Electrolytes

1. Electrolytes Intern Boot Camp

2. Case (in reverse) You are pronouncing Professor Plum dead (in Lakeside Library, but how and by whom ????????).

3. 5 minutes ago�. The nurse calls to tell you that the good professor is having palpitations and is feeling lightheaded. You instruct him to check an ECG while you review the patient�s history.

4. 5 minutes ago� You find out that Professor Plum was admitted with acute renal failure and his morning labs demonstrated:

5. What Should You Do? Calcium Gluconate (10%) 10ml IV over 3 minutes, can be repeated in 5 minutes Calcium Gluconate stabilizes the cardiac membranes against the actions of hyperkalemia Does nothing to reduce circulating K+; effects only last 20-30minutesDoes nothing to reduce circulating K+; effects only last 20-30minutes

6. What Should You Do? Reduce the circulating K+�.

7. What Should You Do? Reduce the circulating K+�. 10 units regular insulin with 1-2 amps of dextrose. Kayexelate 30mg PO or 50mg rectally Furosemide 40mg IV Hemodialysis

8. 5 hours ago� Professor Plum is admitted to the floor to your sister team; his admission ECG demonstrates: Peaked T- waves typically seen when the K+ gets to 6. Also look for PR interval prolongation.Peaked T- waves typically seen when the K+ gets to 6. Also look for PR interval prolongation.

9. 5 days ago� Professor Plum presented to his PCP for an annual check up who added spironolactone to his HTN regimen and increased the dose of his lisinopril, HCTZ combo pill. The PCP also encouraged the use of NSAIDs for chronic back pain. Plum was given a script for a 10 day course of bactrim for suspected case of lower extremity cellulitis.

10. Causes of Hyperkalemia Renal Failure Drugs (ACEIs, ARBs, Beta-Blockers, K+ sparing diuretics, Digitalis, NSAIDs, TMP-SMX, Heparin) Adrenal Insuffiency Rhabdomyolysis Tumor Lysis Trans-Cellular Shifts (DKA)

11. Hypokalemia Symptoms: hypokalemia distorts the resting membrane potential? skeletal muscle, smooth muscle, and cardiac muscle effected Skeletal Muscle: weakness, cramps, possible rhabdo Smooth Muscle: paralytic ileus Cardiac Muscle: ECG changes, ventricular arrhythmias

12. Hypokalemia Early changes include flattening or inversion of the T wave, a prominent U wave

13. Hypokalemia � A. Nonrenal�� 1. Gastrointestinal loss (diarrhea) 2. Integumentary loss (sweat)��� B. Renal��� 1. diuretics, osmotic diuresis, salt-wasting nephropathies 2. Increased secretion of potassium: Mineralocorticoid excess/ hyperaldosteronism��/ Type 2 RTA

14. Hypokalemia Treatment: PO options: 20-40mEq; can recheck levels 4 hours after last dose Parenteral Options: 20-40mEq (in 500cc peripherally or 100cc via central access) Expect K+ to increase by 0.1 for every 10eEq given

15. Hypernatremia:Workup Symptoms: hypertonic state? fluid shift out of cells (including brain)? mental status changes? seizures, coma History: evidence of free water losses, lack of access to free water, list of medications

16. HypernatremiaWorkup Free Water Losses GI: vomiting, diarrhea, NG suctioning Renal: osmotic diuresis (hyperglycemia) Dermal: burns, sweat Impaired access to Free Water - elderly, intubated Medications - lactulose, loop diuretics, lithium

17. HypernatremiaWorkup Physical Exam: -volume status 1) orthostatics 2) resting HR 3) mucous membranes 4) skin turgor Labs: repeat renal panel, check UA (specific gravity), urine volume, urine osmolality

18. Hypernatremia Workup

19. HypernatremiaTreatment Free Water Deficit = Body Weight (kg) X Percentage of Total Body Water (TBW) X ([Serum Na / 140] - 1) Percentage of TBW should be as follows: Young men - 0.6% Young women and elderly men - 0.5% Elderly women - 0.45%

21. HypernatremiaTreatment Correct the serum sodium no more than 0.5 mmol/L/ hour, 12mmol/L/day Too fast?cerebral edema

22. HypernatremiaExample 72 y/o (100kg) NH patient with remote history of stroke and residual L sided paresis with 2 days of fever. Labs show of sodium of 160. Change in Sodium/L infused: = (Infusate Na-Serum Na)/(TBW+1) = (0 (D5W)- 160)/ (45+1) = -3.5/ L infused

23. HypernatremiaExample So we want to decrease her Na by 12 over 24 hours. If we can decrease her Na by 3.5 with each L of D5W, she�d have to get 3.4L of D5W in the first day. 3.4L/24hr = 140ml D5W/hr

25. Hyponatremia Hyponatremia usually reflects a hypotonic state, but could also be seen in isotonic or even hypertonic conditions. The common presenting signs are again primarily neurologic: fluid shifts into the cells? cerebral edema? headache/confusion? seizure/coma (Na<120)

26. Hyponatremia Step 1: Determine the Plasma Osmolality: Posm= 2xNa + glucose/18 + BUN/2.8 Posm= measurable lab value Normal Osmolality = 290

27. Hyponatremia

28. Hypertonic Hyponatremia In hypertonic hyponatremia, some other osmotic agent is pulling water from the intracellular volume Most common = glucose - use corrected Na: for every increase of glucose above 100 by 100, Na drops by 1.4 Distant second = mannitol (used by neurosurgeons for increased intracranial pressure)

29. Hypertonic Hyponatremia So if your patient has the following labs, what is their corrected Na? Na: 129 K: 5.7 Cl: 102 HCO3: 12 Glu: 600

30. Hypertonic Hyponatremia So if your patient has the following labs, what is their corrected Na? Na: 129 K: 5.7 Cl: 102 HCO3: 12 Glu: 600

31. Isotonic Hyponatremia ? Pseudohyponatremia Historically, this has been seen in patients with hypertriglyceridemia or hyperproteinemia and was due to artificial errors by the lab. More sensitive machinery is common now, and these errors are a problem of the past.

32. Isotonic Hyponatremia May be seen in some urology patients (TURP, bladder tumor resections). The bladder is irrigated with high volume of hypoosmotic fluid, which can be temporarily absorbed causing a dilutional hyponatremia.

33. Hypotonic Hyponatremia Step 2: Check urine osmolality/specific gravity The normal renal response to a hypo-osmolar state is to secrete a maximal volume of maximally dilute urine (urine osmolality <100, specific gravity < 1.003)? as much as 12 liters a day�

34. Hypotonic Hyponatremia If the patient remains hyponatremic, despite making maximally dilute urine, they are taking in a sufficient amount of free water to overwhelm the kidney�s natural response. (1) Pyschogenic Polydipsia (ie crazy) (2) Beer Potomania (ie crazy awesome)

35. Beer Potomania... Not just for vets any more

36. Hypotonic Hyponatremia Step 3: Determine the fluid status

37. Hypervolemic Hyponatremia Examples: CHF, cirrhosis, nephrotic syndrome, renal failure Grossly fluid overloaded (lower extremity edema, ascites, pulmonary edema) BUT often intravascularly depleted. Antidiuretic Hormone (ADH, vasopressin) increases? free water retention

38. Euvolemic Hyponatremia SIADH (most common) Adrenal insufficiency Hypothyroidism

39. Hypovolemic Hyponatremia Renal losses (diuretics, adrenal insufficiency) Extra-renal (diarrhea, inadequate po, insensible loss)

40. Hyponatremia Treatment Treatment Hypervolemic- fluid restriction, +/- diuresis Euvolemic- free water restriction if due to SIADH, and patient is euvolemic, will worsen with normal saline, if due to SIADH use ADH antagonists, free water restriction, and treat underlying cause Hypovolemic- treat with normal saline

41. Hyponatremia Treatment Hypertonic should only be administered in the ICU setting with the aid of a fellow, and for CNS symptomatology In CNS affected patients you may correct the sodium at a more rapid rate of 1.5 � 2.0 meq/L/hr until symptoms resolve In non-CNS affected patients, correct at no more than 0.5 meq/L/hr with frequent metabolic panels