Causes of hypokalemia DECREASED POTASSIUM INTAKE INCREASED ENTRY INTO CELLS INCREASED GASTROINTESTINAL LOSSES INCREASED URINARY LOSSES  

DECREASED POTASSIUM INTAKE  Potassium intake is normally 40 to 120 meq per day In the presence of potassium depletion The kidney is able to lower potassium excretion to a minimum of 5 to 25 meq per day

INCREASED ENTRY INTO CELLS More than 98 percent of total body potassium is intracellular Increased availability of insulin  Elevated beta-adrenergic activity Endogenous catecholamines Acting via beta-2 adrenergic receptors Na-K-ATPase pump and the Na-K-2Cl (NKCC1) cotransporter possibly Increasing the release of insulin

Elevation in extracellular pH The serum potassium concentration falls by less than 0.4 meq/L for every 0.1 unit rise in pH Organic acid Inorganic acid

Hypokalemic periodic paralysis Reduce the serum potassium to as low as 1.5 to 2.5 meq/L, are often precipitated by rest after exercise, stress, or a carbohydrate meal.

Increased blood cell production Hypothermia Vit B12 & Folate Hypothermia  Drive potassium into the Barium intoxication —  Ingestion of contaminated food or from a suicide attempt Cesium intoxication For cancer, can be associated with hypokalemia

Chloroquine intoxication Antipsychotic drugs  Hypokalemia is a rare complication of therapy with selected antipsychotic drugs Risperidone  Quetiapine

INCREASED GASTROINTESTINAL LOSSES Upper gastrointestinal losses  The concentration of potassium in gastric secretions is only 5 to 10 meq/L Lower gastrointestinal losses  the potassium concentration in lower intestinal losses is relatively high (20 to 50 meq/L)

INCREASED URINARY LOSSES Increased mineralocorticoid activity Increased distal delivery of sodium and

Major causes of urinary potassium wasting The most common causes of hypokalemia due to urinary potassium losses include Diuretic Primary increase in mineralocorticoid activity Increased distal delivery of nonreabsorbable anions Loss of gastric secretions

Non reabsorbable anions Bicarbonate Beta-hydroxybutyrate in diabetic ketoacidosis Hippurate following toluene use (glue-sniffing) Penicillin derivative in patients receiving high-dose penicillin therapy

Less common causes of urinary potassium wasting Polyuria  Potassium depleted subjects can normally reduce the urine potassium concentration to a minimum of 5 to 10 meq/L Renal tubular acidosis  Hypomagnesemia  via an uncertain mechanism Amphotericin B  Salt-wasting nephropathies  Liddle's syndrome  Gittleman

Evaluation of the patient with hypokalemia REGULATION OF POTASSIUM EXCRETION  The urinary response to potassium depletion is twofold

ASSESSMENT OF URINARY POTASSIUM EXCRETION A 24-hour urine collection is the most accurate method Potassium excretion Higher 25 to 30 meq per day suggest at least a contribution from urinary potassium wasting. Random measurement Urine potassium concentration is higher than 15 meq/L suggest at least a component of potassium wasting.

Pitfall The effect of the diuretic has worn off Polyuria Urine volume is only 500 mL due to a low rate of water intake Urinary sodium excretion should be above 30 to 40 meq per day to avoid this problem.

Severe hypokalemia 24-hour potassium excretion is impractical on a single urine specimen Potassium-to-creatinine ratio Less than 13 meq/g creatinine Transtubular potassium concentration gradient. Do not recommend using the TTKG

ASSESSMENT OF ACID-BASE STATUS Metabolic acidosis with a low rate of urinary potassium excretion is suggestive of lower gastrointestinal losses Metabolic acidosis with urinary potassium wasting is most often due to diabetic ketoacidosis or to type 1 (distal) or type 2 (proximal) renal tubular acidosis.

Metabolic alkalosis + low rate of urinary potassium excretion =surreptitious vomiting Metabolic alkalosis + urinary potassium wasting and a normal blood pressure : Diuretic use Vomiting Gitelman Bartter syndrome

Metabolic alkalosis + urinary potassium wasting + hypertension: Surreptitious diuretic therapy in a patient with underlying hypertension, Renovascular disease, or primary mineralocorticoid excess

بیمار خانم 51 ساله که به دلیل دلدرد اتساع شکم و کاهش وزن مراجعه نموده بیمار سابقه استفراغ مکرر را داشته و از دو هفته قبل عدم دفع گاز و مدفوع داشته و در معاینه 5-6 کیلوگرم کاهش وزن داشته دستورات اولیه شامل سرم قندی نمکی + 10 سی سی کلرید پتاسیم هر 8 ساعت

نقایص شرح حال ؟

وازمایشات درخواستی CBC /Na/K/BS/LFT /PT/PTT 6واحد خون رزرو سفازولین رانیتیدین شیاف دیکلوفناک جواب آزمایشات روز اول Na=140 /K=2.9 / Cr = 0.6 / BUN =13 / WBC = 6400 / Hb= 9.1 // PLT = 245

کدام درمان را بهتر میدانید؟ انجام لاپاراتومی و اصلاح انسداد اصلاح هیپوکالمی

انجام لاپاراتومی و اصلاح انسداد بیمار لاپاراتومی شده ولی بهبودی نداشته شکم متسع بوده دستورات شامل انتی بیوتیک و سرم رینگر و رانیتیدین وریدی بوده

اصلاح هیپوکالمی Kcl orally? 20 mEq/L K in NS ? 20 mEq/L k in DW ? 20 mEq/L in manitol ? 6 mEq/L direct IV ?

Kcl orally? 20 -30 meq 3-4 timse per day

چه مواقعی 20 mEq/L K in NS ? 20 mEq/L k in DW ? 20 mEq/L in manitol ? 6 mEq/L direct IV ?

جواب آزمایشات بعد از عمل WBC=1800 / Hb = 9 جواب آزمایشات بعد از عمل WBC=1800 / Hb = 9.7 / PLT = 97000 / Na = 157 / K = 2.9 بعد از عمل حال عمومی بیمار خوب بود ه اختلال همودینامیک نداشته شکم هنوز متسع بوده و تهوع و استفراغ ندارد بیمار ترخیص شده و چند ساعت بعد فوت شده

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