Electrolyte Abnormalities in the Transplant Recipient

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1 Electrolyte Abnormalities in the Transplant Recipient Michael J. Goldstein, MD Assistant Professor of Surgery Overview Sodium Potassium Calcium Magnesium Phosphorus Sodium Balance Na + determines extracellular fluid osmolarity 2 x plasma [Na + ] = 290 mosm or 2 x plasma [Na + ] + [glucose]/18 + [BUN]/2.8 Maintaining ECF volume is critical to maintaining SBP and therefore, organ perfusion 1

2 HYPERNATREMIA Great Salt Lake of Utah Hypernatremic Effects Cells become dehydrated Alteration of MS and consciousness Stretching and rupture of veins causing intracranial hemorrhage Cerebral edema may ensue from rapid resuscitation Hypernatremia Decreased free water supply Water loss Diarrhea Insensible losses Osmotic diuresis Solute load 2

3 Transplant Hypernatremia [Na + ] balance in the post-transplant transplant setting is almost all related to volume resuscitation and/or diuretics Living-donor renal transplant recipients that are under fluid resuscitated Over-resuscitation resuscitation with NS Post-transplant transplant DM with osmotic diuresis Lactulose in encephalopathic liver recips Transplant Hypernatremia Treatment Free water replacement 0.6 X body weight X [(PNa/140)-1] 1] Rate of correction < 0.5 meq/hour Treat hyperglycemia for management of osmotic diuresis HYPONATREMIA Hoover Dam. Nevada/Arizona border 3

4 Hyponatremic Effects Cerebral edema Seizures Memory impairment Coma Brainstem herniation,, brain death Hyponatremia MOST COMMONLY REFLECTS INCREASE IN FREE WATER RELATIVE TO EXCRETION Increased supply vs. decreased excretion Hyperosmolar Isoosmolar Hypoosmolar Hyperosmolar Hyponatremia Osmolar gap 2Na + glucose/18 + BUN/2.8 GAP > 10 presence of osmotic substance Endogenous Acetone ARF Lactate Exogenous Methanol, Ethlene Glycol, Ethanol, Glycine, Mannitol 4

5 Isoosmolar Hyponatremia Lipids/proteins Calculate osmolar gap Hypoosmolar Hyponatremia Impaired renal free water excretion Too few nephrons Too much ADH (volume depletion, thyroid) SIADH Increased free water supply Psychogenic polydipsia Uosm low; <100mosm/L Transplant Hyponatremia Hepatorenal syndrome in pretransplant cirrhotic patients Portal HTN and ascites in cirrhotic patients Renal transplant recipients with ATN or DGF Renal recipients with acute rejection All transplant patients with CNI related renal impairment Dehydration from hyperglycemia, infection, diarrhea 5

6 Transplant Hyponatremia ALL FORMS RESPOND TO WATER RESTRICTION Cirrhotic patients with HRS or Portal HTN Salt restriction, K sparing diuretics, alpha agonists (Mitodrine( Mitodrine), ADH antagonists, TIPS, transplantation DGF or ATN in renal recipients Fluid restriction, dialysis Renal impairment from rejection or CNI toxicity Fluid restriction, treatment for rejection, reduce CNI Hyperosmolar crisis from hyperglycemia NS resuscitation, insulin infusion Severe dehydration from infectious diarrhea, or MMF NS resuscitation, treatment of diarrhea Potassium Balance Intake Cellular Shift Excretion HYPERKALEMIA 6

7 Hyperkalemic Effects Fatigue Weakness Cardiac depression Palpitations Life-threatening arrhythmia Hyperkalemia Intake (rarely sole cause) Cellular Shift Acidosis Muscle damage (surgery) Lack of insulin Drugs, Digoxin, Succinylcholine Excretion CKD Hypoaldosteronism Drugs, CNI, K sparing diuretics Transplant Hyperkalemia Cellular shift Hyperchloremic metabolic acidosis from NS infusion during renal transplant Post-operative operative renal or hepatic transplant recipient from tissue lysis or reperfusion Insulin dependent diabetic recipients without post- operative insulin replacement 7

8 Transplant Hyperkalemia Excretion CKD patients for renal transplant Renal recipients with DGF or rejection Liver recipients with CKD or HRS Severe dehydration from infection Drugs Drugs CNI cause distal tubule impairment Aldactone Transplant Hyperkalemia TREATMENT Shift Insulin/glucose (temporary) Bicarbonate infusion (temporary) Stabilization of membrane action Calcium infusion Removal Diuretics Binding with kayexelate (NOT POST-OP) OP) Dialysis HYPOKALEMIA 8

9 Hypokalemic Effects Cardiac hyperexcitability Palpitations, arrhythmias Paralysis, paresthesias Constipation, cramping Delirium Hypokalemia Cellular Shift Alkalosis Insulin therapy Excretion GI Hyperaldosteronism Diuresis Hypomagnesemia Amphotericin-B Transplant Hypokalemia Cellular Shift IDDM patients receiving insulin infusions Hyperglycemia, nausea and vomiting Excretion Diarrhea from lactulose or MMF Diuretics used for post-op op fluid removal after renal or hepatic transplant LRT failure to concentrate urine Ampho-B B treatment for resistant fungal infection 9

10 Transplant Hypokalemia TREATMENT Estimation of deficit is difficult ~100 meq for 1meq/L deficit PO therapy usually best route 10meq/hour IV peripherally, 20meq/hour IV centrally Check magnesium and replete aggressively in addition to potassium Calcium Balance Intake Diet Absorption/GI Cellular/Bone shift 99% bone, 1% ECF (40% bound) Excretion Renal HYPOCALCEMIA 10

11 Hypocalcemic Effects Cramping Numbness Tingling sensation CHF Syncope Dry skin Brittle nails Hypocalcemia Hypoalbuminemia Corrected=Measured [Ca] +0.8 X (4.4-serum albumin) Hypomagnesemia End-organ resistance to PTH Hyperphosphatemia Phosphate binds calcium avidly Sepsis Hepatic or renal insufficiency Transplant Hypocalcemia Hypoalbuminemia in patients with liver disease, check ionized or correct for low albumin Living-donor renal recipients with inability to concentrate urine, do not correct for low calcium until phosphorus is cleared 11

12 HYPERCALCEMIA Hypercalcemic Effects Nausea Vomiting Change in mental status Constipation Lethargy Weakness Hypercalcemia PTH mediated increased absorption in the gut Primary hyperparathyroidism Secondary hyperparathyroidism Tertiary hyperparathyroidism Non PTH mediated bone resorption from increased osteoclast activity from malignancy 12

13 Transplant Hypercalcemia Renal failure induced hyperphosphatemia causing secondary and tertiary hyperparathyroidism Transplant Hypercalcemia TREATMENT Acute Hydration with saline Diuretics - Lasix Bisphophonates Pamidronate, Etidronate hemodialysis Chronic Parathyroidectomy Effective hemodialysis Sensipar lowers PTH levels Magnesium Balance Intake Cellular Shift Excretion 13

14 HYPOMAGNESEMIA Magnesium from the Sea Hypomagnesemic Effects Neuromuscular irritability Muscle cramps Dysarthria and dysphagia CNS hyperexcitability Seizures (CNI lower threshold) Ataxia Irritability Hypomagnesemia Intake malabsorption Shift Insulin administration Post-parathyroidism (hungry bone syndrome) Excretion (renal) Post-ATN Post-renal transplant Diuretics 14

15 Transplant Hypomagnesemia Post-obstructive obstructive diuresis Living-donor renal recipients with inability to concentrate urine Low magnesium in setting of CNI-based immunosuppression predisposes to CNS toxicity and seizures Transplant Hypomagnesemia TREATMENT Oral Oral Magnesium Oxide Mg antacids (TUMS) MOM Magnesium sulfate or citrate IV Bolus/infusion Goal for serum value 2.0 mg/dl HYPERMAGNESEMIA Intake Mg containing laxatives/antacids IV replacement Shift DKA Tissue Injury Excretion 15

16 Hypermagnesemic Effects Inhibition of neuromuscular transmission Inhibition of cardiac conduction Lethargy EKG changes Respiratory failure Muscle Paralysis Asystole Transplant Hypermagnesemia Rare Antacid use or laxative use with renal insufficiency Transplant Hypermagnesemia TREATMENT IV Calcium for membrane stabilization Hemodialysis 16

17 Phosphorus Balance Intake Malabsorption Diarrhea Alcoholism Cellular shift Respiratory alkalosis Insulin Refeeding syndrome, carbohydrates Excretion Renal PTH HYPOPHOSPHATEMIA "The Discovery of Phosphorus" by the English painter, Joseph Wright ( ), 1797), of Derby, England. Hypophosphatemic Effects Weakness Diplopia Dysarthria Dysphagia Respiratory depression Myocardial depression Neurologic changes 17

18 Transplant Hypophosphatemia Post-renal transplant inability to reabsorb in the proximal tubule Loop and thiazide diuretics Hepatic encephalopathy causing respiratory alkalosis Post-transplant transplant DKA Tertiary hyperparathyroidism Hepatic regeneration after donor hepatectomy Transplant Hypophosphatemia TREATMENT Moderate 1-22 mg/dl Oral preparations 2-33 grams of elemental phos in divided doses (neutraphos( or Kphos) Severe - <1 mg/dl IV repletion (Sodium or potassium phosphate) 8 mmol of KPhos IV q6 hours HYPERPHOSPHATEMIA Phosphorus and Hesperus Evelyn De Morgan 18

19 Hyperphosphatemic Effects Hypocalcemia Calcium phospate deposition, calciphylaxis Atherosclerosis, Vascular calcium deposition Transplant Hyperphosphatemia Acute or chronic renal failure Transplant Hyperphosphatemia TREATMENT Binding resins such as Renagel Hemodialysis or peritoneal dialysis Replace hypocalcemia only if symptomatic, may precipitate metastatic calcification 19

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